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Researchers
are investigating a newer version of drugs that inhibit the enzyme
targeted by Viagra, phosphodiesterase-5 (PDE-5).
Angiotensin-Receptor Blockers for Men with Hypertension
Recent drugs known as angiotensin-receptor blockers (ARBs),
also known as angiotensin II receptor antagonists are being used
to lower blood pressure in men with hypertension. In one study
after 12 weeks of treatment with an ARB called losartan (Cozaar),
88% of hypertensive males with sexual dysfunction reported improvement
in at least one area of sexuality. The number of men reporting
impotence declined from 75.3% to 11.8%. Other ARBs include candesartan
(Atacand), telmisartan (Micardis), and valsartan (Diovan).
Testosterone Replacement Therapy
Replacement Therapy for Hypogonadism. Testosterone replacement
therapy may be effective in inducing puberty in adolescent boys
with hypogonadism and may also be helpful for some adult patients
with the condition. Some experts believe testosterone replacement
therapy also may be helpful for older men whose testosterone
levels are deficient. It may improve bone density, improve energy
and mood, increase muscle mass and weight, and heighten sexual
interest.
Forms of therapy included the following:
Muscle injections using testosterone enanthate (Andryl, Delatestryl)
or cypionate (Andro-Cyp, Depo-Testosterone, Virion) has been
the standard administration.
Testosterone is now available as a skin patch (Testoderm, Testoderm
TTS, Androderm). Depending on the brand, patches may be applied
to the skin of the scrotum every 24 hours or to the abdomen,
back, thighs, or upper arm. In the latter case, two patches are
required every 24 hours. Testoderm and Testoderm TTS may cause
less skin irritation than Androderm. The skin patch achieves
normal testosterone levels in between 67% and 90% of men.
A skin gel (Androgel) is also now available, which in one study
achieved normal testosterone levels in 87% of men. A gel applied
to the penile skin is being investigated for men with hypogonadism
and erectile dysfunction. At this time, however, the gel is applied
only to the same parts of the body as the patch.
Oral forms of testosterone are not recommended because of the
risk for liver damage when taken for long periods of time. The
drug clomiphene has been used successfully for treating hypogonadism
related to excessive exercise. If excessive levels of the hormone
prolactin cause impotence, the drug bromocriptine (Parlodel)
is sometimes helpful.
Testosterone in Men with Normal Levels. Testosterone therapy
is not recommended for men with testosterone levels that are
normal for their age group. In such men, replacement therapy
does not appear to have any benefits for increased bone mass
or muscle strength. There is also some concern that replacement
therapy in men with normal testosterone levels may increase
the risk for the following adverse effects:
Lower HDL (the so-called good cholesterol).
Rapid growth of prostate tumors in men with existing prostate
cancers. (Although some studies indicate that taking testosterone
does not increase the risk for prostate cancer, some experts
remain concerned.)
Lower sperm count.
Possibly cause sleep apnea.
Possible increased risk for polycythemia, an abnormal increase
in red blood cells.
Possible increased risk for benign prostatic hyperplasia.
DHEAS. Dehydroepiandrosterone sulfate (DHEAS) is a male
hormone used in the production of testosterone. Levels of this
hormone decrease as a man ages. In a 2000 study, men under 60
years old with erectile dysfunction tended to have lower DHEAS
levels than their peers. In one small study, those who took DHEAS
for 16 weeks experienced some improvement in erectile dysfunction.
It is available as a supplement, but should not be taken without
the recommendation of a physician. The long-term effects of this
potent hormone are unknown, and may be similar to those of testosterone
replacement.
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