The following adverse reactions have been identified during post approval use of finasteride tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:
Hypersensitivity Reaction: hypersensitivity reactions such as rash, pruritus, urticaria, and angioedema (including swelling of the lips, tongue, throat, and face);
Reproductive System: sexual dysfunction that continued after discontinuation of treatment, including erectile dysfunction, libido disorders, ejaculation disorders, and orgasm disorders; male infertility and/or poor seminal quality (normalization or improvement of seminal quality has been reported after discontinuation of finasteride); testicular pain. [See Adverse Reactions (6.1).]
Neoplasms: male breast cancer;
Breast disorders: breast tenderness and enlargement;
Nervous System/Psychiatric: depression
No drug interactions of clinical importance have been identified. Finasteride does not appear to affect the cytochrome P450-linked drug-metabolizing enzyme system. Compounds that have been tested in man include antipyrine, digoxin, propranolol, theophylline, and warfarin and no clinically meaningful interactions were found.
Although specific interaction studies were not performed, finasteride doses of 1 mg or more were concomitantly used in clinical studies with acetaminophen, acetylsalicylic acid, α-blockers, analgesics, angiotensin-converting enzyme (ACE) inhibitors, anticonvulsants, benzodiazepines, beta blockers, calcium-channel blockers, cardiac nitrates, diuretics, H antagonists, HMG-CoA reductase 2 inhibitors, prostaglandin synthetase inhibitors (also referred to as NSAIDs), and quinolone anti-infectives without evidence of clinically significant adverse interactions.
Pregnancy Category X [see Contraindications (4)].
Finasteride tablets is contraindicated for use in women who are or may become pregnant. Finasteride tablets is a Type II 5α-reductase inhibitor that prevents conversion of testosterone to 5αdihydrotestosterone (DHT), a hormone necessary for normal development of male genitalia. In animal studies, finasteride caused abnormal development of external genitalia in male fetuses. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the male fetus.
Abnormal male genital development is an expected consequence when conversion of testosterone to 5α- dihydrotestosterone (DHT) is inhibited by 5α-reductase inhibitors. These outcomes are similar to those reported in male infants with genetic 5α-reductase deficiency. Women could be exposed to finasteride through contact with crushed or broken finasteride tablets or semen from a male partner taking finasteride tablets. With regard to finasteride exposure through the skin, finasteride tablets are coated and will prevent skin contact with finasteride during normal handling if the tablets have not been crushed or broken. Women who are pregnant or may become pregnant should not handle crushed or broken finasteride tablets because of possible exposure of a male fetus. If a pregnant woman comes in contact with crushed or broken finasteride tablets the contact area should be washed immediately with soap and water. With regard to potential finasteride exposure through semen, a study has been conducted in men receiving finasteride tablets day that measured finasteride concentrations in semen [see Clinical Pharmacology (12.3)].
In an embryo-fetal development study, pregnant rats received finasteride during the period of major organogenesis (gestation days 6 to 17). At maternal doses of oral finasteride approximately 1 to 684 times the recommended human dose (RHD) of 1 mg/day (based on AUC at animal doses of 0.1 to 100 mg/kg/day) there was a dose-dependent increase in hypospadias that occurred in 3.6 to 100% of male offspring. Exposure multiples were estimated using data from nonpregnant rats. Days 16 to 17 of gestation is a critical period in male fetal rats for differentiation of the external genitalia. At oral maternal doses approximately 0.2 times the RHD (based on AUC at animal dose of 0.03 mg/kg/day), male offspring had decreased prostatic and seminal vesicular weights, delayed preputial separation and transient nipple development. Decreased anogenital distance occurred in male offspring of pregnant rats that received approximately 0.02 times the RHD (based on AUC at animal dose of 0.003 mg/kg/day). No abnormalities were observed in female offspring exposed to any dose of finasteride in utero.
