Vazaprostan

Overdose

Limited data are available in regard to Vazaprostan® (alprostadil for injection) overdose in humans. Systemic reactions are uncommon with intracavernous injection of Vazaprostan® (alprostadil for injection). Hypotension occurred in less than 1% of patients treated with Vazaprostan® (alprostadil for injection). A single dose rising tolerance study in healthy volunteers indicated that single intravenous doses of alprostadil from 1 to 120 mcg were well tolerated. Beginning with a 40 mcg bolus intravenous dose, the frequency of drug-related systemic adverse events increased in a dose-dependent manner, characterized mainly by facial flushing.

The primary symptom of an Vazaprostan® (alprostadil for injection) overdose is a prolonged erection or priapism. Because of the potential for tissue hypoxia and possible necrosis, it is strongly recommended to treat an erection lasting more than 6 hours. The patient is strongly encouraged to go to the nearest emergency room if his personal physician is not available.

In the event of an overdose, supportive therapy according to the presence of other symptoms is recommended.

Contraindications

Vazaprostan® (alprostadil for injection) should not be used in patients who have a known hypersensitivity to alprostadil or other prostaglandins, in patients who have conditions that might predispose them to priapism, such as sickle cell anemia or trait, multiple myeloma, or leukemia, or in patients with anatomical deformation of the penis, such as angulation, cavernosal fibrosis, or Peyronie's disease. Patients with penile implants should not be treated with Vazaprostan® (alprostadil for injection).

Vazaprostan® (alprostadil for injection) should not be used in men for whom sexual activity is inadvisable or contraindicated.

Vazaprostan® (alprostadil for injection) should not be used in women and children and is not for use in newborns.

Pharmaceutical form

Undesirable effects

Vazaprostan® (alprostadil for injection) , administered by intracavernous injection in doses ranging from 1 to 40 mcg per injection for periods up to 24 months, has been evaluated in clinical trials for safety in over 1,065 patients with erectile dysfunction. Discontinuation of therapy due to a side effect in clinical trials was required in approximately 9% of patients treated with Vazaprostan® (alprostadil for injection) and in < 1% of patients treated with placebo.

The following local adverse reactions were reported in studies including 1,065 patients treated with Vazaprostan® (alprostadil for injection) for up to two years.

Penile Pain: With use of up to 24 months, penile pain was reported at least once by 29% of patients during injection, 35% of patients during erection, and by 30% of patients after erection. On a per injection basis, 15% of injections were associated with penile pain. Penile pain was judged by patients to be mild in intensity for 80% of painful injections, moderate in intensity for 16% of painful injections, and severe in intensity for 4% of painful injections. The frequency of penile pain reports decreased over time; forty-one percent of the patients experienced pain during the first 2 months and 3% of the patients experienced pain during months 21-24. In placebo-controlled studies, penile pain was reported by 31% of patients after Vazaprostan® (alprostadil for injection) and by 9% of patients after placebo injection.

Prolonged Erection/Priapism: Prolonged erections greater than four hours in duration occurred in 4% of all patients treated up to 24 months. In placebo-controlled studies, 3% of patients treated with Vazaprostan® (alprostadil for injection) and < 1% of patients treated with placebo reported prolonged erections greater than four hours. The incidence of priapism (erections greater than 6 hours in duration) was < 1% with long-term use for up to 24 months. In the majority of cases, spontaneous detumescence occurred. A higher incidence of prolonged erections was found in younger patients ( < 40 years), non-diabetic patients, and patients with psychogenic etiology of erectile dysfunction. (See WARNINGS.)

Hematoma/Ecchymosis: In patients treated with Vazaprostan® (alprostadil for injection) for up to 24 months, local bleeding, hematoma and ecchymosis were observed in 15%, 5% and 4% of patients, respectively. In placebo-controlled studies, the frequency of local bleeding was 6% with injection of Vazaprostan® (alprostadil for injection) and 3% with injection of placebo. In most cases, these reactions were attributed to faulty injection technique.

Local Adverse Reactions Reported by ≥ 1% of Patients All Study Periods*

The following systemic adverse experiences were reported in controlled and uncontrolled studies in ≥ 1% of patients treated for up to 24 months with Vazaprostan® (alprostadil for injection).

Systemic Adverse Experiences Reported by ≥ 1% of Patients*

Hemodynamic changes, manifested as increases or decreases in blood pressure and pulse rate, were observed during clinical studies but did not appear to be dose-dependent. Four patients ( < 1%) reported clinical symptoms of hypotension such as dizziness or syncope.

