mechanism. Yohimbe (the herb) and yohimbine
(the active ingredient derived from the herb)
products require a doctor’s prescription in the
United States because they act on the parasympa-
thetic NERVOUS SYSTEM(a division of the autonomic
nervous system that regulates certain involuntary
functions). Yohimbe/yohimbine products are most
effective in men who have mild to moderate neu-
ropathy (nerve damage). The supplement arginine
may also decrease erectile dysfunction by increas-
ing nitric oxide.
Other medications that cause erection are self-
injected into the penis or inserted as tiny supposi-
tories (about the size of a grain of rice) into the
urethral meatus (opening of the URETHRAat the tip
of the penis). These medications contain
alprostadil, a formulation of PROSTAGLANDINS, that
instigates the sequence of events within the penis
that cause it to engorge and stiffen. Unlike oral
PDE inhibitors, these medications do cause erec-
tion regardless of sexual stimulation because they
act directly on the smooth MUSCLEwithin the penis
that causes the corpora cavernosa to relax and fill
with blood. The primary drawback to these med-
ications is their form of administration, which lim-
its their appeal as well as the frequency with
which a man may use them (no more often than
once every five days).
Surgery to repair damaged blood vessels or
insert penile implants is an option for erectile dys-
function that does not respond to medications.
The most commonly used penile implants are a
combination of inflatable tubes, a tiny pump, and
small reservoirs that contain a sterile fluid. The
man activates the pump, usually placed in the
SCROTUMor at the base of the penis, to fill the
tubes to acquire an erection. A valve releases the
fluid back into the reservoir.
Lifestyle modifications Lifestyle modifications
such as weight loss, daily physical exercise, SMOK-
ING CESSATION, and reduced ALCOHOLconsumption
can improve circulation and nerve function. Exer-
cise in particular also helps reduce stress.
Psychologic therapy Counseling or sex therapy
may be helpful when there are emotional factors
at play. These factors may cause erectile dysfunc-
tion or develop because of it and then perpetuate
it. Therapy may be individual or involve the sex-
ual partner.Risk Factors and Preventive Measures
Erectile dysfunction becomes more common after
age 50. The key health risks for erectile dysfunc-
tion are cigarette smoking, OBESITY, diabetes, long-
term ALCOHOLISM, CARDIOVASCULAR DISEASE (CVD),
prostate disease, and kidney disease. Lifestyle sig-
nificantly influences these factors. Lifestyle meas-
ures to reduce these risks include smoking
cessation, nutritious EATING HABITS, daily physical
exercise, moderation in or cessation of alcohol
consumption, and weight management. Medical
measures include management of blood lipid lev-
els (cholesterol and triglycerides) and diligent con-
trol of blood glucose and INSULIN levels in men
who have diabetes through appropriate medica-
tion therapy.
See also AGING, REPRODUCTIVE AND SEXUAL
CHANGES THAT OCCUR WITH; BENIGN PROSTATIC HYPER-
PLASIA(BPH); DIET AND HEALTH; EXERCISE AND HEALTH;
GENERAL ANXIETY DISORDER(GAD); PRIAPISM; PROSTATE
HEALTH; SEXUAL HEALTH; WEIGHT LOSS AND WEIGHT
MANAGEMENT.280 The Reproductive System