While these are the most common side effects, they remain rare: Sildenafil is generally well-tolerated. Your clinician will want to find the lowest dose of the drug that does the job. The starting sildenafil dose was 50 mg, taken 1 hour before sexual activity, with subsequent adjustment to or 25 mg based on efficacy and safety. You might start on the 50mg sildenafil dose but other dosages are available. Ask your healthcare professional how you should dispose of any medicine you do not use. The maximum dose of Viagra is not prescribed to first timers. Sildenafil 25mg is the lowest dose.Aging Aging Finding The Right Viagra Dose For A Year-Old Male: Dosage Info January 13, Erectile dysfunction (E.D.) happens to men of all ages, but risk is closely related to age. The older you get, the . In fixed dose studies the mg dosage of Sildenafil was found to improve erections for 82% of patients. This is slightly higher than the 50mg dosage (74%) and the 25mg dosage (62%). Although the mg tablet is more potent and the most likely to be effective in giving erectile firmness, because there’s more of the active ingredient in it.  · Medically reviewed by Last updated on Applies to the following strengths: 10 mg/mL; 10 mg/ mL; 20 mg; 25 mg; 50 mg; mg Usual Adult Dose for: Erectile Dysfunction Pulmonary Hypertension Usual Geriatric Dose for: Erectile Dysfunction Additional dosage information: Renal Dose Adjustments Liver Dose .