Treatment is symptomatic. Cardiac rhythm disorders, including Torsades de Pointes, have been reported following overdose of pentamidine isetionate.
The drug should not be administered to patients with a known hypersensitivity to pentamidine.
Pentamidine isetionate solution should not be mixed with any injection solutions other than Water for Injections BP, Glucose Intravenous Infusion BP and 0.9% (normal) Sodium Chloride Injection BP.
Adverse reactions frequency is defined using the following convention:
Very common (> 1/10); common (> 1/100 to < 1/10); uncommon (> 1/1,000 to < 1/100); rare (> 1/10,000 to < 1/1,000); very rare (< 1/10,000), not known (cannot be estimated from the available data).
Parenteral Route
Blood and lymphatic system disorders:
Common: leucopenia, thrombocytopenia, anaemia
Immune system disorders:
Frequency not know: Hypersensitivity reactions, including anaphylactic reactions and anaphylactic shock, angioedema.
Metabolism and nutrition disorders:
Very common: azotemia
Common: hypoglycaemia, hyperglycaemia, hyperkalaemia, hypocalcaemia, hypomagnesemia
Nervous system disorders:
Common: syncope, dizziness
Frequency not know: Extremity paraesthesia as well as facial and perioral hypoesthesia have been reported with IV administration of pentamidine, both in children and adults. The cases occurred during or shortly after the IV infusion and resolved after completion or interruption of the infusion.
Cardiac disorders:
Rare: QT interval prolongation, cardiac arrhythmia
Frequency not known: Torsades de Pointes, bradycardia
Vascular disorders:
Common: hypotension, flushing
Gastrointestinal disorders:
Common: nausea and vomiting, taste disturbance
Rare: pancreatitis
Hepatobiliary disorders:
Common: abnormal liver function tests
Skin and subcutaneous tissue disorders:
Common: rash
Frequency not known: Stevens-Johnson syndrome
Renal and urinary disorders:
Very common: acute renal failure, macroscopic haematuria
General disorders and administration site conditions:
Very common: local reactions ranging in severity from discomfort and pain to induration, abscess formation and muscle necrosis.
Frequency not known: rhabdomyolysis has been reported following intramuscular administration
Inhalation Route :
Immune system disorders:
Frequency not know: Hypersensitivity reactions, including anaphylactic reactions and anaphylactic shock, angioedema.
Metabolism and nutrition disorders
Frequency not known: hypoglycaemia
Nervous system disorders
Frequency not known: light-headedness
Cardiac disorders:
Frequency not know: bradycardia
Vascular disorders:
Frequency not known: hypotension
Respiratory, thoracic and mediastinal disorders:
Common: local reactions ranging in severity from cough, shortness of breath, wheezing, bronchospasms, particularly in patients with a history of smoking or asthma, which can usually be controlled by prior use of bronchodilators
Rare: eosinophilic pneumonia
Frequency not known: pneumothorax in patients presenting a history of Pneumocystis carinii pneumonia.
Gastrointestinal disorders:
Common: taste disturbance, nausea
Frequency not known: acute pancreatitis
Skin and subcutaneous tissue disorders:
Frequency not known: rash
Renal and urinary disorders:
Frequency not known: renal insufficiency
General disorders and administration site conditions:
Frequency not known: fever, decrease in appetite, fatigue
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard
No additional data of relevance to the prescriber
Pentamidine is indicated in the treatment of:
- Pneumonia due to Pneumocystis carinii (PCP)
- Cutaneous leishmaniasis
- Early phase African sleeping sickness caused by Trypanosoma gambiense.
- Prevention of Pneumocystis carinii pneumonia in patients infected by the human immunodeficiency virus (HIV) who have experienced a previous episode of PCP.
Pharmacotherapeutic group: Antiprotozoals, other agents against leishmaniasis and trypanosomiasis, ATC Code: P01CX01
Pentamidine isetionate is an aromatic diamine. It is an antiprotozoal agent which acts by interfering with DNA and folate transformation, and by the inhibition of RNA and protein synthesis.
