Although rare, Viagra (sildenafil),
Cialis (tadalafil)
and Levitra (vardenafil) can cause muscle pain
and unusual skin sensations or paresthesia. In clinical studies, Viagra caused muscle pain and paresthesia in less than 2% of patients. Patients who experience these side effects should stop taking the medication and consult their physician. These medications increase blood flow to the penis by inhibiting the enzyme phosphodiesterase type 5 (PDE5).