Newmen (Tadalafil)

Tadalafil is used in several clinical areas that involve smooth‑muscle relaxation mediated by the nitric‑oxide/cGMP pathway.

• Erectile dysfunction: enhances the ability to achieve and maintain an erection sufficient for sexual activity.
• Benign prostatic hyperplasia: reduces urinary frequency, urgency and weak stream by relaxing prostatic smooth muscle.
• Pulmonary arterial hypertension: improves exercise tolerance and delays disease progression by dilating pulmonary vessels.

• Tadalafil selectively inhibits phosphodiesterase type 5 (PDE5), the enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in smooth‑muscle cells. By preventing cGMP breakdown, intracellular cGMP levels rise, leading to relaxation of smooth muscle in the corpus cavernosum, prostate and pulmonary vasculature, thereby facilitating increased blood flow to these tissues.

Tadalafil may cause a range of adverse reactions, which are generally classified by frequency and severity.

Common Side Effects

• Headache
• Flushing
• Dyspepsia
• Nasal congestion

Serious or Rare Side Effects

• Sudden loss of vision (non‑arteritic anterior ischemic optic neuropathy)
• Priapism (prolonged erection lasting >4 hours)
• Severe hypotension or syncope

When prescribing tadalafil, clinicians should observe several precautionary measures to minimise risk.

• Cardiovascular assessment: evaluate for recent myocardial infarction or unstable angina before use.
• Nitrate use: avoid co‑administration with any nitrate medication.
• Liver and kidney function: adjust therapy in moderate hepatic or severe renal impairment.
• Sexual activity timing: advise patients to wait at least 30 minutes after dosing before intercourse.
• Retinal disease: contraindicated in patients with inherited retinal disorders such as retinitis pigmentosa.
• Store at ambient temperature: keep in the original container, protect from moisture and excessive heat.

Tadalafil interacts with several drug classes, requiring careful review of a patient’s medication list.

Major Interactions (Avoid)

• Nitrates (e.g., nitroglycerin, isosorbide dinitrate): risk of profound hypotension.
• Guanylate cyclase stimulators (e.g., riociguat): additive vasodilatory effect.
• Potent CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase tadalafil exposure.

Moderate Interactions (Monitor Closely)

• Alpha‑blockers (e.g., tamsulosin, doxazosin): may cause additive blood pressure lowering.
• Antihypertensive agents (e.g., beta‑blockers, ACE inhibitors): monitor for excessive hypotension.
• CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce tadalafil efficacy.