Vazaprostan® (alprostadil for injection) had no clinically important effect on serum or urine laboratory tests.

Needle breakage.

Therapeutic indications

Vazaprostan® (alprostadil for injection) is indicated for the treatment of erectile dysfunction due to neurogenic, vasculogenic, psychogenic, or mixed etiology.

Pharmacokinetic properties

To ensure safe and effective use of Vazaprostan® (alprostadil for injection) , the patient should be thoroughly instructed and trained in the self-injection technique before he begins intracavernous treatment with Vazaprostan® (alprostadil for injection) at home. The desirable dose should be established in the physician's office. The instructions for preparation of the Vazaprostan® (alprostadil for injection) solution should be carefully followed. The reconstituted solution may initially appear cloudy due to small air bubbles. Do not use the solution if it remains cloudy, contains precipitates, or is discolored. The reconstituted solution should be gently mixed, not shaken. A PATIENT INFORMATION pamphlet is included in each package of Vazaprostan® (alprostadil for injection) cartridges.

Vazaprostan® (alprostadil for injection) should be used immediately after reconstitution. The patient should follow the instructions in the patient information pamphlet to limit the possibility of bacterial contamination. The reconstituted cartridge is designed for one use only and should be discarded after use. The Vazaprostan® (alprostadil for injection) cartridge contains a solid layer or Iyophilized cake of dry white powder approximately 3/8” in thickness. A normal cake may appear cracked or crumbled. If the cartridge is damaged, the cake may shrink in size. Do not use the cartridge if it appears damaged or the cake is substantially reduced in size.

If the dosage prescribed is less than 1 mL of Vazaprostan® (alprostadil for injection) solution, excess solution will be expelled through the needle as the plunger is pushed and the upper rim of the top stopper reaches the correct volume mark for the prescribed dose. The needle must be properly discarded after use; it must not be reused or shared with other persons.

The dose of Vazaprostan® (alprostadil for injection) that is established in the physician's office should not be changed by the patient without consulting the physician. The patient may expect an erection to occur within 5 to 20 minutes. A standard treatment goal is to produce an erection lasting no longer than 1 hour. Vazaprostan® (alprostadil for injection) should be used no more than 3 times per week, with at least 24 hours between each use.

Patients should be aware of possible side effects of therapy with Vazaprostan® (alprostadil for injection) ; the most frequently occurring is penile pain during and/or after injection, usually mild to moderate in severity. A potentially serious adverse reaction with intracavernous therapy is priapism. Accordingly, the patient should be instructed to contact the physician's office immediately or, if unavailable, to seek immediate medical assistance if an erection persists for longer than 6 hours.

The patient should report any penile pain that was not present before or that increased in intensity, as well as the occurrence of nodules or hard tissue in the penis to his physician as soon as possible. As with any injection, infection is possible. Patients should be instructed to report to the physician any penile redness, swelling, tenderness or curvature of the erect penis. The patient must visit the physician's office for regular checkups for assessment of the therapeutic benefit and safety of treatment with Vazaprostan® (alprostadil for injection).

Note: Individuals who are sexually active should be counseled about the protective measures that are necessary to guard against the spread of sexually transmitted diseases, including the human immunodeficiency virus (HIV). Use of intracavernous Vazaprostan® (alprostadil for injection) offers no protection from the transmission of sexually transmitted or blood-borne diseases. The injection of Vazaprostan® (alprostadil for injection) can induce a small amount of bleeding at the site of injection. In patients infected with blood-borne diseases, this could increase the risk of transmission of blood-borne diseases between partners.

Prolonged erections greater than four hours in duration occurred in 4% of all patients treated up to 24 months. The incidence of priapism (erections greater than 6 hours in duration) was < 1% with long-term use for up to 24 months. In the majority of cases, spontaneous detumescence occurred. Pharmacologic intervention and/or aspiration of blood from the corpora was necessary in 1.6% of 311 patients with prolonged erections/priapism. To minimize the chances of prolonged erection or priapism, Vazaprostan® (alprostadil for injection) should be titrated slowly to the lowest effective dose (see DOSAGE AND ADMINISTRATION). The patient must be instructed to immediately report to his prescribing physician or, if unavailable, to seek immediate medical assistance for any erection that persists longer than six hours. If priapism is not treated immediately, penile tissue damage and permanent loss of potency may result.

