When prescribing Viagra, your doctor will consider a few essential factors such as smoking, alcoholism, addiction , etc. This medicine also works best when you take it an hour before sex on an empty stomach. Oral medicine for ED also might not be safe or work well if you have: Very low blood pressure, called hypotension, or uncontrolled high blood pressure, called hypertension. He or she must be a licensed practitioner and authorized to prescribe Viagra. Make a list of all medications, vitamins, herbal remedies and supplements you take. What to expect from your doctor Your doctor is likely to ask you a number of questions. · Proper Use. Drug information provided by: Merative, Micromedex ®. Use sildenafil exactly as directed by your doctor. Do not use more of it and do not use it . The safest way to get a prescription for Viagra is from your doctor. You can even do this over a telehealth call (on the phone or computer) in many cases, . Ask your doctor to prescribe brand-name VIAGRA and to indicate “DAW” (Dispense As Written)—or the language used in your state—on all of your VIAGRA prescriptions. Get .