Tadalafil is a widely prescribed phosphodiesterase type 5 (PDE5) inhibitor used to treat erectile dysfunction and benign prostatic hyperplasia in the UK. Whilst generally well tolerated, post-marketing surveillance has documented rare reports of hearing-related adverse effects, including tinnitus—a persistent ringing or buzzing in the ears. Although no definitive causal link has been established, regulatory authorities include these events in product information. Understanding the potential association, recognising symptoms early, and knowing when to seek medical advice are essential for safe use of this medication.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medication primarily used to treat erectile dysfunction (ED) and the symptoms of benign prostatic hyperplasia (BPH). It belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. In the UK, tadalafil is available under brand names such as Cialis, as well as generic formulations with marketing authorisation.

The mechanism of action centres on the inhibition of the PDE5 enzyme, which is found in the smooth muscle cells lining blood vessels. During sexual stimulation, nitric oxide is released in the erectile tissue of the penis, which activates an enzyme that produces cyclic guanosine monophosphate (cGMP). This chemical messenger relaxes smooth muscle and increases blood flow to the penis, facilitating an erection. PDE5 normally breaks down cGMP, so by inhibiting this enzyme, tadalafil helps maintain higher levels of cGMP, thereby prolonging vasodilation and improving erectile function.

Tadalafil is also licensed for the treatment of pulmonary arterial hypertension under the brand name Adcirca, where its vasodilatory effects help reduce blood pressure in the lungs. This use is specialist-initiated and has different dosing requirements. The drug is notable for its long duration of action—up to 36 hours—which distinguishes it from other PDE5 inhibitors like sildenafil. This extended half-life allows for greater spontaneity in sexual activity.

Dosing varies depending on the indication: for ED, tadalafil may be taken on demand (typically 10 mg or 20 mg) or as a daily low-dose regimen (2.5 mg or 5 mg). For BPH, a daily 5 mg dose is commonly prescribed. Tadalafil should not be taken more than once per day. NICE Clinical Knowledge Summary on erectile dysfunction supports the use of PDE5 inhibitors as a first-line pharmacological treatment following appropriate assessment and counselling. Tadalafil is not indicated for women or those under 18 years of age.

Why Might Tadalafil Affect Hearing?

While tadalafil is generally well tolerated, there have been post-marketing reports of hearing-related adverse effects. According to the Summary of Product Characteristics (SmPC), sudden decrease or loss of hearing has been reported in temporal association with tadalafil, sometimes accompanied by tinnitus (ringing or buzzing in the ears) and dizziness. The frequency of these events is listed as 'not known' as it cannot be estimated from the available data.

It is important to note that there is no definitive causal link established between tadalafil and tinnitus, but the association has been documented in pharmacovigilance data and included in product information approved by regulatory authorities.

The potential mechanisms behind these effects are hypothetical. One theory involves the non-selective inhibition of phosphodiesterase enzymes beyond PDE5. Tadalafil also has some activity against PDE11, and to a lesser extent other PDE isoforms, which are expressed in various tissues including the cochlea (inner ear). The cochlea relies on precise regulation of blood flow and ionic balance for normal auditory function. Alterations in cochlear blood flow or cellular signalling due to PDE inhibition could theoretically disrupt hearing mechanisms.

Another hypothesis relates to vascular effects. Tadalafil's vasodilatory action may alter blood flow dynamics in the small vessels supplying the inner ear, potentially affecting auditory function, though the exact pathophysiology remains unclear.

It is also worth noting that tinnitus is a relatively common symptom in the general population, particularly among older adults who are also the primary users of tadalafil for ED or BPH. This makes it challenging to distinguish drug-related tinnitus from coincidental or age-related auditory changes.

What to Do If You Experience Tinnitus While Taking Tadalafil

If you develop a sudden decrease or loss of hearing while taking tadalafil, you should stop taking the medication immediately and seek urgent medical advice, as advised in the SmPC. If you experience new tinnitus without hearing loss, you should seek urgent medical advice and withhold further doses until you have been reviewed by a healthcare professional.

