Medications That Affect Erections: What the Evidence Shows and What to Ask Your Doctor

Several classes of prescription medication are associated with reduced erectile function. Which ones, and by how much, is less clear-cut than most drug labels suggest. Some drugs widely believed to cause erectile dysfunction perform no differently from placebo in controlled trials, and in several studies a large share of the reported effect tracks what the patient was told to expect rather than the drug itself.

Do not stop or change a prescription because of this article. Stopping a blood pressure or cardiac medication carries risks considerably greater than erectile dysfunction. Everything below is intended to help you raise the subject with the doctor who prescribed it.

Drug classes associated with erectile dysfunction

The classes most consistently linked to erectile or sexual dysfunction are:

• Thiazide and thiazide-like diuretics — for example chlorthalidone and hydrochlorothiazide
• Beta blockers — for example metoprolol, atenolol, propranolol
• 5-alpha reductase inhibitors — finasteride and dutasteride, prescribed for benign prostatic hyperplasia and hair loss
• Antidepressants, particularly selective serotonin reuptake inhibitors
• Anti-androgen therapy used in prostate cancer treatment

Classes with neutral or favorable effects on erectile function include ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers such as diltiazem and amlodipine.

What controlled trials show about blood pressure medication

The clearest evidence comes from the Treatment of Mild Hypertension Study (TOMHS), a randomized, double-blind trial of 902 people, including 557 men, comparing placebo against five antihypertensive drugs over four years.

At 24 months, 17.1% of men taking the diuretic chlorthalidone reported erection problems, against 8.1% of men taking placebo. That is a real and meaningful difference.

The other four drugs behaved differently. The beta blocker (acebutolol), the ACE inhibitor (enalapril) and the calcium channel blocker (amlodipine) all produced erection problem rates similar to placebo. In a trial designed to detect exactly this, three of the four active drugs were indistinguishable from no treatment.

This matters for anyone who has been told that blood pressure medication causes erectile dysfunction as a general rule. On the trial evidence, the association is strongest for thiazide diuretics, weaker and less consistent for beta blockers, and largely absent for the other common classes.

Beta blockers specifically

Beta blockers remain the class most often blamed. Older non-selective agents have a stronger association than newer selective ones, and nebivolol has been studied as a possible exception because of its effect on nitric oxide. But the size of the effect in blinded trials is consistently smaller than the size of the effect in everyday reporting — which brings up the next point.

Expectation affects how often side effects are reported

Two blinded studies have measured this directly.

In a study of 96 men with newly diagnosed cardiovascular disease and no existing erectile dysfunction, all participants were given the same drug — atenolol 50 mg daily — but told different things about it. Men who were not told what they were taking reported erectile dysfunction at 90 days at a rate of 3%. Men told they were taking a beta blocker reported 15%. Men told it was a beta blocker and that it might cause erectile dysfunction reported 31%. In the second phase, men who had developed erectile dysfunction were given either sildenafil or placebo, and the two produced no significant difference in recovery.

A separate trial of finasteride found the same pattern. Of 107 men taking finasteride 5 mg, those counseled about possible sexual side effects reported sexual dysfunction at 43.6%, against 15.3% among those not counseled. For erectile dysfunction specifically the figures were 30.9% and 9.6%.

Neither study shows that these drugs are free of sexual side effects. Finasteride does have a measurable effect: in the four-year PLESS trial of 3,040 men with benign prostatic hyperplasia, sexual adverse events occurred in 15% of men taking finasteride 5 mg against 7% taking placebo. What the studies show is that a substantial part of what gets reported in ordinary practice is driven by expectation, and that this component responds to placebo.

The practical consequence is that starting a drug and noticing a change does not establish that the drug caused it.

Separating medication effects from age-related change

Most men who ask this question are taking a new medication and are also several years older than the last time they thought about the subject. Both can be true at once, and the pattern of the difficulty is more informative than its timing.

Some observations that help distinguish them:

• Onset. A drug effect usually appears within days to a few weeks of starting or increasing a dose. Age-related vascular change develops over years.
• Reversal. A drug effect typically improves within weeks of stopping or switching, under medical supervision. Age-related change does not reverse on its own.
• Libido versus mechanics. Reduced desire points more toward a hormonal or central effect, which is characteristic of anti-androgens, 5-alpha reductase inhibitors and some antidepressants. Unchanged desire with reduced firmness points more toward a vascular cause.
• Pattern of failure. Difficulty achieving an erection suggests a problem with blood entering the penis. An erection that starts adequately and then fades, or that fails on changing position, suggests blood is leaving too quickly. That second pattern is characteristic of venous leak and is not a typical medication effect.
• Morning erections. Their persistence suggests the underlying mechanism is still functioning, which shifts attention toward drug effects, psychological factors, or early vascular change rather than established structural disease.

Erectile dysfunction as a cardiovascular signal

There is a reason this question deserves care rather than a quick medication switch. The 2018 American Urological Association Erectile Dysfunction Guideline states as a Clinical Principle that men should be counseled that erectile dysfunction is a risk marker for underlying cardiovascular disease and other conditions warranting evaluation.

The penile arteries are narrow, and systemic vascular disease frequently shows there before it shows elsewhere. A man taking blood pressure medication already has a diagnosed vascular condition. Attributing a new erectile problem to his tablets, and stopping there, can mean missing the progression of the disease the tablets were prescribed for. Our article on what the AUA Guideline says about venous leak covers the guideline's approach in more detail.

What to do

• Keep taking your medication until the prescribing doctor advises otherwise.
• Record the timing. Note when the medication started or changed and when the erectile difficulty began. A gap of days to weeks is informative; a gap of years is less so.
• Describe the pattern, not just the problem. Whether desire has changed, whether you can achieve an erection but not keep it, whether morning erections continue. Our guide on how to talk to your doctor about erectile dysfunction sets out what to bring to the appointment.
• Ask whether an alternative within the same class exists. Where a thiazide diuretic is implicated, other classes control blood pressure with less associated effect. This is a decision for the prescribing doctor, who is weighing your cardiovascular risk as well.
• Ask for a vascular assessment if the difficulty persists after any medication question is settled.

Many men find this difficult to raise, particularly with a cardiologist rather than a urologist. It is a legitimate clinical question, and a prescriber cannot weigh a side effect that has not been mentioned.

References

• Grimm RH Jr, Grandits GA, Prineas RJ, et al. Long-term effects on sexual function of five antihypertensive drugs and nutritional hygienic treatment in hypertensive men and women. Treatment of Mild Hypertension Study (TOMHS). Hypertension. 1997;29(1):8–14. https://www.ahajournals.org/doi/10.1161/01.HYP.29.1.8
• Silvestri A, Galetta P, Cerquetani E, et al. Report of erectile dysfunction after therapy with beta-blockers is related to patient knowledge of side effects and is reversed by placebo. European Heart Journal. 2003;24(21):1928–1932. https://academic.oup.com/eurheartj/article-abstract/24/21/1928/450074
• Mondaini N, Gontero P, Giubilei G, et al. Finasteride 5 mg and sexual side effects: how many of these are related to a nocebo phenomenon? Journal of Sexual Medicine. 2007;4(6):1708–1712. https://pubmed.ncbi.nlm.nih.gov/17655657/
• Nickel JC, Fradet Y, Boake RC, et al. Proscar Long-term Efficacy and Safety Study (PLESS): efficacy and safety of finasteride 5 mg in 3,040 men with benign prostatic hyperplasia over four years.
• Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. Journal of Urology. 2018;200(3):633–641. AUA Guidelines page