1. Intracavernous injections of Vazaprostan® (alprostadil for injection) can lead to increased peripheral blood levels of PGE1 and its metabolites, especially in those patients with significant corpora cavernosa venous leakage. Increased peripheral blood levels of PGE1 and its metabolites may lead to hypotension and/or dizziness.
2. Regular follow-up of patients, with careful examination of the penis at the start of therapy and at regular intervals (e.g. 3 months), is strongly recommended to identify any penile changes. The overall incidence of penile fibrosis, including Peyronie's disease, reported in clinical studies up to 24 months with Vazaprostan® (alprostadil for injection) was 7.8%. Treatment with Vazaprostan® (alprostadil for injection) should be discontinued in patients who develop penile angulation, cavernosal fibrosis, or Peyronie's disease. Treatment can be resumed if the penile abnormality subsides.
3. The safety and efficacy of combinations of Vazaprostan® (alprostadil for injection) and other vasoactive agents have not been systematically studied. Therefore, the use of such combinations is not recommended.
4. After injection of the Vazaprostan® (alprostadil for injection) solution, compression of the injection site for five minutes, or until bleeding stops, is necessary. Patients on anticoagulants, such as warfarin or heparin, may have increased propensity for bleeding after intracavernous injection.
5. Underlying treatable medical causes of erectile dysfunction should be diagnosed and treated prior to initiation of therapy with Vazaprostan® (alprostadil for injection).
6. Vazaprostan® (alprostadil for injection) uses a superfine (29 gauge) needle. As with all superfine needles, the possibility of needle breakage exists. Careful instruction in proper patient handling and injection techniques may minimize the potential for needle breakage.
7. The patient should be instructed not to reuse or to share needles or cartridges. As with all prescription medicines, the patient should not allow anyone else to use his medicine.

Long-term carcinogenicity studies have not been conducted. Alprostadil showed no evidence of mutagenicity in three in vitroassays including the AMES bacterial reverse mutation assay, a forward gene mutation assay in Chinese hamster lung (V79) cells, and a chromosome aberration assay in human peripheral lymphocytes. Alprostadil did not produce damage to chromosomes or the mitotic apparatus in the in vivorat micronucleus test.

Alprostadil did not cause any adverse effects on fertility or general reproductive performance when administered intraperitoneally to male or female rats at dose levels from 2 to 200 mcg/kg/day. The high dose of 200 mcg/kg/day is about 300 times the maximum recommended human dose (MRHD) on a body weight basis. The human dose of Vazaprostan® (alprostadil for injection) is < 1 mcg/kg (MRHD is 40 mcg and the calculation assumes a 60 kg subject).

Vazaprostan® (alprostadil for injection) is not indicated for use in women or pediatric patients.

Of the approximately 1,065 patients who entered the in-office dose-titration period in clinical studies, 25% were 65 years or older. In clinical studies, geriatric patients required, on average, higher minimally effective doses and had a higher rate of lack of effect (optimum dose not determined). Overall differences in safety were not observed between these geriatric patients and younger patients. Geriatric patients should be dosed and titrated according to the same DOSAGE AND ADMINISTRATION recommendations as younger patients, and the lowest possible effective dose should always be used.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Limited data are available in regard to Vazaprostan® (alprostadil for injection) overdose in humans. Systemic reactions are uncommon with intracavernous injection of Vazaprostan® (alprostadil for injection). Hypotension occurred in less than 1% of patients treated with Vazaprostan® (alprostadil for injection). A single dose rising tolerance study in healthy volunteers indicated that single intravenous doses of alprostadil from 1 to 120 mcg were well tolerated. Beginning with a 40 mcg bolus intravenous dose, the frequency of drug-related systemic adverse events increased in a dose-dependent manner, characterized mainly by facial flushing.

The primary symptom of an Vazaprostan® (alprostadil for injection) overdose is a prolonged erection or priapism. Because of the potential for tissue hypoxia and possible necrosis, it is strongly recommended to treat an erection lasting more than 6 hours. The patient is strongly encouraged to go to the nearest emergency room if his personal physician is not available.

In the event of an overdose, supportive therapy according to the presence of other symptoms is recommended.

Vazaprostan® (alprostadil for injection) should not be used in patients who have a known hypersensitivity to alprostadil or other prostaglandins, in patients who have conditions that might predispose them to priapism, such as sickle cell anemia or trait, multiple myeloma, or leukemia, or in patients with anatomical deformation of the penis, such as angulation, cavernosal fibrosis, or Peyronie's disease. Patients with penile implants should not be treated with Vazaprostan® (alprostadil for injection).

