Erectile dysfunction therapy drugs

Erectile dysfunction therapy drugs

Erectile dysfunction therapy drugs treat penile erectile dysfunction that results from a lack of blood flowing through the corpus cavernosum. This type of erectile dysfunction usually stems from vascular and neurologic conditions. Drugs used for erectile dysfunction include alprostadil, sildenafil, tadalafil, and vardenafil.

Warning!

Adverse reactions to urinary tract antispasmodics

Possible adverse reactions to urinary tract antispasmodics include:

• blurred vision
• headache
• somnolence
• urinary retention
• dry mouth
• dyspepsia
• constipation
• nausea
• vomiting
• weight gain
• pain
• acute and secondary angle-closure glaucoma.

Pharmacokinetics

Erectile dysfunction drugs are well absorbed in the GI tract. Distribution of these drugs isn’t known. The majority of these drugs’including sildenafil, tadalafil, and vardenafil’are given orally, metabolized in the liver, and excreted in feces.

An exceptional drug

Alprostadil is the exception: it’s administered directly into the corpus cavernosum, metabolized in the lungs, and excreted in urine.

Pharmacodynamics

Sildenafil, tadalafil, and vardenafil selectively inhibit the phosphodiesterase type 5 receptors, which causes an increase in blood levels of nitric oxide. This increase in nitric oxide levels activates the cGMP enzyme, which relaxes smooth muscles and allows blood to flow into the corpus cavernosum, causing an erection.

Alprostadil acts locally, promoting smooth muscle relaxation, which causes an increase in blood flow to the corpus cavernosum and produces an erection.

Warning!

Adverse reactions to erectile dysfunction drugs

Adverse reactions to erectile dysfunction drugs include:

• decreased supine blood pressure and cardiac output
• increased risk of cardiovascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmias, cerebrovascular hemorrhage, transient ischemic attack, and hypertension
• headache
• dizziness
• flushing
• dyspepsia
• vision changes
• prolonged erections (more than 4 hours), which can result in irreversible damage to erectile tissue
• penile pain (with alprostadil).

Pharmacotherapeutics

Alprostadil, sildenafil, tadalafil, and vardenafil are all used in the treatment of erectile dysfunction. Sildenafil is also indicated for the treatment of pulmonary arterial hypertension.

Drug interactions

Erectile dysfunction drugs may interact with other drugs in the following ways:

• Nitrates and alpha-adrenergic blockers used in combination with erectile dysfunction drugs may cause severe hypotension and potentially serious cardiac events.
• Ketoconazole, itraconazole, and erythromycin may result in increased levels of vardenafil or tadalafil.
• Protease inhibitors, such as indinavir or ritonavir, may cause increased tadalafil or vardenafil levels