Never purchase ED medications from a site or service that doesn’t require a prescription and medical documentation. This increase in blood flow results in a firmer, longer-lasting erection. Your health information should remain between your provider and yourself. Common side effects include headache, facial flushing, indigestion, and dizziness. In some cases, ED can cause a strain on relationships and impact self-esteem. Most companies have an FAQ or shipping policy page you can reference to learn whether discreet packaging is available.heart attack symptoms – chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating. 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. Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash. Here’s what you need to know about generic tadalafil and how to save. Cialis vs. generic tadalafil. Cialis and generic tadalafil are fundamentally the same medication, and the FDA has a rigorous process for ensuring that generics perform just like their brand counterparts. Both Cialis and tadalafil treat ED at the following doses: .