Flector

Overdose

Symptoms following acute NSAID overdosages have been typically limited to lethargy, drowsiness, nausea, vomiting, and epigastric pain, which have been generally reversible with supportive care. Gastrointestinal bleeding has occurred. Hypertension, acute renal failure, respiratory depression, and coma have occurred, but were rare.

Manage patients with symptomatic and supportive care following an NSAID overdosage. There are no specific antidotes. Forced diuresis, alkalinization of urine, hemodialysis, or hemoperfusion may not be useful due to high protein binding.

For additional information about overdosage treatment contact a poison control center (1- 800-222-1222).

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Undesirable effects

The following adverse reactions are discussed in greater detail in other sections of the labeling:

• Cardiovascular Thrombotic Events
• GI Bleeding, Ulceration and Perforation
• Hepatotoxicity
• Hypertension
• Heart Failure and Edema
• Renal Toxicity and Hyperkalemia
• Anaphylactic Reactions
• Serious Skin Reactions
• Hematologic Toxicity

Because clinical trials are conducted under widely varying conditions, adverse reaction ratesobserved in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In controlled trials during the premarketing development of FLECTOR PATCH, approximately 600 patients with minor sprains, strains, and contusions were treated with FLECTOR PATCH for up to two weeks.

In the controlled trials, 3% of patients in both the FLECTOR PATCH and placebo patch groups discontinued treatment due to an adverse event. The most common adverse events leading to discontinuation were application site reactions, occurring in 2% of both the FLECTOR PATCH and placebo patch groups. Application site reactions leading to dropout included pruritus, dermatitis, and burning.

Localized Reactions

Overall, the most common adverse events associated with FLECTOR PATCH treatment were skin reactions at the site of treatment. Table 1 lists all adverse events, regardless of causality, occurring in ≥ 1% of patients in controlled trials of FLECTOR PATCH. A majority of patients treated with FLECTOR PATCH had adverse events with a maximum intensity of “mild” or “moderate.”

Table 1: Common Adverse Events (by body system and preferred term) in ≥ 1% of Patients treated with FLECTOR PATCH or Placebo Patch

Foreign labeling describes that dermal allergic reactions may occur with FLECTOR PATCH treatment. Additionally, the treated area may become irritated or develop itching, erythema, edema, vesicles, or abnormal sensation.

Pharmacokinetic properties

Following a single application of the FLECTOR PATCH on the upper inner arm, peak plasma concentrations of diclofenac (range 0.7 – 6 ng/mL) were noted between 10 – 20 hours of application. Plasma concentrations of diclofenac in the range of 1.3 – 8.8 ng/mL were noted after five days with twice-a-day FLECTOR PATCH application.

Systemic exposure (AUC) and maximum plasma concentrations of diclofenac, after repeated dosing for four days with FLECTOR PATCH, were lower ( < 1%) than after a single oral 50mg diclofenac sodium tablet.

The pharmacokinetics of FLECTOR PATCH has been tested in healthy volunteers at rest or undergoing moderate exercise (cycling 20 min/h for 12 h at a mean HR of 100.3 bpm). No clinically relevant differences in systemic absorption were observed, with peak plasma concentrations in the range of 2.2 – 8.1 ng/mL while resting, and 2.7 – 7.2 ng/mL during exercise.

Diclofenac has a very high affinity ( > 99%) for human serum albumin. Diclofenac diffuses into and out of the synovial fluid. Diffusion into the joint occurs when plasma levels are higher than those in the synovial fluid, after which the process reverses and synovial fluid levels are higher than plasma levels. It is not known whether diffusion into the joint plays a role in the effectiveness of diclofenac.

Metabolism

Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'-hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy diclofenac. The major diclofenac metabolite, 4'hydroxy-diclofenac, has very weak pharmacologic activity. The formation of 4'-hydroxy diclofenac is primarily mediated by CPY2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CPY2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy and 3'-hydroxy- diclofenac.

Excretion

The plasma elimination half-life of diclofenac after application of FLECTOR PATCH is approximately 12 hours. Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Little or no free unchanged diclofenac is excreted in the urine. Approximately 65% of the dose is excreted in the urine and approximately 35% in the bile as conjugates of unchanged diclofenac plus metabolites.

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Fertility, pregnancy and lactation

Pregnancy Category C prior to 30 weeks gestation; Category D starting 30 weeks gestation.

Use of NSAIDs, including FLECTOR PATCH, during the third trimester of pregnancy increases the risk of premature closure of the fetal ductus arteriosus. Avoid use of NSAIDs, including FLECTOR PATCH, in pregnant women starting at 30 weeks of gestation (third trimester).

