November 29, 2022

Drug therapy of Erectile Dysfunction (ED)

By admin

Oral drug therapy

Oral drug The erect penis has always been a symbol of masculinity and sexual strength. Although erectile dysfunction is not a life-threatening condition, any man will painfully experience problems associated with erectile dysfunction, therefore, for centuries, erectile dysfunction (ED) treatments have aroused interest. In the absence of any specific correctable etiology, ED treatment is more empirical and is carried out in stages. But at the same time, treatment should be etiological and pathogenetic. ED is not a diagnosis, but a symptom, so the patient may need a comprehensive examination to determine the etiology of the disease. First of all, this applies to patients with diabetes mellitus, arterial hypertension and metabolic syndrome. And only if the patient’s examination did not reveal the causes of ED, treatment may be symptomatic.

PDE-5 inhibitors

The use of PDE-5 inhibitors has greatly changed the approach to the treatment of ED and produced a “Sexual revolution”. To date, there are four selective inhibitors approved for the treatment of ED on the US market:

Sildenafil

Sildenafil is the first PDE-5 inhibitor that appeared on the market in 1998. The drug is available in dosages of 25, 50 and 100 mg. The recommended starting dose is 50 mg, followed by an increase or decrease in the dosage, depending on the patient’s needs or side effects. The maximum effect develops 30-60 minutes after taking drugs and can last up to 12 hours. The subtleties of pharmacokinetics and the likelihood of side effects are presented in Tables 2 and 3, respectively.

Tadalafil

Tadalafil The effect of the drug begins 30 minutes after ingestion and lasts for 36 hours, maximum effectiveness is achieved after 2 hours, regardless of food intake. The dose is 10-20 mg, but you should start with 10 mg, followed by individual selection.

Vardenafil

Vardenafil
The drug begins to act 30 minutes after ingestion, fatty foods weaken the effect (> 57% fat). Available dosages of the drug are 5, 10 and 20 mg, but you should start with 10 mg. The drug in vitro is 10 times more active than sildenafil, but this does not imply better clinical efficacy.

Avanafil

Avanafil is a highly selective PDE-5 inhibitor, available since 2013. High selectivity allows it to be used for the treatment of ED with a minimum of side effects. The drug is available in dosages of 50, 100 and 200 mg. The recommended starting dose is 100 mg 15-30 minutes before sexual activity. The subtleties of pharmacokinetics and the likelihood of side effects are presented in Tables 2 and 3, respectively. Taking the drug with food may delay the onset of the effect compared to taking it on an empty stomach, but dietary fats do not have a serious effect on the absorption of the drug in the gastrointestinal tract.

How does it work?

Inhibitors of the enzyme PDE-5 prevent the hydrolysis of cAMP, which leads to relaxation of the MMC of cavernous and cavernous bodies and filling the latter with blood. When taking ED medications, the time of peak concentration in blood plasma should be taken into account and the patient should be instructed: the maximum concentration should coincide with the time of sexual intercourse. The absorption of sildenafil and vardenafil is reduced by lipids coming from food, so the drugs should be taken on an empty stomach. It is also necessary to explain to patients that in order to achieve a drug effect, PDE-5 inhibitors require sexual stimulation (both mental and physical). Patients receiving ED medications should be warned about possible side effects, such as headache, palpitations, nasal congestion, visual disturbances, myalgia (more often when using tadalafil). The use of PDE-5 inhibitors together with nitrates can lead to a critical decrease in pressure. Also, when using PDE-5 inhibitors and α-blockers (usually in the treatment of BPH), the interval between ED medications should be at least 4 hours. Priapism (erection of more than 4 hours) is a rare complication (approximately 0.1%). In addition, there is limited evidence that PDE-5 inhibitors can cause hearing loss or loss, so other treatments should be suggested for patients who report hearing loss.