Papaverine belongs to a group of medicines called vasodilators, which cause blood vessels to expand, thereby increasing blood flow. Papaverine is used in MS to treat erectile dysfunction. When papaverine is injected into the penis, it produces an erection by increasing blood flow to the penis.
Papaverine should never be used as a sexual aid by men who are not impotent. If improperly used, this medication can cause permanent damage to the penis.
Papaverine is available by prescription and should be used only as directed by your physician, who will instruct you in the proper way to give yourself an injection so that it is simple and essentially pain-free.
Do not use more of this medication or use it more often than it has been prescribed for you. Using too much of this medicine will result in a condition called priapism, in which the erection lasts too long and does not resolve when it should. Permanent damage to the penis can occur if blood flow to the penis is cut off for too long a period of time.
Examine your penis regularly for possible lumps near the injection sites or for curvature of the penis. These may be signs that unwanted tissue is growing (called fibrosis), which should be examined by your physician.
Possible Side Effects
Side effects you should report to your physician so that he or she can adjust the dosage or change the medication: bruising at the injection site; mild burning along the penis; difficulty ejaculating; swelling at the injection site.
Rare side effects that require immediate treatment: erection continuing for more than four hours. If you cannot be seen immediately by your physician, you should go to the emergency room for prompt treatment.