Complete List of Finasteride Interactions with Medicines

Finasteride, known by the brand name Propecia, is a medicine used to treat hair loss in men. It is also used to treat Benign Prostate Hyperplasia (BPH) – an enlarged prostate. A condition that occurs mainly in men aged 50+. For treating hair loss, finasteride is used at a dose of 1 mg. For the treatment of BPH, the dose is 5 mg.

What is finasteride?

Finasteride is a medicine that inhibits the enzyme 5-α-reductase. This enzyme is involved in converting testosterone to dihydrotestosterone (DHT). By inhibiting this enzyme, finasteride blocks the conversion of testosterone to DHT. In other words, finasteride reduces the amount of DHT.¹

This is important because DHT is the leading cause of hair loss in men. DHT damages the hair follicles by disrupting the hair growth cycle, causing hair to shorten, fall out more quickly and more difficult to regrow. Finasteride works by reducing DHT production by 70%, which prevents further hair loss in about 80% of men.²

Finasteride interactions

Always keep your healthcare provider informed of any medications or supplements you take or plan to take while taking finasteride.

A total of 23 drugs are known to interact with finasteride, categorized as 0 major, 22 moderate, and 1 minor interactions.

Finasteride moderate drug interactions

abametapir topical, avacopan, diltiazem, duvelisib, fluconazole, fluvoxamine, fostamatinib, ginseng, itraconazole, larotrectinib, lonapegsomatropin, nefazodone, nelfinavir, saquinavir, selpercatinb, sirolimus, somapacitan-beco, somatrem, somatropin, tacrolimus, temsirolimus and voriconazole.

Finasteride minor drug interactions

Terazosin

Finasteride moderate disease interaction

liver disease and urinary obstruction.

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.

Major: Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.

Moderate: Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.

Minor: Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.

Alternatives to finasteride

If your healthcare provider advises that you shouldn't take finasteride, other alternatives are available for treating male pattern baldness (hair loss). They include:

Minoxidil

Minoxidil, known under the brand name Rogaine, is available as a lotion and a foam and in different strengths: 2% and 5%. Minoxidil can be bought at a pharmacy and is available without a prescription.

Minoxidil stimulates the hair growth cycle and extends the active growth phase (the period during which the hair grows). Minoxidil also improves the blood supply around the hair follicles, allowing them to absorb more nutrients. Combined, these effects result in an increase in hair growth, thickness and density.

Hair transplant

A hair transplant is a medical procedure in which the surgeon moves hair follicles from one place to another. The place where the surgeon takes the hair follicles is called the "donor area". Often the donor area consists of the back and sides of the head. The "recipient area" is where the hair follicles are moved to. Depending on how severe your hair loss is, this is often above the forehead and around the temples.

In a hair transplant, the surgeon fills in the bald spots with the hair he or she takes from the back of the head to create a new hairline. With a good surgeon, the results appear very natural.

Laser treatment

Low-level laser therapy (LLLT) is a treatment method that uses light. Red and infrared light to be precise; with a wavelength of 600 to 950 nanometers (0.0006 to 0.00095 mm).³ How this works exactly is not relevant for now, but let us say that light, depending on its wavelength, has positive or negative effects.

One of the effects attributed to the use of LLLT is that it promotes hair growth. This is shown in the study published in the scientific journal Skin Appendage Disorder.⁴ This study compared the effectiveness of the RAMACAP (LLLT device) with that of a fake device. They saw an increase of 10.21 cm² hairs in the laser group compared to an increase of 3.95 cm² hairs in the group treated with the fake device over a 6-month period.

Another study published in Lasers in Surgery and Medicine compared the effectiveness of the iGROW laser with Minoxidil 5%.⁵ They saw an increase of 49.60 cm² and 50.8 cm² hairs for Minoxidil and LLLT respectively after 4 months of treatment. Other studies also saw an increase in hair density after treatment with LLLT.⁶ ⁷ ⁸ The effect of LLLT is possibly due to the dilation of the blood vessels, known by the medical term vasolidation. A property shared with Minoxidil. Possibly both agents work on the same principle.

A note on the proposed alternatives

Although the treatments above are listed as alternatives to finasteride, it should be noted that they do not replace finasteride. Meaning: they don’t provide the same results finasteride does.

From these four treatments, finasteride is the only one that causes your DHT-levels te drop. It thereby fights the cause of hair loss and actively prevents your hair from falling out. Minoxidil, LLLT and a hair transplant do not. They have no impact whatsoever on your DHT-levels. Minoxidil and LLLT stimulate hair growth, while a hair transplant only tries to repair what has already been lost. They do not prevent further hair loss.