After intravenous infusion, plasma levels of pentamidine fall rapidly during the first two hours to one twentieth of peak levels, followed by a much slower decline thereafter. After intramuscular administration, the apparent volume of distribution of pentamidine is significantly greater (>3 times) than that observed following intravenous administration.
Elimination of half-lives after parenteral administration were estimated to be about 6 hours after intravenous infusion in patients with a normal renal function. The elimination of half-life following intramuscular injection was found to be about 9 hours.
Following parenteral administration, pentamidine appears to be widely distributed in the body and probably accumulates in tissue, particularly the liver and kidney. Only a small amount is excreted unchanged in the urine.
When administered by the use of a nebuliser, human kinetic studies revealed significant differences when compared to parenteral administration. Aerosol administration resulted in a 10-fold increase in bronchial alveolar lavage (BAL) supernatant fluid and an 80-fold increase in BAL sediment concentrations in comparison with those seen with equivalent intravenous doses.
Limited data suggests that the half-life of pentamidine in BAL fluid is greater than 10 to 14 days. Peak plasma concentrations after inhalation therapy were found to be approximately 10% of those observed with equivalent intramuscular doses and less than 5% of those observed following intravenous administration. This suggests that systemic effects by the inhalation route are less likely.
Long term pulmonary parenchymal effects of aerosolised pentamidine are not known. Lung volume and alveolar capillary diffusion, however, have not been shown to be affected by high doses of pentamidine administered by inhalation to AIDS patients.
Pentamidine isetionate should be used with particular caution in patients with hepatic and/or renal dysfunction, hypertension or hypotension, hyperglycaemia or hypoglycaemia, leucopenia, thrombocytopenia or anaemia.
Fatalities due to severe hypotension, hypoglycaemia, acute pancreatitis and cardiac arrhythmias have been reported in patients treated with pentamidine isetionate, by both the intramusclar and intravenous routes. Baseline blood pressure should be established and patients should receive the drug lying down. Blood pressure should be closely monitored during administration and at regular intervals until treatment is concluded.
Therefore patients receiving pentamidine by inhalation should be closely monitored for the development of severe adverse reactions.
Bronchospasm has been reported to occur following the use of nebuliser. This has been particularly noted in patients who have a history of smoking or asthma. This can be controlled by prior use of bronchodilators.
Pentamidine isetionate may prolong the QT interval. Cardiac arrhythmias indicative of QT prolongation, such as Torsades de Pointes, have been reported in isolated cases with administration of pentamidine isetionate. Therefore, pentamidine isetionate should be used with care in patients with conditions known to increase the proarrhythmic risk, including patients with long QT syndrome, cardiac disease (e.g. coronary heart disease, heart failure) a history of ventricular arrhythmias, uncorrected hypokalaemia and/or hypomagnesaemia, bradycardia (<50 bpm), or during concomitant administration of pentamidine isetionate with QT prolonging agents.
Particular caution is necessary if the QTc exceeds 500 msec whilst receiving pentamidine isetionate therapy, continuous cardiac monitoring should be considered in this case.
Should the QTc interval exceed 550 msec then an alternative regimen should be considered
Laboratory monitoring : The following tests should be carried out before, during and after therapy by the parenteral route:
| I) | Blood urea, nitrogen and serum creatinine daily during therapy. |
| II) | Complete blood and platelet counts daily during therapy. |
| III) | Fasting blood glucose measurements daily during therapy, and at regular intervals after completion of therapy. Hyperglycaemia and diabetes mellitus, with or without preceding hypoglycaemia have occurred up to several months after cessation of therapy. |
| IV) | Liver function tests (LFTS) including bilirubin, alkaline phosphatase, aspartate aminotransferase (AST/GOT), and alkaline aminotransferase (ALT/GPT). If baseline measurements are normal and remain so during therapy, test weekly. When there is baseline elevation in LFTS and/or LFTS increase during therapy, continue monitoring weekly unless the patient is on other hepatotoxic agents, when monitoring every 3-5 days is appropriate. |
| V) | Serum calcium, test weekly. Serum magnesium, test twice weekly. |
| VI) | Electrocardiograms at regular intervals. |
| VII) | Urine analysis and serum electrolytes daily during therapy. |
The benefit of aerosolised pentamidine therapy in patients at high risk of a pneumothorax should be weighed against the clinical consequences of such a manifestation.
