hi, thanks for using healthcare magic Erectile dysfunction is a common problem and can be due to psychological, neurological, vascular or hormonal issues. Normally it is evaluated by determining if there are risk factors for ED such as diabetes, hypertension, high cholesterol, family history of heart disease,medication (some medications can cause or worsen ED), psychological history. This is followed by examination and any necessary investigations. It is possible that the dosage of the viagra may need adjusting but you should consult with your doctor first before changing the dose in any way. There are other medications that are similiar to viagra that may work better for you, again it would be best to consult your doctor to obtain a prescription for them.