What are they
They are the drugs that are used to induce and maintain the erection of the penis for a sufficient time to allow the performance of sexual intercourse.
They therefore do not constitute a real therapy for erectile dysfunction, but can be used for symptomatic purposes in cases where the dysfunction is not attributable to pathological conditions (neurological, endocrine, metabolic, vascular, psychological) that can be cured, to pharmacological treatments (some antihypertensives, antidepressants, anxiolytics ) that can be substituted either for risk factors (alcohol, smoking) that can be avoided, or in cases where it is not possible to eliminate their causes.
How they work
Drugs for the treatment of erectile dysfunction can be divided into three groups depending on the mechanism of action.
- The most commonly used molecules belong to the class of phosphodiesterase type 5 inhibitors (PDE-5), an enzyme that counteracts the relaxation of the muscles of the penis responsible for the vascular changes that produce erection. These drugs have above all the function of favoring the maintenance of erection after it has been activated by normal sexual arousal.
- Molecules that act instead at the level of the central nervous system, stimulating an area of the hypothalamus involved in the triggering of erection.
- Prostaglandin analogues (a group of molecules that are normally produced by the body) exert a vasodilating effect at the level of the cavernous bodies, inducing erection directly.
What are they?
To the group of PDE-5 inhibitors belong sildenafil, tadalafil and vardenafil.
These drugs should be taken orally 30-60 minutes earlier (or even earlier in the case of tadalafil, which has a prolonged duration of action) than the intended sexual intercourse.
The second type, centrally acting drugs, is apomorphine, recently introduced and currently approved in a formulation to be taken sublingually.
An inhaled formulation (spray) is still being tested.
Apomorphine takes effect more quickly than drugs in the first group, producing an erection 10-20 minutes after taking it.
To the third type of drugs, prostaglandin analogues belongs alprostadil (synthetic preparation corresponding to prostaglandin E1), which should be administered locally, 5-10 minutes before sexual intercourse, by direct injection into the penis (intracavernous injection) or by intraurethral application with a special device (such modes of administration require initial training that must be followed by the doctor).
| Drug | Timing for recruitment |
|---|---|
| PDE-5 inhibitors | 30-60 minutes before sexual intercourse (or even earlier in the case of tadalafil) |
| Centrally acting drugs | 10-20 minutes before sexual intercourse |
| Prostaglandin analogues | 5-10 minutes before sexual intercourse |
Contraindications and side effects
PDE-5 inhibitor drugs and apomorphine all have – although to different degrees – precise contraindications (the main ones are cardiovascular diseases, liver or kidney failure, retinopathy, optic nerve neuropathies of ischemic origin) and can have various side effects (the most frequent are headache, redness of the face, gastrointestinal disorders, nasal congestion, visual disturbances).
They also interact with numerous other drugs, thus being able to modify the effects of any therapies in place.
The local administration of alprostadil is contraindicated in the presence of anatomical abnormalities of the penis, and depending on the doses used (which must be adjusted case by case) can produce, as a side effect, abnormally prolonged and painful erections.
The use of any medication for erectile dysfunction should therefore be prescribed and carefully supervised by your doctor.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.