Pentamidine has no known effect on the ability to drive and use machines.
Considering the risk of dizziness, one should be careful.
All indications can be treated by deep intramuscular injection or intravenous injection.
Pentamidine powder is reconstituted before use with Water for Injections. For intravenous use the required dose of pentamidine isetionate is diluted further in 50-250ml of glucose intravenous infusion or 0.9% (normal) Sodium Chloride Injection.
The following dosage regimens are recommended for adults, children and infants.
Treatment:
Pneumocystis carinii pneumonia:
The preferred route of administration is by slow IV infusion, 4 mg/kg bodyweight of pentamidine isetionate once daily for at least 14 days. The IM route is not recommended for the treatment of PCP.
Leishmaniasis
Cutaneous: 4 mg/kg bodyweight, every other day for 3 doses by IM or IV injection.
Trypanosomiasis :
4mg/kg bodyweight of pentamidine isetionate per day for 7 days. The preferred route is by deep IM injection. Otherwise slow IV infusion over 60-120 minutes may be used.
Prevention:
In the prophylaxis of P. carinii pneumonia, administration is by the inhalation route; the adult dosage is 300 mg every 4 weeks or 150mg every 2 weeks.
Dissolve the contents of one Pentam vial (300 mg pentamidine isetionate) in 4-6 ml water for injections and the resultant solution should be administered by a suitable nebuliser.
Elderly
There are no specific dosage recommendations for the elderly.
Renal impairment
In renal failure the following recommendations are made for a creatinine clearance of less than 10ml/min.:
- Pneumocystis carinii pneumonia:
In life threatening cases, 4 mg/kg bodyweight once daily for 7 to 10 days, then 4 mg/kg bodyweight on alternate days, to complete the course of at least 14 doses. In less severe cases, 4 mg/kg bodyweight on alternate days, to complete the course of at least 14 doses.
- Leishmaniasis:
No dosage reductions are necessary
- Trypanosomiasis:
No dosage reductions are necessary
- Hepatic impairment:
No specific dosage recommendations.
This product should be reconstituted in a fume cupboard. Store the dry product below 30°C. Store dilute reconstituted drug solutions between 2-8°C, and discard all unused portions within 24 hours of preparation. Concentrated solutions for administration by the inhalation or intramuscular routes should be used immediately.
After reconstitution with Water for Injections, Pentam should not be mixed with any injection solutions other than Glucose Intravenous Infusion 5% and 0.9% (normal) Sodium Chloride Injection.
The optimal particle size for alveolar deposition is between 1 and 2 microns.
The freshly prepared solution should be administered by inhalation using a suitable nebuliser such as a Respirgard II (trade mark of Marquest Medical Products Inc.), Modified Acorn system 22 (trade mark of Medic-Aid) or an equivalent device with either a compressor or piped oxygen at a flow rate of 6 to 10 Litres/Minute.
The nebuliser should be used in a vacated, well ventilated room. Only staff wearing adequate protective clothing (mask, goggles, gloves) should be in the room when nebulisers are being used.
A suitable well fitted one-way system should be employed such that the nebuliser stores the aerosolised drug during exhalations and disperses exhaled pentamidine into a reservoir. A filter should be fitted to the exhaust line to reduce atmospheric pollution. It is advisable to use a suitable exhaust tube which vents directly through a window to the external atmosphere. Care should be taken to ensure that passers-by will not be exposed to the exhaust.
All bystanders including medical personnel, women of child bearing potential, pregnant women, children, and people with a history of asthma, should avoid exposure to atmospheric pentamidine resulting from nebuliser usage.
Dosage equivalence : 4 mG of pentamidine isetionate contains 2.3 mG pentamidine base; 1 mg of pentamidine base is equivalent to 1.74 mG pentamidine isetionate.
Displacement value : 300 mG of pentamidine isetionate displace approximately 0.15 ml of water.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
