Propecia

General information

Propecia is a drug used for the treatment of androgenetic alopecia in men. The drug helps to slow down hair loss and stimulates hair growth by acting on the hormonal mechanisms associated with baldness.

Trade name

Propecia

International Nonproprietary Name (INN)

Finasteride

Form of release

The drug is available in the following form:

• Finasteride film-coated tablets: 1 mg

Composition

Acting substance

Finasteride.

Auxiliary components

The composition includes the following additional substances:

• Lactose monohydrate, microcrystalline cellulose, pregelatinized starch, sodium starch glycolate, magnesium stearate, hypromellose (shell), titanium dioxide, iron oxide yellow, iron oxide red.

Pharmacologic properties

Pharmacodynamics

Propecia exerts its therapeutic action by inhibiting the enzyme 5-alpha reductase type 2, which converts testosterone to dihydrotestosterone (DHT). Elevated levels of DHT are a key factor in the development of androgenetic alopecia, as it causes miniaturization of hair follicles; finasteride reduces the concentration of DHT in the scalp and blood, which slows hair loss and promotes hair regrowth. The drug does not affect androgen receptors and does not have estrogenic, anti-estrogenic or progestagenic properties.

The effect of using Propecia becomes apparent after 3-6 months of regular use: the number of hair in the growth phase (anagen) increases, and follicles move from the resting to active stage. The maximum result is achieved after 1-2 years, after which maintenance therapy prevents the resurgence of baldness. The drug is intended exclusively for men and is not effective in other types of alopecia, not related to hormonal causes.

Pharmacokinetics

Finasteride is well absorbed from the gastrointestinal tract after oral administration, reaching maximum plasma concentrations after 1-2 hours. Bioavailability is about 63% and does not depend on food intake. The drug penetrates the blood-brain barrier in minimal amounts, which reduces the effect on the central nervous system.

Binding to plasma proteins reaches 90%, and the volume of distribution is about 76 liters, indicating uniform distribution in tissues, including the scalp. Metabolism occurs in the liver with the participation of enzymes of the cytochrome P450 (CYP3A4) system, where finasteride is converted into two active metabolites with lower activity (about 20% of the original substance). The elimination half-life varies from 4.7 to 7.1 hours, but the pharmacologic effect persists longer due to enzyme inhibition.

Extraction is mainly through the intestine with bile (about 57% as metabolites) and partially through the kidneys (39%). In elderly patients the elimination half-life may increase up to 8 hours, but this does not require dose adjustment. In case of hepatic or renal dysfunction, metabolism and excretion may be slowed down, which is taken into account during long-term use.

Indications for use

Diseases and conditions for which the drug is prescribed

Propecia is prescribed for the following conditions:

• Androgenetic alopecia in men (male pattern baldness, stage II-V on the Norwood scale), to slow hair loss and stimulate hair growth.

Contraindications

Conditions under which the use of the drug is prohibited

The use of Propecia is prohibited in the following conditions:

• Hypersensitivity to finasteride or any auxiliary components of the drug.
• Female gender (the drug is not intended for women, especially in pregnancy due to the risk of teratogenic effects on the male fetus).
• Childhood (under 18 years of age), as safety and efficacy have not been established.
• Severe hepatic insufficiency affecting the drug metabolism.

How to use and dosage

How to take

Propecia is taken orally, regardless of meals. Tablets should be swallowed whole, without chewing or breaking, drinking enough water (100-150 ml). To achieve a stable effect, it is recommended to take the drug at the same time of day.

Dosages for adults and children

Adults

Standard dosage for men:

• 1 mg (1 tablet) once daily.

The treatment course is long, usually at least 3-6 months for first visible results and 1-2 years for maximum effect. Discontinuation of use results in a gradual return of hair loss over a period of 6-12 months.

Children

Propecia is not used in children and adolescents under 18 years of age, as the drug is intended exclusively for the treatment of androgenetic alopecia in adult males, and safety in children has not been studied.

Dose correction for certain conditions

Dose adjustment is not required in renal insufficiency, as excretion through the kidneys is less than 40% and does not significantly affect pharmacokinetics. In moderate hepatic insufficiency the dosage remains standard, but in severe hepatic insufficiency (Child-Pugh class C) the drug is contraindicated because of the risk of accumulation due to slow metabolism. In elderly patients (over 65 years of age) the dose is not adjusted, but liver monitoring is required.

Side effects

Possible adverse reactions of the body

The following adverse reactions may occur during the use of Propecia:

• From the side of the reproductive system: decreased libido, erectile dysfunction, decreased ejaculate volume (usually reversible after withdrawal).
• Side of the endocrine system: soreness or enlargement of the breast glands (gynecomastia).
• Skin: rash, itching, rarely - alopecia of another type.
• Nervous system: depression, anxiety, decreased mood.
• Allergic reactions: urticaria, swelling of the lips or face (in rare cases).
• Other: testicular pain, fatigue, increased levels of liver enzymes.

Overdose

Symptoms of overdose

The following symptoms may occur if the recommended dose of Propecia is exceeded:

• Exacerbation of side effects: marked decrease in libido, dizziness, weakness.
• Hormonal disorders: temporary increase in the sensitivity of the mammary glands.
• Gastrointestinal disorders: nausea, abdominal discomfort (in rare cases).

First aid measures

In case of suspected overdose it is necessary:

1. Stop taking the drug.
2. Seek medical attention to assess the condition.
3. Rinse stomach if ingestion has occurred recently (within 1-2 hours).
4. Give activated charcoal (1 g/kg body weight) to reduce absorption.
5. Provide symptomatic support: monitor the patient's condition until normalization.

Interaction with other drugs

Effects on the effects of other drugs

Propecia has limited interactions with other medicines:

• No significant effect on drugs metabolized by the cytochrome P450 system, such as warfarin, theophylline or digoxin.
• Combined use with CYP3A4 inhibitors (e.g., ketoconazole) may slightly increase the concentration of finasteride in the blood, but this does not require dose adjustment.
• CYP3A4 inducers (e.g., rifampicin) may decrease finasteride levels, potentially reducing its efficacy.
• No interaction with androgenic drugs or hormonal contraceptives, as it does not affect androgen receptors.

Compatibility with alcohol and food

Alcohol consumption during Propecia treatment does not directly affect the effectiveness of the drug, but excessive alcohol consumption may increase side effects such as depression or fatigue. Food intake does not affect the absorption of finasteride, so the drug can be taken both before and after meals without altering its pharmacokinetics.

Special Instructions

Use in pregnancy and breastfeeding

Propecia is contraindicated in women, especially during pregnancy, because of the risk of teratogenic effects on the male fetus: finasteride may impair the development of the genital organs in the embryo. Pregnant women are not even allowed to touch crushed or damaged tablets, as the drug can be absorbed through the skin. During breastfeeding the use is also inadmissible, as the data on the penetration of finasteride into breast milk are insufficient.

Effects on driving and driving mechanisms

Propecia has no direct effect on the central nervous system and does not cause drowsiness or impaired coordination. However, some patients may experience side effects, such as fatigue or depression, which may indirectly affect the ability to drive vehicles or machinery; in such cases, it is recommended to assess individual reaction before performing such tasks.

Particulars of use in the elderly and children

In elderly men (over 65 years) Propecia is used in a standard dose of 1 mg per day, but the effectiveness may be lower due to age-related changes in the hormonal background; monitoring of liver function is required. The drug is not intended for children and adolescents under 18 years of age, as androgenetic alopecia is not characteristic of this age group, and the effect on the development of the endocrine system has not been studied.