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Dutasteride (Avodart) Sexual Side Effects Can Be Daunting

Are men alerted to dutasteride (Avodart) sexual side effects? What about elevations in blood sugar, LDL cholesterol or liver enzymes. Does ED persist?

Avodart was approved by the FDA in 2001 to treat symptoms of an enlarged prostate gland. Dutasteride (the generic name) inhibits an enzyme called 5 alpha reductase (5AR). This reduces the conversion of testosterone to a metabolite called DHT (dihydrotestosterone).

Many people assumed that DHT was the bad actor that caused an enlarged prostate gland (aka BPH or benign prostate hypertrophy). DHT was also thought to contribute to male pattern baldness. Blocking it with 5ARIs (5 alpha reductase inhibitors) such as dutasteride or finasteride (Proscar) was supposed to facilitate urination and hair growth. People didn’t worry too much about dutasteride (Avodart) sexual side effects. That’s because they seemed pretty insignificant.

Dutasteride (Avodart) Sexual Side Effects:

If you look at the official prescribing information for Avodart you discover that the drug can cause impotence, decreased libido and “ejaculation disorders.” But when you compare dutasteride (Avodart) sexual side effects to placebo after about a year’s time, the drug doesn’t seem so bad:


Placebo 1.5%

Decreased Libido

Placebo 0.6%

Ejaculation disorders

Placebo 0.3%

Why should anyone get excited about such a seemingly small likelihood of adverse reactions? The difference between dutasteride (Avodart) sexual side effects and placebo is apparently minuscule, if you believe the drug company clinical trial data. If anything, it appears that people taking the placebo had a greater risk of impotence than those on dutasteride (by 0.1%).

That difference is unlikely to be statistically significant. In fact a 0.1 – 0.2% difference is so minuscule that many health professionals probably assume it means that the drug isn’t likely to interfere with human sexuality. Why warn a man about erectile dysfunction, decreased libido, ejaculation disorders or breast enlargement if the clinical trials apparently produced such low-level complications?

Evidence to the Contrary:

We have heard from many men who have discovered, to their chagrin, that drugs like dutasteride and finasteride do indeed have sexual side effects. A study in the journal Andrology (April 28, 2017) notes:

“In conclusion, present data show that the use of 5ARI [5 alpha reductase inhibitor] significantly increases the risk of erectile dysfunction and hypoactive sexual desire in subjects with benign prostatic hyperplasia. Patients should be adequately informed before 5ARIs are prescribed.”

A reader offers this question:

Q. I started taking Avodart a few months ago for an enlarged prostate. After only a few days, I thought, this is great. I can sleep all night without getting up to use the bathroom. I didn’t notice any side effects.

After about six weeks, I found I had no sex drive at all, not even sexual attraction to my wife. I stopped taking Avodart and a few weeks later my sex life was back.

I’ve gone back to saw palmetto. I would rather get up twice a night and still have a sex life.

A. Dutasteride (Avodart) sexual side effects include both erectile dysfunction and low libido (PeerJ, online, March 9, 2017).  In some cases, sexual dysfunction may persist long after the medication has been discontinued (Journal of Sexual Medicine, March 2011).

We suspect that many prescribers may not realize that the FDA includes the statement that adverse sexual reactions “may persist after treatment discontinuation.”

According to the authors of an article about “Persistent Erectile Dysfunction,” the risk for this problem is greater the longer the men take drugs like dutasteride or finasteride:

“Of 103 young men with new ED [erectile dysfunction], 34 (33%) had new PED [persistent erectile dysfunction. Young men with >205 [greater than 205] days of finasteride exposure had 4.9 fold higher risk of PED than men with shorter exposure.”

They note that more than two million men could be exposed to such drugs.

Their conclusion:

“We expect that our finding of an association between debilitating sexual dysfunction and exposure to finasteride or dutasteride will be of particular interest to prescribers and patients considering medical management of androgenic alopecia or symptomatic treatment of prostatic hyperplasia.”

Readers Who Are Mad as Hell:

Eric in Connecticut is furious:

“I’m bothered to no end by these reports of sexual side effects that weren’t mentioned when the drug was first prescribed. I had this same experience too. At this point I’m just furious!

“I was prescribed Flomax a few years ago as an aid to my BHP [benign prostate hypertrophy]. I was subsequently prescribed Avodart as an adjunct treatment. Never once was the mention of sexual side effects ever broached.

“I’m angry as hell right now. Don’t these professional people understand that their patients have more needs then those that are just physical ones?”

Ken in Colorado has a similar complaint:

“Taking tamsulosin and finasteride has reduced night-time urination but also has totally killed my sex life.

“The penis remains flaccid throughout the whole time. It is extremely demoralizing. I, too, was not informed of this possibility by my doctor. I would like to have considered another option – perhaps a surgical reduction of the prostate instead of via these nasty medications.”

Nigel in New York adds:

“I had been taking Avodart for many years and developed inability to orgasm during sex. When I did ejaculate, less semen was discharged. I discontinued Avodart a month ago and so far no improvement…”

Other Unexpected Dutasteride Side Effects:

When the drugs dutasteride and finasteride were approved by the FDA there was little concern about other complications. A recent article in the journal Hormone Molecular Biology and Clinical Investigation (online, June 21, 2017) reveals some additional unexpected and unwelcome adverse reactions.

In this analysis the investigators note that a drug like dutasteride that inhibits 5 alpha reductase “alters metabolic function resulting in undesirable metabolic and sexual adverse side effects.” They report that long-term dutasteride treatment resulted in increases in blood glucose, HbA1C (a longer-term assessment of blood sugar levels), total cholesterol, LDL cholesterol and liver enzymes. Testosterone levels were reduced and Aging Male Symptom (AMS) scores went up.


“Our findings suggest that long-term dutasteride therapy produces worsening of ED, reduced T levels and increased glucose, HbA1c and alters lipid profiles, suggesting induced imbalance in metabolic function. We strongly recommend that physicians discuss with their patients these potential serious adverse effects of long-term dutasteride therapy prior to instituting this form of treatment.”

The Bottom Line on Dutasteride (Avodart) Sexual Side Effects:

To read more reader reports on these adverse drug reactions here are a few links:

Long-Lasting Sexual Side Effects from Prostate Pill

Will Drugs for Benign Prostate Hyperplasia (BPH) Ruin Your Sex Life?

Sex No Longer Pleasurable

Drug for Prostate Made Penis Shrink

Share your own story about  dutasteride (Avodart) sexual side effects below in the comment section. If you have had a good experience with this drug or with finasteride, please share that perspective as well.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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