PDE5 Inhibitors Drug Class

A drug is classified on the basis of the chemistry of its active ingredient or on the basis of which a particular disease is treated. Each drug can have one or more classes. A drug class comprises of a group of drugs that have something in common, but not identical. PDE5 inhibitors belong to the class Phosphodiesterase type 5 (PDE5) inhibitor. PDE5 inhibitors are a kind of targeted therapy used to treat people with erectile dysfunction (ED) and pulmonary hypertension (PH). PDE5 inhibitor drugs are taken in the form of tablets. PDE5 drugs can be taken by men at any age who are in good health. However, for people who are taking nitrate drugs or alpha-blockers for high blood pressure should avoid PDE5 inhibitors.

PDE5 Inhibitors Drugs

Below you will find a list of drugs that fall under the class of PDE5 Inhibitors.

PDE5 Inhibitors Uses

PDE5 (phosphodiesterase 5) inhibitor drugs are used in the treatment of several health problems such as erectile dysfunction in diabetic patients, pulmonary hypertension, and benign prostatic hyperplasia (BPH), to name only a few. The cGMP-dependent phosphodiesterase is important for smooth muscle relaxation and vasodilation. However, there is an enzyme, called cGMP-dependent phosphodiesterase, which is found in the corpus cavernosum of the penis and vascular smooth muscle.

This enzyme breaks down cGMP that produce in response to higher nitric oxide concentration. Increased concentration of intracellular cGMP inhibits calcium entry into the cell, thus decreases intracellular calcium concentrations and causes smooth muscle relaxation. PDE5 inhibitors maintain cGMP concentration by inhibiting the enzyme cGMP-dependent phosphodiesterase.

PDE5 Inhibitors Side Effects

Some of the most common effects of PDE5 inhibitors include headache, dizziness, back pain, upset stomach, cutaneous flushing and nasal congestion. Besides, there are several other severe side effects associated with PDE5 inhibitors. Some of the effects have been discussed below:

Effects on Vision

A significantly lower percentage of men who used these drugs have been reported to have vision problems such as a temporary increase in brightness, seeing a blue haze or vision loss in a very rare case. People, who use PDE5 regularly, are advised to see an ophthalmologist at frequent intervals.

Effects on the Heart

Viagra such as sildenafil can suddenly lower the blood pressure when taken with nitrate drugs. It is, therefore, advised to consult a doctor before taking this drug.

Effects on Hearing

Some men have experienced hearing loss symptoms such as dizziness and ringing in the ears. Anyone experiencing these symptoms is advised to immediately contact a doctor.


Some people have been reported to have experienced seizures after taking PDE5 inhibitor drugs such as sildenafil. It is always better to consult a doctor before taking this medicine.

PDE5 Inhibitors Interactions

Severe interactions have been found with nitrate drugs such as nitroglycerin. Besides, PDE5 inhibitors may interact with other drugs such as erythromycin, which is an antibiotic. Candidates with severe heart disease, uncontrolled diabetes, severe heart failure or uncontrolled hypertension are not suitable for PDE5 inhibitors. It is always better to consult a doctor before taking PDE5 drugs to avoid severe interactions, if any.