What is the difference between Viagra and Cialis?
Last updated September 3, 2026.
Same drug family, different clocks: sildenafil works about 4 hours and prefers an empty stomach (per MedlinePlus: take roughly 1 hour before), while tadalafil can last up to 36 hours per the NHS and also comes as a low daily dose that removes timing entirely. Sildenafil: no more than once in 24 hours, high-fat meals slow it. Tadalafil: food is irrelevant; daily low-dose option suits spontaneity. Shared cautions: the nitrate interaction is dangerous for both, headaches and flushing are the common side effects, and neither works without arousal. Both are generics now, so the price gap mostly closed.
What to do
- Match the drug to the pattern. Planned occasions: sildenafil. Spontaneity: tadalafil.
- Mind the food rule. High-fat meals blunt sildenafil; tadalafil does not care.
- Never mix with nitrates. The dangerous interaction applies to both.
- Ask about daily tadalafil. The timing-free option for frequent activity.
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