Cialis works by enhancing the effects of one of the chemicals the body normally releases into the penis during sexual arousal. Taking too much can pose serious health risks and might even lead to overdose. However, if it’s already almost time for your next pill, skip the missed dose and continue on your regular schedule. One of the first questions most men ask is about how much tadalafil to take. If you miss a dose of tadalafil, just take the missed dose as soon as possible. Do you know what you need and are ready to purchase? This allows an increase of blood flow into the penis.Don’t take tadalafil more than once per day. When using with other drugs: If you’re taking tadalafil with finasteride (another drug used to treat BPH), your tadalafil dosage will be 5 mg once. To find out how the costs of Cialis and tadalafil compare, talk with your doctor, pharmacist, or insurance provider. If you’ve been prescribed Cialis and you’re interested in taking . Common Cialis side effects may include: headache; flushing (warmth, redness, or tingly feeling); nausea, upset stomach; stuffy nose; or. muscle pain, back pain, pain in your arms, legs, or back. This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.