No developmental abnormalities were observed in the offspring of untreated females mated with finasteride-treated male rats that received approximately 488 times the RHD (based on AUC at animal dose of 80 mg/kg/day). Slightly decreased fertility was observed in male offspring after administration of about 20 times the RHD (based on AUC at animal dose of 3 mg/kg/day) to female rats during late gestation and lactation. No effects on fertility were seen in female offspring under these conditions.
No evidence of male external genital malformations or other abnormalities were observed in rabbit fetuses exposed to finasteride during the period of major organogenesis (gestation days 6 to 18) at maternal doses up to 100 mg/kg/day (finasteride exposure levels were not measured in rabbits). However, this study may not have included the critical period for finasteride effects on development of male external genitalia in the rabbit.
The fetal effects of maternal finasteride exposure during the period of embryonic and fetal development were evaluated in the rhesus monkey (gestation days 20-100), in a species and development period more predictive of specific effects in humans than the studies in rats and rabbits. Intravenous administration of finasteride to pregnant monkeys at doses as high as 800 ng/day (estimated maximal blood concentration of 1.86 ng/mL or about 930 times the highest estimated exposure of pregnant women to finasteride from semen of men taking 1 mg/day) resulted in no abnormalities in male fetuses. In confirmation of the relevance of the rhesus model for human fetal development, oral administration of a dose of finasteride (2 mg/kg/day or approximately 120,000 times the highest estimated blood levels of finasteride from semen of men taking 1 mg/day) to pregnant monkeys resulted in external genital abnormalities in male fetuses. No other abnormalities were observed in male fetuses and no finasteride- related abnormalities were observed in female fetuses at any dose.
Finasteride tablets is not indicated for use in women.
It is not known whether finasteride is excreted in human milk.
Finasteride tablets is not indicated for use in pediatric patients.
Safety and effectiveness in pediatric patients have not been established.
Clinical efficacy studies with Finasteride tablets did not include subjects aged 65 and over. Based on the pharmacokinetics of finasteride 5 mg, no dosage adjustment is necessary in the elderly for finasteride tablets [see Clinical Pharmacology (12.3)]. However the efficacy of finasteride tablets in the elderly has not been established.
Caution should be exercised in the administration of finasteride tablets in those patients with liver function abnormalities, as finasteride is metabolized extensively in the liver [see Clinical Pharmacology (12.3)].
No dosage adjustment is necessary in patients with renal impairment [see Clinical Pharmacology (12.3)].
In clinical studies, single doses of finasteride up to 400 mg and multiple doses of finasteride up to 80 mg/day for three months did not result in adverse reactions. Until further experience is obtained, no specific treatment for an overdose with finasteride can be recommended.
Significant lethality was observed in male and female mice at single oral doses of 1500 mg/m2 (500 mg/kg) and in female and male rats at single oral doses of 2360 mg/m2 (400 mg/kg) and 5900 mg/m2 (1000 mg/kg), respectively.
Finasteride tablets contain finasteride as the active ingredient. Finasteride, a synthetic 4-azasteroid compound, is a specific inhibitor of steroid Type II 5α-reductase, an intracellular enzyme that converts the androgen testosterone into 5α-dihydrotestosterone (DHT).
The chemical name of finasteride is N-tert -Butyl-3-oxo-4-aza-5α-androst-1-ene-17β-carboxamide. The empirical formula of finasteride is C23 H36 N2 O2 and its molecular weight is 372.55. Its structural formula is:
Finasteride is a white crystalline powder with a melting point near 250°C. It is freely soluble in chloroform and in lower alcohol solvents but is practically insoluble in water.
Finasteride Tablets, USP are film-coated tablets for oral administration. Each tablet contains 1 mg of finasteride and the following inactive ingredients: lactose monohydrate, microcrystalline cellulose, pregelatinized starch, sodium starch glycolate, lauroylmacrogol 32 glycerides, magnesium stearate, Hypromellose, Titanium Dioxide, polyethylene glycol, Iron Oxide Red, and Iron Oxide Yellow.
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