Vazaprostan® (alprostadil for injection) should not be used in men for whom sexual activity is inadvisable or contraindicated.

Vazaprostan® (alprostadil for injection) should not be used in women and children and is not for use in newborns.

Alprostadil (PGE1 ) is one of the prostaglandins, a family of naturally occurring acidic lipids with various pharmacological effects. Endogenous PGE1 is derived from dihomo-gamma-linolenic acid, a fatty acid found within the phospholipids of cellular membranes. As an endogenous substance, PGE1 exerts its biological effects either directly or indirectly by regulating and modifying the synthesis and effects of other hormones and mediators.

Alprostadil is a smooth muscle relaxant. Precontracted isolated preparations of the human corpus cavernosum, corpus spongiosum and cavernous artery are relaxed by alprostadil. Alprostadil has been shown to bind to specific receptors in human penile tissue. Two types of receptors that differ in their PGE1 binding affinity have been identified. The binding of alprostadil to its receptors is accompanied by an increase in intracellular cAMP levels. Human cavernous smooth muscle cells respond to alprostadil by releasing intracellular calcium into the surrounding medium. Smooth muscle relaxation is associated with a reduction of the cytoplasmic free calcium concentration. Alprostadil also attenuates presynaptic noradrenaline release in the corpus cavernosum which is essential for the maintenance of a flaccid and non-erect penis.

Alprostadil induces erection by relaxation of trabecular smooth muscle and by dilation of cavernous arteries. This leads to expansion of lacunar spaces and entrapment of blood by compressing the venules against the tunica albuginea, a process referred to as the corporal veno-occlusive mechanism.

After reconstitution, PGE1 immediately dissociates from the α-cyclodextrin inclusion complex; the in vivodisposition of both components occurs independently after administration. After intravenous infusion of radiolabeled α-cyclodextrin to healthy volunteers, the radiolabeled components were rapidly eliminated within 24-hours, urine accounting for 81-83% of radioactivity and feces for 0.1%. There was no evidence of significant accumulation of radiolabeled α-cyclodextrin in the body even after 7 days of repeated intravenous injection. After intracavernous administration in monkeys, radiolabeled α-cyclodextrin was rapidly distributed from the injection site with less than 0.1% of the dose remaining in the penis 1 hour after administration. There was no evidence of tissue retention of radiolabeled α-cyclodextrin in monkeys.

Alprostadil Absorption: After intracavernous injection of 20 mcg of Vazaprostan® (alprostadil for injection) in 24 patients with erectile dysfunction, mean systemic plasma concentrations of PGE1 increased from baseline of 0.8 ± 0.6 pg/mL to a peak (Cmax) of 16.8 ± 18.9 pg/mL (corrected for baseline) within 2 to 5 minutes and dropped to endogenous plasma levels within 2 hours (Table 1). The absolute bioavailability of alprostadil estimated from systemic exposure was about 98% as compared to the same dose given by a short-term intravenous infusion.

Distribution: The volume of distribution for PGE1 was not estimated. Approximately 93% of PGE1 found in plasma is protein-bound.

Metabolism: PGE1 is metabolized in the corpus cavernosum after intracavernous administration. PGE1 entering the systemic circulation is rapidly and extensively metabolized in the lungs with a first-pass pulmonary elimination of 60 to 90% of PGE1. Enzymatic oxidation of the C15-hydroxy group followed by reduction of the C13, 14-double bond produces the primary metabolites, 15-keto-PGE1 , 15-keto-PGE0 , and PGE0. 15-keto-PGE1 has only been detected in vitroin homogenized lung preparations, whereas 15-keto-PGE0 and PGE0 have been measured in plasma. Unlike the 15-keto metabolites which are less pharmacologically active than the parent compound, PGE0 is similar in potency to PGE1 in vitrousing isolated animal organs.

After intracavernous injection of 20 mcg of Vazaprostan® (alprostadil for injection) to 24 patients with erectile dysfunction, mean systemic plasma 15-keto-PGE0 levels increased within 7 minutes from endogenous levels of 12.9 ± 11.8 pg/mL to a Cmax of 421 ± 337 pg/mL (corrected for baseline) followed by a decrease to baseline levels in several hours. Mean systemic plasma PGE0 levels increased within 20 minutes from endogenous levels of 0.6 ± 0.5 pg/mL to a Cmax of 3.9 ± 2.3 pg/mL (corrected for baseline) followed by a decrease to baseline levels in several hours.

