Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them. That was a significant improvement from reports submitted between and in which 20 percent of medication errors were related to drug name confusion. The most common side effects of VIAGRA: headache; flushing; upset stomach; abnormal vision, such as changes in color vision such as having a blue color tinge and blurred vision; stuffy or runny nose; back pain; muscle pain; nausea; dizziness; rash. ED medications can cause side effects, and it’s crucial to have access to a medical provider if needed. A phone or video consultation is sometimes required for legal purposes. Tweet Email When you pick up a prescription of Viagra, Lunesta, Advair, or Paxlovid , you might wonder how drugs get their mystifying brand names. In some patients, the use of VIAGRA with alpha-blockers can lead to a drop in blood pressure or to fainting medicines called HIV protease inhibitors, such as ritonavir Norvir , indinavir sulfate Crixivan , saquinavir Fortovase or Invirase , or atazanavir sulfate Reyataz some types of oral antifungal medicines, such as ketoconazole Nizoral and itraconazole Sporanox some types of antibiotics, such as clarithromycin Biaxin , telithromycin Ketek , or erythromycin other medicines that treat high blood pressure other medicines or treatments for ED VIAGRA contains sildenafil, which is the same medicine found in another drug called REVATIO.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. When you buy an unauthorized sexual enhancement product there is no guarantee that it contains what it says it does, nor is there a guarantee that its ingredients are safe. These products are often labelled as “all natural” and “safe”, but in many cases prescription drugs are added. They may also contain cheap ingredients added as “fillers”. The recommended dosage of Viagra for erectile dysfunction (ED) is 50 mg, taken as needed about 1 hour before sexual activity. You can take it 30 minutes to 4 hours before sexual activity. And you.