It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. Do not stop taking tadalafil without talking to your doctor. Likewise, if you experience side effects, we may recommend that you try a lower dose of Tadalafil. Tadalafil is approved by the FDA to treat erectile dysfunction. Counterfeit medicines can be very dangerous. What if I am taking other drugs? Tadalafil may not be safe for people with certain medical conditions, including people who have had a stroke , have coronary heart disease or retinitis pigmentosa an eye disease.Common tadalafil 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. It is a selective inhibitor of cyclic monosphosphate (cGMP)-specific phosphodiesterase type 5. Cialis was approved by the FDA in It’s generic name is Tadalafil and is . $20 for a single 5-mg oral tablet; $80 for a single or mg oral tablet; Daily generic Cialis (tadalafil) $8 for a daily mg or 5-mg tablet; Generic Cialis (tadalafil) $11 for.