Excretion: After further degradation of PGE1 by beta and omega oxidation, the main metabolites are excreted primarily in urine (88%) and feces (12%) over 72 hours, and total excretion is essentially complete (92%) within 24 hours after administration. No unchanged PGE1 has been found in the urine and there is no evidence of tissue retention of PGE1 and its metabolites. After intracavernous injection of 20 mcg of Vazaprostan® (alprostadil for injection) in patients with erectile dysfunction, the terminal half-lives (t½) of 15-keto-PGE0 and PGE0 were calculated to be 40.9 ± 16.5 minutes and 63.2 ± 31.1 minutes, respectively. The terminal half-life of PGE1 in healthy volunteers was calculated to be around 9-11 minutes which is consistent with that reported in the literature (8 minutes).

Mean total body clearance of PGE1 in patients with erectile dysfunction was calculated to be around 115 L/min after an intravenous infusion of 20 mcg alprostadil. The above value exceeded cardiac output indicating extensive and rapid elimination of PGE1 in the lungs and/or blood.

Geriatric: The potential effect of age on the pharmacokinetics of alprostadil has not been formally evaluated.

Race: The potential influence of race on the pharmacokinetics of alprostadil has not been formally evaluated.

Hepatic Insufficiency: In a study in symptomatic subjects with impaired hepatic function and age/weight/sex-matched healthy volunteers, 120 mcg of alprostadil was administered by intravenous infusion over 2 hours. The mean Cmax value of PGE1 in hepatically impaired patients was 96% higher than in healthy volunteers. Mean Cmax values of both 15-keto-PGE0 and PGE0 increased 65% as compared to those in healthy volunteers. The terminal half-lives of PGE1 , PGE0 , and 15-keto-PGE0 and plasma albumin levels were similar in patients compared to healthy volunteers. Due to the fact that PGE1 is primarily metabolized in the lung, the observed differences between hepatically impaired subjects and healthy volunteers were not anticipated; the mechanism responsible for the observed discrepancies is not known.

Renal Impairment: In a study in symptomatic subjects with end-stage renal disease undergoing hemodialysis and age/weight/sex-matched healthy volunteers, 120 mcg of alprostadil was administered by intravenous infusion over 2 hours. The mean Cmax value of PGE1 in renally impaired patients was 37% lower as compared to that in healthy volunteers whereas mean Cmax values of 15-keto-PGE0 and PGE0 in these patients increased 104% and 145%, respectively as compared to those in healthy volunteers. The terminal half-lives of PGE1 , PGE0 and 15-keto-PGE0 and plasma albumin levels were similar in these patients vs healthy volunteers. The mechanism responsible for the observed discrepancies between renally impaired subjects and healthy volunteers is not known.

Pulmonary Disease: The pulmonary extraction of alprostadil following intravascular administration was reduced by 15% (66 ± 3.6% vs 78 ± 2.3%) in patients with acute respiratory distress syndrome (ARDS) compared with a group of patients with normal respiratory function who were undergoing cardiopulmonary bypass surgery. Pulmonary clearance was found to vary as a function of cardiac output and pulmonary intrinsic clearance in a group of 14 patients with ARDS or at risk of developing ARDS following trauma or sepsis. In this study, the pulmonary extraction efficiency of alprostadil ranged from subnormal (11%) to normal (90%), with an overall mean of 67%.

Drug-Drug Interactions: In clinical trials, concomitant use of agents such as antihypertensive drugs, diuretics, antidiabetic agents (including insulin), or nonsteroidal anti-inflammatory drugs had no apparent effect on the efficacy or safety of Vazaprostan® (alprostadil for injection).

Aspirin, Warfarin, Digoxin, Glyburide: Several drug-drug interaction studies have been conducted with alprostadil alone or in combination with aspirin, digoxin or warfarin in healthy volunteers and with glyburide in subjects with stable, non-insulin dependent diabetes mellitus. The pharmacokinetic profiles of aspirin, warfarin, digoxin, and glyburide were not affected by concomitant administration of alprostadil. There were no clinically important changes or trends in pharmacodynamic parameters for these drugs.

