They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. The bottom line is that if you experience ED, you should talk about it with your doctor, even if you’re embarrassed, because we have a number of ways that we can effectively treat erectile dysfunction. So take comfort in knowing that you are not alone. For many people, a physical exam and answering some basic questions about your medical history is all that is needed. Your healthcare provider may also order blood tests and collect a urine sample to look for health problems that may cause ED.Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is mg. Don’t take sildenafil (Viagra) more than once daily (at any dose). Written by Brian Leonard, PharmD, BCACP, BCGP. Sildenafil is best known as a treatment for ED, the inability to get or keep an erection. Sildenafil is meant to be taken before having sex, with the understanding that its effects last only a few.  · You can take the drug 30 minutes to 4 hours before you anticipate sexual activity. Based on how well you respond to this dosage and any side effects you have, your doctor may either increase your.