In their experiments, the researchers used mice bred to mimic Duchenne muscular dystrophy. Then the scientists gave the rodents doses of Viagra comparable to those taken by men for erectile dysfunction. This is another test of nerve function in the shaft of the penis. This test uses electromagnetic vibration to evaluate sensitivity. A decreased perception of vibration may indicate nerve damage in the pelvic area, which can lead to impotence. generic viagra here best price viagra buy Before ordering any tests, your doctor will review your medical history and perform a thorough physical examination. The doctor will also "interview" you about your personal and sexual history. Some of these questions will be very personal and may feel intrusive. However, it is important that you answer these questions honestly. The questions asked may include: Of the 99 men reviewed, the optimal dose for achieving erection satisfactory for sexual intercourse was: 25 mg � 6 (6.1%), 50 mg � 44 (44.4%), 75 mg � 1 (1%) and 100 mg � 38 (38.4%). The side effects most commonly encountered were headache (24%), flushing (16%), dyspepsia (12%), nasal congestion (10%), abnormal vision (5%), thirst (2%) and dazed feeling (2%). Uncommon side effects included palpitations (1), dizziness (1) and penile pain (1). Severe side effects necessitated withdrawal of Viagra in 2 patients (1 was a 'success' and the other a 'failure'). Out of 53 men who reported lack of side effects at Visit 2, 6 developed some side effects at Visit 3. Conversely, 11 men who had side effects at Visit 2 reported lack of them at Visit 3. There were no changes in the side effect profile between Visit 3 and Visit 4. Four men with Peyronie's disease had used sildenafil � two reported success with therapy while the other two failed. There were 2 isolated reports of prolonged erection (lasting 20 � 30 minutes) that were painless, which did not recur. There were no serious adverse events or deaths recorded during the trial period. When To Call a Doctor