Proscar 5 mg Tablets

Brand Name

The medication is marketed under the brand name Proscar, a well-recognized label in the field of urological and hormonal therapy.

International Nonproprietary Name (INN)

The active pharmaceutical ingredient is identified globally as finasteride, a designation ensuring consistency across international medical and pharmacological standards.

Form of Release

Proscar is produced as film-coated tablets, intended for oral use. Each tablet contains 5 mg of the active substance and is typically packaged in blister packs or bottles, depending on regional distribution norms.

Composition

Each tablet of Proscar includes 5 mg of finasteride as its primary active component. The formulation incorporates several inactive ingredients, such as lactose monohydrate, which acts as a filler, and microcrystalline cellulose, providing structural support. Additional excipients like pregelatinized starch enhance disintegration, while magnesium stearate serves as a lubricant during manufacturing. The film coating consists of hypromellose, titanium dioxide, and FD&C Blue No. 2 aluminum lake, imparting a light blue color and protective layer. Trace amounts of other stabilizers may be included to maintain the drug’s integrity over time.

Pharmacologic Properties

Pharmacodynamics

Proscar exerts its therapeutic effect by selectively inhibiting the enzyme 5-alpha-reductase, specifically the type II isoform prevalent in prostate tissue. This enzyme converts testosterone into dihydrotestosterone (DHT), a potent androgen that drives prostate growth in conditions like benign prostatic hyperplasia (BPH). By blocking this conversion, the medication significantly reduces DHT levels in both the prostate and bloodstream, leading to a gradual decrease in prostate volume. This shrinkage relieves pressure on the urethra, improving urinary flow and alleviating symptoms such as weak stream, urgency, or nocturia.

The reduction in DHT also lowers prostate-specific antigen (PSA) levels by approximately 50% within six months, a change that impacts PSA-based screening for prostate cancer and requires adjusted clinical interpretation. Beyond symptom relief, the drug reduces the risk of acute urinary retention and the need for surgical intervention in men with enlarged prostates. Its specificity for type II 5-alpha-reductase distinguishes it from broader inhibitors, minimizing effects on other tissues like skin or hair, though some overlap with type I activity exists at higher doses. This targeted action underpins its efficacy in managing BPH over extended periods.

Pharmacokinetics

Following oral administration, Proscar is absorbed through the gastrointestinal tract, reaching peak plasma concentrations within 1 to 2 hours. Food intake does not substantially alter its bioavailability, allowing flexibility in dosing timing. The drug binds to plasma proteins at about 90%, distributing primarily to the bloodstream and prostate tissue, its key target.

Metabolism occurs predominantly in the liver, mediated by cytochrome P450 enzyme CYP3A4, which transforms finasteride into less active metabolites. The half-life averages 6 to 8 hours, though its pharmacological effects persist longer due to sustained DHT suppression in tissues. Elimination is split between urine (approximately 39% as metabolites) and feces (57%), with negligible amounts of unchanged drug excreted. The prolonged tissue impact means detectable effects may linger for weeks after discontinuation, necessitating specific precautions like blood donation restrictions.

Indications for Use

Proscar is primarily prescribed for the treatment of symptomatic benign prostatic hyperplasia in men with an enlarged prostate. This condition often leads to lower urinary tract symptoms, such as difficulty initiating urination or frequent nighttime awakenings, which the medication addresses by reducing gland size and improving flow. It is particularly beneficial for patients with moderate to severe symptoms seeking to avoid surgery.

The drug is also indicated to decrease the incidence of acute urinary retention and the need for invasive procedures like transurethral resection of the prostate (TURP) in men at risk. While not approved for prostate cancer prevention, its DHT-lowering effects have been explored in research settings, though such use remains off-label and requires careful medical oversight. Its role in long-term BPH management highlights its value in improving quality of life for affected individuals.

Contraindications

Proscar is contraindicated in women and children, as its mechanism targets male-specific androgen pathways and poses risks to fetal development. Pregnant women or those who may become pregnant should avoid handling crushed or broken tablets, as finasteride can be absorbed through the skin and may cause genital abnormalities in male fetuses.

Individuals with known hypersensitivity to finasteride or any tablet component, such as lactose, must not use this therapy, as reactions could range from mild irritation to severe allergic responses. Severe liver dysfunction is another barrier, given the drug’s hepatic metabolism, which could lead to unpredictable accumulation or toxicity. Patients with a history of significant adverse reactions to similar 5-alpha-reductase inhibitors are also excluded from treatment.