Heparin: The pharmacokinetic and pharmacodynamic interaction between alprostadil intravenous infusion, 90 mcg over 3 hours, and heparin (5,000 IU) was evaluated in 12 healthy volunteers. Alprostadil had a significant effect on the pharmacodynamics of heparin resulting in a 140% increase in partial thromboplastin time and a 120% increase in thrombin time. Therefore, caution should be exercised with concomitant administration of heparin and Vazaprostan® (alprostadil for injection).

TABLE 1

In two studies [Protocol numbers KU-620-001 (Study 1) and KU-620-002 (Study 2)], the safety and efficacy of Vazaprostan® (alprostadil for injection) were evaluated in 347 men with a diagnosis of erectile dysfunction due to vasculogenic, neurogenic and/or mixed etiology. Each study consisted of three phases: an in-office dose-titration phase, a two-week double-blind cross-over phase at home, and an open-label at home treatment phase that lasted for 12 months (Study 1) or six months (Study 2).

During the dose-titration phase, individualized optimum doses of Vazaprostan® (alprostadil for injection) were established. Erectile response was measured by the Buckling Test to assess axial penile rigidity. A positive Buckling Test was achieved if the erect penis was able to support an axial load of 1.0 kg without buckling of the penile shaft. During the subsequent two-week double-blind, cross-over phase, patients self-injected Vazaprostan® (alprostadil for injection) or placebo at home. Thereafter, patients continued to perform self-injections of open-label Vazaprostan® (alprostadil for injection) for six or 12 months, and the occurrence of an erection sufficient for sexual intercourse was documented following each injection.

Study 1: One hundred fourteen men with a mean age of 53 years (range 22 to 65 years) were enrolled in the first phase. The mean optimum dose was 13.8 mcg (range 1 to 20 mcg). Seventy-six percent (87/114) of patients had an erection with a positive penile Buckling Test. Among the 71% (81/114) of patients who entered the placebo-controlled phase, an erection sufficient for sexual intercourse was achieved in 74% (60/81) of patients following Vazaprostan® (alprostadil for injection) injection compared to 7% (6/81) of patients following placebo injection. The mean duration of erection following Vazaprostan® (alprostadil for injection) was 56.9 minutes compared to 4.0 minutes following placebo. Among the 65% (74/114) of patients who entered the open-label treatment phase, the mean rate of response with an erection sufficient for sexual intercourse was 88.9% through 12 months. The average dose of Vazaprostan® (alprostadil for injection) remained essentially unchanged throughout the study duration.

Study 2: Two hundred thirty-three men with a mean age of 59.8 years (range 23 to 74 years) were enrolled in the first phase. The mean optimum dose was 25.9 mcg (range 1 to 40 mcg). Seventy-three percent (17½33) of patients had an erection with a positive penile Buckling Test. Among the 60% (14½33) of patients who entered the placebo-controlled phase, an erection sufficient for sexual intercourse was achieved in 73% (103/141) of patients following Vazaprostan® (alprostadil for injection) injection compared to 13% (18/141) of patients following placebo injection. The mean duration of erection following Vazaprostan® (alprostadil for injection) was 59.0 minutes compared to 7.6 minutes following placebo. Among the 60% (139/233) of patients who entered the open-label treatment phase, the mean rate of response with an erection sufficient for intercourse was 85.3% through six months. The average dose of Vazaprostan® (alprostadil for injection) remained essentially unchanged throughout the study duration.

Name of the medicinal product

Qualitative and quantitative composition

Special warnings and precautions for use

Prolonged erections greater than four hours in duration occurred in 4% of all patients treated up to 24 months. The incidence of priapism (erections greater than 6 hours in duration) was < 1% with long-term use for up to 24 months. In the majority of cases, spontaneous detumescence occurred. Pharmacologic intervention and/or aspiration of blood from the corpora was necessary in 1.6% of 311 patients with prolonged erections/priapism. To minimize the chances of prolonged erection or priapism, Vazaprostan® (alprostadil for injection) should be titrated slowly to the lowest effective dose (see DOSAGE AND ADMINISTRATION). The patient must be instructed to immediately report to his prescribing physician or, if unavailable, to seek immediate medical assistance for any erection that persists longer than six hours. If priapism is not treated immediately, penile tissue damage and permanent loss of potency may result.

