Does tadalafil lower PSA levels? This is a common question for men taking this medication for erectile dysfunction or benign prostatic hyperplasia who are also monitoring their prostate health. Prostate-specific antigen (PSA) testing is an important tool in assessing prostate conditions, and understanding how medications may influence results is essential for accurate interpretation. Unlike some prostate medications, tadalafil—a phosphodiesterase type 5 (PDE5) inhibitor—does not significantly affect PSA levels. This article examines the evidence, explains how tadalafil works, and clarifies which medications do alter PSA results, helping you make informed decisions about prostate health monitoring.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medication primarily used to treat erectile dysfunction (ED) and the urinary symptoms associated with benign prostatic hyperplasia (BPH). It belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, which also includes sildenafil and vardenafil.

The mechanism of action involves inhibiting the PDE5 enzyme, which is found in smooth muscle cells lining blood vessels. By blocking this enzyme, tadalafil increases levels of cyclic guanosine monophosphate (cGMP), a chemical messenger that promotes smooth muscle relaxation and vasodilation. In the context of erectile dysfunction, this enhanced blood flow to the penis facilitates achieving and maintaining an erection when sexually stimulated.

For men with BPH, tadalafil helps relax smooth muscle in the prostate and bladder, improving urinary flow and reducing symptoms such as difficulty starting urination, weak stream, and frequent nighttime urination. Tadalafil is available in two dosing regimens: on-demand (taken as needed before sexual activity) or once-daily at lower doses for both ED and BPH symptoms.

Tadalafil has a longer duration of action compared to other PDE5 inhibitors, with effects lasting up to 36 hours. Common side effects include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion. These are generally mild and transient.

Important safety considerations include contraindications with nitrate medications (used for angina) and guanylate cyclase stimulators such as riociguat. Caution is advised in men with certain cardiovascular conditions. Tadalafil is licensed by the MHRA and available on NHS prescription for specific indications, though NHS prescribing for ED is restricted to certain medical conditions. If you experience side effects, report them via the MHRA Yellow Card scheme.

Understanding PSA Tests and What They Measure

Prostate-specific antigen (PSA) is a protein produced by cells in the prostate gland, both normal and cancerous. A PSA test measures the level of this protein in the blood and is commonly used as part of prostate health assessment, particularly in men over 50 or those with urinary symptoms.

PSA levels are measured in nanograms per millilitre (ng/mL) of blood. In the UK, PSA results are typically interpreted using age-specific reference ranges, as PSA naturally increases with age. Laboratory reference ranges may vary, but general age-specific thresholds used in the NHS Prostate Cancer Risk Management Programme are:

• Age 50-59: up to 3.0 ng/mL

• Age 60-69: up to 4.0 ng/mL

• Age 70 and over: up to 5.0 ng/mL

It is crucial to understand that elevated PSA is not specific to prostate cancer. Numerous benign conditions can raise PSA levels, including:

• Benign prostatic hyperplasia (BPH) – non-cancerous prostate enlargement

• Prostatitis – inflammation or infection of the prostate

• Urinary tract infections

• Recent ejaculation (within 48 hours)

• Vigorous exercise, particularly cycling

• Prostate instrumentation (biopsy, cystoscopy)

• Urinary catheterisation

Before having a PSA test, you should avoid ejaculation and vigorous exercise for 48 hours. If you've had a urinary tract infection, prostate instrumentation or biopsy, it's advisable to wait 6 weeks before testing.

The NHS does not currently offer a national PSA screening programme, as evidence suggests the benefits do not clearly outweigh the risks of overdiagnosis and overtreatment. However, the Prostate Cancer Risk Management Programme allows informed men aged 50 and over to request a PSA test after discussing the implications with their GP.

Medications That Can Affect PSA Results

Several medications can influence PSA levels, and understanding these interactions is essential for accurate test interpretation. 5-alpha reductase inhibitors (5-ARIs), such as finasteride and dutasteride, are the most significant PSA-lowering medications. These drugs, used to treat BPH and male pattern baldness, work by blocking the conversion of testosterone to dihydrotestosterone (DHT), which shrinks the prostate over time. 5-ARIs typically reduce PSA levels by approximately 50% after six months of treatment. Clinicians account for this by doubling the measured PSA value in men taking these medications, as recommended in UK clinical guidance.

Regarding tadalafil specifically, there is no evidence that it significantly lowers PSA levels. According to the MHRA-approved product information, clinical trials and post-marketing surveillance have not demonstrated a consistent PSA-reducing effect from PDE5 inhibitors like tadalafil. Unlike 5-ARIs, tadalafil does not alter prostate size or hormonal pathways that would be expected to affect PSA production. The medication's mechanism—smooth muscle relaxation through PDE5 inhibition—does not directly influence the cellular processes responsible for PSA secretion.

Other medications have been studied for potential effects on PSA, but the evidence is limited and inconsistent:

• Antibiotics – may temporarily lower PSA if treating bacterial prostatitis, but should only be used when infection is confirmed, not to manipulate PSA results

• Non-steroidal anti-inflammatory drugs (NSAIDs) – some observational studies suggest modest PSA reduction with long-term use, but clinicians do not routinely adjust PSA interpretation for NSAID use

• Statins – some evidence indicates possible slight PSA lowering, but this is not considered clinically significant for test interpretation

• Thiazide diuretics – limited evidence of association with lower PSA levels

If you are taking any regular medications, it is important to inform your GP before PSA testing, as this information helps with accurate result interpretation and clinical decision-making.

When to Discuss PSA Testing With Your GP

PSA testing should be an informed decision made in consultation with your GP, weighing potential benefits against risks of false positives, anxiety, and unnecessary interventions. You should consider discussing PSA testing if you:

• Are aged 50 or over with concerns about prostate health

• Have a family history of prostate cancer (father or brother diagnosed, especially before age 60)

• Are a Black man (of African or Caribbean heritage), which carries higher prostate cancer risk

• Experience lower urinary tract symptoms such as difficulty urinating, weak stream, frequent urination (especially at night), or urgency

• Have been advised to have testing due to an abnormal digital rectal examination

Men at higher risk, particularly Black men or those with strong family history, may wish to discuss testing from around age 45.

Before testing, your GP should explain that PSA tests are not definitive for cancer diagnosis and that elevated results often lead to further investigations, including MRI scans and possibly prostate biopsies, which carry their own risks. Conversely, some prostate cancers do not significantly raise PSA levels, meaning a normal result does not completely exclude cancer.

When to seek urgent medical advice:

• Visible blood in urine (haematuria)

• Acute urinary retention (sudden inability to pass urine)

• Unexplained weight loss with urinary symptoms

• New, severe bone pain, particularly in the back, hips, or pelvis, especially if accompanied by other symptoms

If you are taking tadalafil for BPH or ED, inform your GP, though this should not significantly affect your PSA results. According to NICE guidance, men with lower urinary tract symptoms should be assessed holistically (CG97), with PSA testing forming part of a broader clinical evaluation. If your PSA is elevated, your GP will consider referral based on age-specific thresholds (NICE NG12) and may arrange repeat testing or further investigations such as MRI before any biopsy (NICE NG131). Your GP can help determine the most appropriate timing and interpretation of PSA testing based on your individual circumstances and medication history.

Frequently Asked Questions