There are no adequate and well-controlled studies of FLECTOR PATCH in pregnant women. Data from observational studies regarding potential embryofetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive. In the general U.S. population, all clinically recognized pregnancies, regardless of drug exposure, have a background rate of 2-4% for major malformations, and 15-20% for pregnancy loss. In animal reproduction studies, diclofenac epolamine administered orally to pregnant rats and rabbits during the period of organogenesis produced embryotoxicity at approximately 3 and 7 times, respectively, the topical exposure from the maximum recommended human dose (MRHD) of FLECTOR PATCH. In rats, increased incidences of skeletal anomalies and maternal toxicity were also observed at this dose. Diclofenac epolamine administered orally to both male and female rats prior to mating and throughout the mating period, and during gestation and lactation in females produced embryotoxicity at doses approximately 3 and 7 times, respectively, the topical exposure from the MRHD.

Based on animal data, prostaglandins have been shown to have an important role in endometrial vascular permeability, blastocyst implantation, and decidualization. In animal studies, administration of prostaglandin synthesis inhibitors such as diclofenac, resulted in increased pre- and post-implantation loss.

Labor or Delivery

There are no studies on the effects of FLECTOR PATCH during labor or delivery. In animal studies, NSAIDS, including diclofenac, inhibit prostaglandin synthesis, cause delayed parturition, and increase the incidence of stillbirth.

Animal data

Pregnant Sprague Dawley rats were administered 1, 3, or 6 mg/kg diclofenac epolamine via oral gavage daily from gestation days 6 to 15. Maternal toxicity, embryotoxicity, and increased incidence of skeletal anomalies were noted with 6 mg/kg/day diclofenac epolamine, which corresponds to 3 times the maximum recommended daily exposure in humans based on a body surface area comparison. Pregnant New Zealand White rabbits were administered 1, 3, or 6 mg/kg diclofenac epolamine via oral gavage daily from gestation days 6 to 18. No maternal toxicity was noted; however, embryotoxicity was evident at 6 mg/kg/day group which corresponds to 7 times the maximum recommended daily exposure in humans based on a body surface area comparison.

Male rats were orally administered diclofenac epolamine (1, 3, 6 mg/kg) for 60 days prior to mating and throughout the mating period, and females were given the same doses 14 days prior to mating and through mating, gestation, and lactation. Embryotoxicity was observed at 6 mg/kg diclofenac epolamine (3 times the maximum recommended daily exposure in humans based on a body surface area comparison), and was manifested as an increase in early resorptions, post-implantation losses, and a decrease in live fetuses. The number of live born and total born were also reduced as was F1 postnatal survival, but the physical and behavioral development of surviving F1 pups in all groups was the same as the deionized water control, nor was reproductive performance adversely affected despite a slight treatment-related reduction in body weight.

Interaction with other medicinal products and other forms of interaction

The following adverse reactions are discussed in greater detail in other sections of the labeling:

• Cardiovascular Thrombotic Events
• GI Bleeding, Ulceration and Perforation
• Hepatotoxicity
• Hypertension
• Heart Failure and Edema
• Renal Toxicity and Hyperkalemia
• Anaphylactic Reactions
• Serious Skin Reactions
• Hematologic Toxicity

Because clinical trials are conducted under widely varying conditions, adverse reaction ratesobserved in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In controlled trials during the premarketing development of FLECTOR PATCH, approximately 600 patients with minor sprains, strains, and contusions were treated with FLECTOR PATCH for up to two weeks.

In the controlled trials, 3% of patients in both the FLECTOR PATCH and placebo patch groups discontinued treatment due to an adverse event. The most common adverse events leading to discontinuation were application site reactions, occurring in 2% of both the FLECTOR PATCH and placebo patch groups. Application site reactions leading to dropout included pruritus, dermatitis, and burning.

Localized Reactions

Overall, the most common adverse events associated with FLECTOR PATCH treatment were skin reactions at the site of treatment. Table 1 lists all adverse events, regardless of causality, occurring in ≥ 1% of patients in controlled trials of FLECTOR PATCH. A majority of patients treated with FLECTOR PATCH had adverse events with a maximum intensity of “mild” or “moderate.”

Table 1: Common Adverse Events (by body system and preferred term) in ≥ 1% of Patients treated with FLECTOR PATCH or Placebo Patch

Foreign labeling describes that dermal allergic reactions may occur with FLECTOR PATCH treatment. Additionally, the treated area may become irritated or develop itching, erythema, edema, vesicles, or abnormal sensation.

See Table 2 for clinically significant drug interactions with diclofenac.

Table 2: Clinically Significant Drug Interactions with Diclofenac