Description

Overview

Tadalafil is a PDE-5 inhibitor used to treat erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (PAH). Unlike Sildenafil (Viagra), Tadalafil has a longer duration of action, lasting up to 36 hours, earning it the nickname “The Weekend Pill.”

It is available in daily low doses for continuous ED and BPH management or as an on-demand higher dose for spontaneous sexual activity.

Mechanism of Action

Tadalafil works by inhibiting the phosphodiesterase-5 (PDE-5) enzyme, which breaks down cyclic guanosine monophosphate (cGMP). By preventing cGMP degradation, it allows for:

• Increased blood flow to the penis, leading to an erection when sexually stimulated
• Relaxation of smooth muscle in the prostate and bladder, improving BPH symptoms
• Vasodilation of pulmonary arteries, reducing blood pressure in PAH patients

Benefits & Indications

1. Erectile Dysfunction (ED)

• Enables strong and sustained erections
• Can be taken daily (2.5 mg or 5 mg) or as needed (10 mg or 20 mg)
• Longer half-life allows spontaneity compared to Sildenafil

2. Benign Prostatic Hyperplasia (BPH)

• Improves urinary flow, reduces urgency and frequency
• Effective at relaxing the smooth muscle in the prostate and bladder

3. Pulmonary Arterial Hypertension (PAH)

• Helps lower pulmonary blood pressure and improve exercise capacity

Possible Side Effects

• Headache, flushing, dizziness
• Nasal congestion and indigestion
• Muscle and back pain
• Hypotension (low blood pressure)
• Vision changes (rare but includes blue-tinted vision and light sensitivity)

Drug Interactions

• Nitrates (e.g., Nitroglycerin): Can cause life-threatening hypotension
• Alpha-blockers (Tamsulosin, Doxazosin): May lead to severe blood pressure drops
• Antifungals and HIV drugs (Ritonavir, Ketoconazole): Can increase Tadalafil blood levels
• Alcohol: Can worsen dizziness and blood pressure drops