1. Intracavernous injections of Vazaprostan® (alprostadil for injection) can lead to increased peripheral blood levels of PGE1 and its metabolites, especially in those patients with significant corpora cavernosa venous leakage. Increased peripheral blood levels of PGE1 and its metabolites may lead to hypotension and/or dizziness.
2. Regular follow-up of patients, with careful examination of the penis at the start of therapy and at regular intervals (e.g. 3 months), is strongly recommended to identify any penile changes. The overall incidence of penile fibrosis, including Peyronie's disease, reported in clinical studies up to 24 months with Vazaprostan® (alprostadil for injection) was 7.8%. Treatment with Vazaprostan® (alprostadil for injection) should be discontinued in patients who develop penile angulation, cavernosal fibrosis, or Peyronie's disease. Treatment can be resumed if the penile abnormality subsides.
3. The safety and efficacy of combinations of Vazaprostan® (alprostadil for injection) and other vasoactive agents have not been systematically studied. Therefore, the use of such combinations is not recommended.
4. After injection of the Vazaprostan® (alprostadil for injection) solution, compression of the injection site for five minutes, or until bleeding stops, is necessary. Patients on anticoagulants, such as warfarin or heparin, may have increased propensity for bleeding after intracavernous injection.
5. Underlying treatable medical causes of erectile dysfunction should be diagnosed and treated prior to initiation of therapy with Vazaprostan® (alprostadil for injection).
6. Vazaprostan® (alprostadil for injection) uses a superfine (29 gauge) needle. As with all superfine needles, the possibility of needle breakage exists. Careful instruction in proper patient handling and injection techniques may minimize the potential for needle breakage.
7. The patient should be instructed not to reuse or to share needles or cartridges. As with all prescription medicines, the patient should not allow anyone else to use his medicine.

Long-term carcinogenicity studies have not been conducted. Alprostadil showed no evidence of mutagenicity in three in vitroassays including the AMES bacterial reverse mutation assay, a forward gene mutation assay in Chinese hamster lung (V79) cells, and a chromosome aberration assay in human peripheral lymphocytes. Alprostadil did not produce damage to chromosomes or the mitotic apparatus in the in vivorat micronucleus test.

Alprostadil did not cause any adverse effects on fertility or general reproductive performance when administered intraperitoneally to male or female rats at dose levels from 2 to 200 mcg/kg/day. The high dose of 200 mcg/kg/day is about 300 times the maximum recommended human dose (MRHD) on a body weight basis. The human dose of Vazaprostan® (alprostadil for injection) is < 1 mcg/kg (MRHD is 40 mcg and the calculation assumes a 60 kg subject).

Vazaprostan® (alprostadil for injection) is not indicated for use in women or pediatric patients.

Of the approximately 1,065 patients who entered the in-office dose-titration period in clinical studies, 25% were 65 years or older. In clinical studies, geriatric patients required, on average, higher minimally effective doses and had a higher rate of lack of effect (optimum dose not determined). Overall differences in safety were not observed between these geriatric patients and younger patients. Geriatric patients should be dosed and titrated according to the same DOSAGE AND ADMINISTRATION recommendations as younger patients, and the lowest possible effective dose should always be used.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Dosage (Posology) and method of administration

The dosage range of Vazaprostan® (alprostadil for injection) for the treatment of erectile dysfunction is 1 to 40 mcg. The intracavernous injection should be given over a 5 to 10 second interval. In a study with a dose range of 1 to 20 mcg of Vazaprostan® (alprostadil for injection) , the mean dose was 10.7 mcg at the end of the dose titration period. In two studies with a dose range of 1 to 40 mcg of Vazaprostan® (alprostadil for injection) , the mean dose was 21.9 mcg at the end of the dose titration period. Doses greater than 40 mcg have not been studied. A ½ inch, 27 to 30 gauge needle is generally recommended for the intracavernous injection. The patient is advised not to exceed the optimum Vazaprostan® (alprostadil for injection) dose which was determined in the doctor's office. The lowest possible effective dose should always be used.

Erectile Dysfunction of Vasculogenic, Psychogenic, or Mixed Etiology: Dosage titration should be initiated at 2.5 micrograms of alprostadil. If there is a partial response, the dose may be increased by 2.5 micrograms to a dose of 5 micrograms and then in increments of 5 to 10 micrograms, depending upon erectile response, until the dose that produces an erection suitable for intercourse and not exceeding a duration of 1 hour is reached. If there is no response to the initial 2.5-microgram dose, the second dose may be increased to 7.5 micrograms, followed by increments of 5 to 10 micrograms. The patient must stay in the physician's office until complete detumescence occurs. It there is no response, then the next higher dose may be given within 1 hour. If there is a response, then there should be at least a 1-day interval before the next dose is given.