Method of Administration and Dosage

Administration Guidelines

The tablets should be taken orally, swallowed whole with water to ensure proper delivery to the stomach. They can be consumed with or without food, offering convenience in daily scheduling. Crushing or breaking the tablets is discouraged due to the risk of skin absorption and potential irritation to the mouth or throat.

Dosage for Adults and Children

For adult men with BPH, the recommended dose of Proscar is 5 mg once daily, equivalent to one tablet. This consistent regimen supports gradual prostate reduction and symptom relief over months. Children are not eligible for this treatment, as it is designed exclusively for adult males with prostate enlargement, and safety in pediatric populations has not been established.

Dose Adjustment in Specific Conditions

No dose modification is necessary for renal impairment, as kidney function has minimal impact on elimination. In mild to moderate liver dysfunction, the standard dose is typically tolerated, but severe hepatic impairment may require caution due to altered metabolism, though specific adjustments are not well-defined. Elderly patients generally follow the same dosing, with no routine changes unless comorbidities suggest otherwise. Regular monitoring ensures the regimen remains appropriate for individual health profiles.

Side Effects

Proscar may induce various side effects, though many patients experience only mild or temporary reactions. Common issues include sexual dysfunction, such as decreased libido, erectile difficulties, or reduced ejaculate volume, tied to its DHT-lowering effects. These symptoms often diminish with continued use but may persist in a small subset of users.

Breast changes, including tenderness or enlargement, are reported in some cases, typically resolving after discontinuation. Less frequently, patients experience dizziness or fatigue, possibly linked to hormonal shifts. Allergic reactions, such as rash or swelling, are rare but require immediate cessation if severe. Long-term use has raised questions about a potential association with high-grade prostate cancer, though evidence remains inconclusive, necessitating ongoing evaluation during therapy.

Overdose

Symptoms of Overdose

Excessive intake of Proscar is unlikely to produce acute, dramatic symptoms due to its slow-acting nature. Studies with doses up to 400 mg—far exceeding the therapeutic amount—showed no significant immediate toxicity, though prolonged excess might amplify side effects like sexual dysfunction or fatigue. Specific overdose symptoms are not well-documented, reflecting its gradual pharmacokinetic profile.

First Aid Measures

In the event of an overdose, medical consultation is recommended, though urgent intervention is rarely needed. No specific antidote exists, so management focuses on supportive care, such as monitoring vital signs and addressing any discomfort. The drug’s tissue persistence means effects may linger, but observation typically suffices unless complications arise.

Drug Interactions

Effects on Other Medications

Proscar has minimal impact on drugs metabolized by cytochrome P450 enzymes, including CYP3A4, as it is not a potent inhibitor or inducer. Co-administration with medications like warfarin or digoxin shows no significant pharmacokinetic interactions, supporting its safe use in patients with multiple therapies. Its primary effect is on DHT levels, which does not directly alter the metabolism of other drugs.

In rare cases, drugs that strongly inhibit CYP3A4, such as ketoconazole, might slightly increase finasteride levels, though this is seldom clinically meaningful. Patients should still report all medications to their healthcare provider to rule out unexpected interactions.

Compatibility with Alcohol and Food

Alcohol consumption does not affect the drug’s performance, allowing moderate use without concern for efficacy or safety. Food intake similarly has no notable impact on absorption, so the medication can be taken with meals or on an empty stomach, enhancing ease of use in daily routines.

Special Precautions

Use During Pregnancy and Breastfeeding

Proscar is contraindicated in women, particularly during pregnancy, due to risks of fetal harm. If absorbed by a pregnant woman, especially in the first trimester, it could disrupt male fetal genital development. Women who are or may become pregnant should avoid contact with broken tablets, and men taking the drug should refrain from blood donation for at least one month after discontinuation to prevent transfusion-related exposure. Breastfeeding considerations are irrelevant, as the therapy targets men exclusively.

Men using this medication should consider condom use if their partner is of childbearing age, as trace amounts may be present in semen, though the clinical significance of this is unclear.

Impact on Driving and Operating Machinery

The medication does not typically affect cognitive or motor skills, making it safe for most patients to drive or operate machinery. Rare reports of dizziness suggest initial caution until individual tolerance is confirmed, particularly in the early stages of treatment.

Considerations for Elderly and Pediatric Populations

Elderly men, a key demographic for BPH treatment, generally tolerate Proscar well, with no significant differences in response compared to younger adults. Age-related declines in liver function may warrant monitoring, though dose adjustments are rarely needed. Pediatric use is contraindicated, as the drug’s purpose and safety profile are irrelevant to children, and no data support its use in this group.