What Is Tadalafil?
Tadalafil is a phosphodiesterase type 5 inhibitor, usually shortened to PDE5 inhibitor. The European Medicines Agency (EMA) describes Cialis as a tadalafil medicine available only on prescription in the European Union. EMA Cialis overview.
Tadalafil inhibits PDE5 and increases cGMP signaling involved in erection. Sexual stimulation is still required; the US Cialis label explains that the medicine has no effect on erection in its absence. US Cialis label, section 12.1.
Cialis and Adcirca: Keep the Indications Separate
The US Cialis label indicates treatment of erectile dysfunction (ED). It also indicates treatment of the signs and symptoms of benign prostatic hyperplasia (BPH), including men with both ED and BPH. US Cialis label, sections 1.1–1.3.
Adcirca has a separate EU indication. EMA describes it as a tadalafil medicine for pulmonary arterial hypertension in adults and children from two years of age with class II or III disease. This separate Adcirca indication does not make Cialis and Adcirca interchangeable. EMA Adcirca overview.
Interactions That Need Particular Attention
The US Cialis label contraindicates use with organic nitrates because tadalafil increases their blood-pressure-lowering effect. This is a prohibited combination in the label, rather than a minor side effect to weigh against convenience. If discussing Cialis with a clinician or pharmacist, identify nitrate medicines explicitly. US Cialis label, section 4.1.
Cialis must also not be used with guanylate cyclase stimulators such as riociguat. This is a separate contraindication from the nitrate warning. Bring the exact names of other medicines to a discussion of tadalafil. US Cialis label, section 4.3.
Alpha-blockers, antihypertensive medicines and substantial alcohol consumption can add to tadalafil-related blood-pressure lowering. These warnings are distinct from the nitrate and riociguat contraindications. Ask a clinician or pharmacist to review the actual combination; do not turn a short interaction summary into a self-directed plan for adjusting medicines. US Cialis label, sections 5.6 and 5.9.
Side Effects and Urgent Warning Signs
EMA lists headache, indigestion, back pain and muscle pain among the most common Cialis adverse effects. EMA Cialis safety overview.
For an erection lasting more than four hours, the US Cialis label directs emergency medical attention, whether or not it is painful. Do not wait for pain before acting on that warning. US Cialis label, section 5.3.
The label also advises stopping PDE5 inhibitors and seeking medical attention for sudden vision loss or a sudden decrease or loss of hearing. This is the action the label gives for those events; it does not establish that tadalafil caused every reported vision or hearing event. US Cialis label, sections 5.4–5.5.
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