Erectile Dysfunction of Pure Neurogenic Etiology (Spinal Cord Injury): Dosage titration should be initiated at 1.25 micrograms of alprostadil. The dose may be increased by 1.25 micrograms to a dose of 2.5 micrograms, followed by an increment of 2.5 micrograms to a dose of 5 micrograms, and then in 5-microgram increments until the dose that produces an erection suitable for intercourse and not exceeding a duration of 1 hour is reached. The patient must stay in the physician's office until complete detumescence occurs. If there is no response, then the next higher dose may be given within 1 hour. If there is a response, then there should be at least a 1-day interval before the next dose is given.

The first injections of Vazaprostan® (alprostadil for injection) must be done at the physician's office by medically trained personnel. Self-injection therapy by the patient can be started only after the patient is properly instructed and well trained in the self-injection technique. The physician should instruct the patient to discard any needles which become bent during the self-injection procedure as these needles may break. The physician should make a careful assessment of the patient's skills and competence with the self-injection procedure. The intracavernous injection must be done under sterile conditions. The site of injection is usually along the lateral aspect of the proximal third of the penis. Visible veins should be avoided. The side of the penis that is injected and the site of injection must be alternated. The injection site must be cleansed with an alcohol swab before injection.

The dose of Vazaprostan® (alprostadil for injection) that is selected for self-injection treatment should provide the patient with an erection that is satisfactory for sexual intercourse and that is maintained for no longer than 1 hour. If the duration of erection is longer than 1 hour, the dose of Vazaprostan® (alprostadil for injection) should be reduced. The lowest effective dose should be used at home. Self-injection therapy for use at home should be initiated at the dose that was determined in the physician's office. Dose adjustment may be required and should be made only after consultation with the physician.

Careful and continuous follow-up of the patient while in the self-injection program must be exercised. This is especially true for the initial self-injections, since adjustments in the dose of Vazaprostan® (alprostadil for injection) may be needed. The recommended frequency of injection is no more than 3 times weekly, with at least 24 hours between each dose. The reconstituted Vazaprostan® (alprostadil for injection) cartridge and needle are intended for single use only and should be discarded after use. The user should be instructed in the proper disposal of the needles and cartridges.

While on self-injection treatment, it is recommended that the patient visit the prescribing physician's office every 3 months. At that time, the efficacy and safety of the therapy should be assessed, and the dose of Vazaprostan® (alprostadil for injection) should be adjusted, if needed.

The patient is instructed to follow the enclosed PATIENT INFORMATION pamphlet.

The Vazaprostan® (alprostadil for injection) injection device is used to reconstitute the single-dose, dual-chamber cartridge. The plunger is used to force the sterile 0.9% sodium chloride (1.075 mL) in one chamber into the chamber containing alprostadil. After reconstitution, the Vazaprostan® (alprostadil for injection) injection device is used to administer the intracavernous injection of alprostadil. The reusable Vazaprostan® (alprostadil for injection) injection device is for use only with the cartridges and needles included in the Vazaprostan® (alprostadil for injection) Cartridge Packs.

Prepare the Vazaprostan® (alprostadil for injection) solution immediately before use. Do not administer unless solution is clear. Do not add any drugs or solutions to the Vazaprostan® (alprostadil for injection) solution. Discard any unused solution remaining in the cartridge. The reconstituted solution should not be stored.

The Vazaprostan® (alprostadil for injection) cartridge contains a solid layer or lyophilized cake of dry white powder approximately 3/8” in thickness. A normal cake may appear cracked or crumbled. If the cartridge is damaged, the cake may shrink in size. Do not use the cartridge if it appears damaged or the cake is substantially reduced in size.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration. The reconstituted solution may initially appear cloudy due to small air bubbles. Do not use the solution if it remains cloudy, contains precipitates, or is discolored.

CAUTION: Do not reuse any solution remaining in the cartridge due to the possibility of bacterial contamination.

Vazaprostan® (alprostadil for injection) is given as an intracavernous injection over a 5 to 10 second interval. See PATIENT INFORMATION for Vazaprostan® (alprostadil for injection).

The single-dose, dual-chamber cartridge should be reconstituted only when it is certain that the patient is ready to administer the drug. The reconstituted drug solution should be used immediately after reconstitution. Any solution remaining in the cartridge should be discarded.