Finasteride Side Effects

Many of the side effects of finasteride concern all men who are beginning the battle against hair loss. If you’ve heard of this medication from a friend, a work colleague, or even while doing your research on the internet, you probably know that finasteride has become widely used due to excellent results in the treatment of male pattern baldness. But do you know what finasteride does to your body? Are you familiar with the side effects? And not only the most common ones, but also those that might stay after using finasteride for a long time.

Finasteride is an antiandrogen agent frequently prescribed to treat benign prostatic hyperplasia (BPH) and male pattern baldness (MPB). An antiandrogen is any drug that blocks the effects of male hormones on the male body. In this case, finasteride is a medication that works by inhibiting 5-alpha reductase type 2 enzyme which prevents the conversion of testosterone to its more active form, dihydrotestosterone (DHT), and hence decreasing the levels of this hair follicle killing hormone. This FDA-approved medication is available on prescription only and can be found in drugstores as the brand names Proscar or Propecia, and also in a generic version.

What are side effects of finasteride?

As you should know, every drug that we use can cause an unwanted response when taken in normal doses, and finasteride is no exception. Some may experience mild or severe, temporary or permanent side effects. The side effects observed with finasteride are therefore related to its antiandrogen effects and since male pattern baldness requires prolonged and continuous use of the drug, the risk of side effects is high.

Common side effects of finasteride Uncommon side effects of finasteride
More than 1 in 100 men get the following finasteride adverse effects which usually appear shortly after starting the treatment. The side effects listed below are not experienced by all men taking this medication (less than 1 in 100 men).
  • Trouble getting or keeping an erection (impotence/erectile dysfunction)
  • Low sperm count
  • Ejaculation disorder
  • Testicular pain
  • Decreased volume of ejaculate
  • Skin reactions
  • Muscle weakness
  • Low blood pressure
  • Fluid retention (legs, feet, arms or hands)
  • Dizziness or faintness
  • Unusual heartbeat
  • Rapid weight gain
  • Depression

How long do side effects last?

Many of these side effects are manageable and some may disappear on their own over time once your body adjusts to the medicine. However, you should get emergency medical care if you have signs of an allergic reaction such as skin rash, difficulty breathing, swelling of your face, lips, tongue, or throat.

Although breast cancer in men is a rare side effect, this should not be taken lightly and any men experiencing some kind of breast changes should see a specialist.


Post-finasteride syndrome (PFS)

The post-finasteride syndrome (PFS) is a condition that occurs in patients with MPB or BPH after discontinuation of 5-alpha reductase inhibitors such as finasteride. This syndrome can lead to a wide variety of persistent sexual, neurological and physical adverse effects, which may last months or even years. While symptoms vary from person to person, the PFS can have a great impact on men’s life.

There are currently no known factors that can predict which patients will suffer from this syndrome, however it has been suggested that a patient's history of preexisting mental health disorder can put men at an increased risk. Unfortunately, post-finasteride syndrome is not recognized by the medical community yet and studies have not been conclusive enough to explain with certainty why this syndrome is triggered.

If you are concerned about finasteride side effects, discuss the risks and benefits of this drug with your doctor. A healthcare professional is the only one who can advise you on what to do if any of the mentioned side effects occur.

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