Many medical conditions and medications can cause erectile dysfunction. ED may occur as a side effect of certain drugs. There are a number of prescription and over-the-counter medications that may cause ED as a side effect (Schatzberg and Nemeroff 2004). Medications to treat high blood pressure, antihistamines (for colds or allergies), cancer chemotherapies, and some psychotropic medications (for depression or anxiety) are among the more common agents, although any medication may be suspected until you can rule it out. Drug side-effect ED is acquired and occurs in all sexual situations.
Blood Pressure Medications (Antihypertensives)
Hypertension (high blood pressure) may be a risk factor for erectile dysfunction, and several blood pressure medications (antihypertensives) have been described as causing erectile dysfunction, most notably beta-blockers, such as metoprolol, atenolol, and labetolol, and thiazide diuretics such as hydrochlorothiazide. The only thiazide diuretic that has not been associated with erectile dysfunction is indapamide. In a study comparing five different blood pressure medications for the treatment of mild hypertension, the highest incidence of erectile dysfunction (17%), was noted in men taking the thiazide diuretic chlorthalidone (Hygroton), and the lowest rate of erectile trouble was noted with the alpha-blocker doxazosin (Cardura). In fact, in this study, some men with pre-existing erectile troubles noted an improvement in erectile function while they were taking doxazosin.
Blood Pressure Medications (Beta-Blockers)
Another group of blood pressure medications, the beta-blockers, have also been associated with erectile dysfunction. The incidence of erectile dysfunction in men taking the beta-blocker propranolol is as high as 15%. Propranolol (Indeval) and other beta-blockers may lower the serum testosterone level to a lesser degree. Clonidine (Catapres), another blood pressure medication, is also associated with an increased incidence of erectile dysfunction.
The incidence of erectile dysfunction in patients taking antidepressants has been reported to be as high as 35%. Tricyclic antidepressants, such as imipramine (Tofranil), amitriptyline (Elavil), protriptyline (Concordin), and clomipramine (Anafranil), have been reported to cause erectile dysfunction. It appears that they affect ejaculatory function more than erectile function. Selective serotonin reuptake inhibitors (SSRIs) were initially thought to have less of an effect on erectile function; however, studies suggest that 50% of men who are taking SSRIs may experience erectile dysfunction. There have been reports of erectile dysfunction being associated with fluvoxamine (Luvox), fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil). In rare cases, erectile dysfunction has improved with SSRI use. Antipsychotics such as thioridazine (Mellaril), fluphenazine (Prolixin), and thiothixene (Navane) have also been associated with erectile dysfunction, with up to 44% men taking thioridazine reporting erectile dysfunction. Benzodiazepines, used to treat such conditions as post-traumatic stress disorder, may also cause erectile dysfunction. Clonazepam (Klonopin) use has been associated with a 43% incidence of erectile dysfunction, whereas the other benzodiazepines and the tranquilizers diazepam (Valium), lorazepam (Ativan), and alprazolam (Xanax) have not been associated with erectile dysfunction.
Cimetidine (Tagamet), a histamine2-antagonist used for gastrointestinal irritation, has been reported to cause erectile dysfunction in 40% of men. It is known to prevent testosterone from functioning and may also increase prolactin levels, which can lower testosterone levels, decrease libido, and affect erectile function. The other histamine2-antagonists, ranitidine (Zantac) and famotidine (Pepcid), do not have the same effect on testosterone and are not as frequently associated with erectile dysfunction.
Medications used to lower one’s cholesterol (lipid) level may also affect erectile function. Patients taking clofibrate (Atromid-S) often report erectile dysfunction as a side effect (a reaction to the treatment). There are also several reports of erectile dysfunction associated with gemfibrozil (Lopid) use and resolution of the erectile dysfunction with discontinuation of the drug. Similarly, the lipid-lowering medications pravastatin (Pravachol) and lovastatin (Mevacor) have also been associated with erectile dysfunction. Digoxin, a cardiac medication, has also been associated with erectile dysfunction, as have the seizure medications phenytoin (Dilantin), carbamazepine (Tegretol), primidone (Mysoline), and phenobarbitol (10% to 20% incidence).
Hormone therapies for prostate cancer, such as leuprolide (Lupron) and goserelin (Zoladex), orchiectomy (removal of the testicles, in this case, to stop most testosterone production), and estrogen, have a negative effect on erectile function. The medication ketoconazole, if taken in large quantities, may also affect testosterone production and affect erectile function.
Anabolic steroids, used by body builders and athletes to increase their muscle mass, cause testicular atrophy and decrease testosterone production, which may decrease sperm production, decrease libido, and cause erectile dysfunction. If the anabolic steroids are discontinued, it may take 4 months for the testicles to start producing enough testosterone to restore erectile function to normal.