Malegra 100 mg (sildenafil 100 mg) usually requires some planning before use because it is taken before sexual activity, not as a daily medicine for most people. It is commonly taken about 30–60 minutes before sex. Its effect can last for about 4–6 hours (varies by person). It works only with sexual stimulation; it does not automatically cause an erection. A heavy or high-fat meal can delay its onset, so many people Malegra 100 mg  it on an empty stomach or after a light meal. Do not take more than the prescribed amount or use it more than once in 24 hours. Avoid sildenafil if you use nitrate medicines (for chest pain/heart problems), and use caution with certain blood pressure medicines or alpha-blockers. If you tell me whether you are using Malegra 100 mg for occasional use or comparing it with Tadalista 5 mg (daily tadalafil), I can explain the differences.