Contact your GP or call NHS 111 as soon as possible if you notice:

• Persistent ringing, buzzing, or hissing sounds in one or both ears

• Sudden reduction in hearing ability

• A sensation of fullness or pressure in the ear

• Dizziness or vertigo accompanying the auditory symptoms

Your healthcare provider will take a detailed history, including the timing of symptom onset in relation to tadalafil use, any other medications you are taking, and relevant medical history such as previous ear problems or cardiovascular disease. A physical examination of the ears and possibly an audiometric assessment (hearing test) may be arranged to evaluate the extent of any hearing impairment.

In some cases, referral to an ear, nose, and throat (ENT) specialist may be necessary, particularly if hearing loss is significant. NICE guidance on sudden sensorineural hearing loss recommends urgent specialist assessment, ideally within 24 hours, as some causes may benefit from early treatment with corticosteroids.

It is essential not to restart tadalafil without discussing the situation with your doctor. Alternative treatments for erectile dysfunction or BPH may be considered, depending on your individual circumstances. If tadalafil is deemed the likely cause, your healthcare provider may report the adverse event to the MHRA's Yellow Card Scheme, which monitors the safety of medicines in the UK. Patients can also report side effects directly via the Yellow Card website or app.

Other Side Effects of Tadalafil to Be Aware Of

Beyond hearing-related effects, tadalafil is associated with a range of other adverse effects, most of which are mild to moderate and related to its vasodilatory properties. Understanding these can help patients recognise normal versus concerning reactions.

Common side effects (affecting up to 1 in 10 people) include:

• Headache: Often the most frequently reported side effect, resulting from vasodilation of cerebral blood vessels

• Flushing: Redness or warmth in the face and neck

• Indigestion or dyspepsia: Stomach discomfort or acid reflux

• Nasal congestion: Blocked or runny nose due to vasodilation of nasal blood vessels

• Back pain and muscle aches: Typically mild and self-limiting, thought to be related to PDE11 inhibition in skeletal muscle

These effects are usually transient and resolve without intervention. Tadalafil can be taken with or without food.

Less common but more serious side effects require immediate medical attention:

• Priapism: A prolonged, painful erection lasting more than four hours. This is a medical emergency requiring urgent treatment to prevent permanent damage to penile tissue. Seek immediate help at A&E.

• Sudden vision loss: Tadalafil has been associated with non-arteritic anterior ischaemic optic neuropathy (NAION), a rare condition causing sudden vision impairment. Stop the medication and seek urgent medical advice.

• Chest pain or cardiovascular symptoms: Particularly during sexual activity. This may indicate underlying cardiac issues and warrants immediate assessment.

• Severe allergic reactions: Including rash, swelling of the face or throat, and difficulty breathing.

Drug interactions are also important. Tadalafil is contraindicated with nitrates (used for angina), nicorandil, and guanylate cyclase stimulators (e.g., riociguat), as these combinations can cause a dangerous drop in blood pressure. This includes recreational nitrates ('poppers' such as amyl nitrite). Alpha-blockers used for BPH or hypertension may also interact, requiring careful dose adjustment and established haemodynamic stability before co-administration (doxazosin poses a particular risk).

Tadalafil is metabolised by CYP3A4 enzymes, so strong inhibitors (e.g., ketoconazole, ritonavir) may increase tadalafil levels, while inducers (e.g., rifampicin) may reduce effectiveness. Grapefruit juice should be avoided as it can affect drug metabolism. Do not take tadalafil more than once per day, and use caution with excessive alcohol due to the risk of hypotension.

NICE recommends that men prescribed PDE5 inhibitors receive appropriate counselling about potential side effects, contraindications, and when to seek help. Regular review is advisable, particularly for those on long-term therapy or with multiple comorbidities.

Frequently Asked Questions