Drug class · Reproductive
PDE5 inhibitors
Also known as: phosphodiesterase type 5 inhibitors, phosphodiesterase-5 inhibitors
PDE5 inhibitors are medicines that include sildenafil and tadalafil, used mainly for erection problems. Some are also used for pulmonary hypertension. The NHS warns against combining them with nitrates and poppers because blood pressure can fall sharply.
- Biological target
- Phosphodiesterase type 5 (PDE5)
- Also called
- phosphodiesterase type 5 inhibitors, phosphodiesterase-5 inhibitors
Mechanism of action
StatPearls says these drugs stop the PDE5 enzyme from breaking down cGMP, a chemical messenger. StatPearls also says nitrates and PDE5 inhibitors both cause blood vessels to widen, so using them together can cause severe low blood pressure.
Members of the class
Members with a page on this site are linked.
Conditions treated
Class effects
- Headache, indigestion and a blocked nose are among the side effects the NHS lists for sildenafil and tadalafil.
- A painful or prolonged erection and sudden changes in sight or hearing are listed as serious.
Cautions
- StatPearls says combining PDE5 inhibitors with nitrates is contraindicated because of the risk of profound and potentially life-threatening low blood pressure.
- The NHS lists poppers and some illegal drugs as raising the risk of serious side effects.
- A recent heart attack or stroke is among the reasons the NHS lists against use of sildenafil and tadalafil.
- A review says alpha-blockers call for caution with PDE5 inhibitors.
Class warnings
- Combining a PDE5 inhibitor with nitrates can cause a dangerous fall in blood pressure. UK
- Sudden loss of vision or hearing needs a call to a doctor right away. US
Class interactions
| With | Effect | Source |
|---|---|---|
| Nitrates, such as GTN | A dangerous fall in blood pressure; the NHS says sildenafil is not usually prescribed with nitrates, and the same warning applies to tadalafil. | UK |
| Poppers (amyl nitrate) | A higher risk of serious side effects. | UK |
| Illegal drugs such as amphetamines, ecstasy and cocaine | The NHS says these can increase the risk of serious side effects. | UK |
Open the Drug Interaction Checker
Connected pages in detail
What each linked page on Anatomy Nexus covers, in a line, for PDE5 inhibitors.
Conditions
- Coronary artery disease Narrowing of the coronary arteries by fatty plaque (atherosclerosis), limiting blood flow to the heart muscle.
- Heart attack (myocardial infarction) Death of heart muscle because a coronary artery is suddenly blocked, usually by a clot forming on a ruptured plaque.
- Stroke Sudden loss of brain function because blood supply to part of the brain is interrupted, by a blocked artery (ischaemic.
- Type 2 diabetes A metabolic disease in which the body's cells respond poorly to insulin (insulin resistance) and the pancreas gradually fails to compensate.
Medications
- Sildenafil Sildenafil is a medicine used to treat erection problems and, sometimes, pulmonary hypertension.
- Tadalafil Tadalafil is a medicine mainly used to treat erection problems.
Educational content. A drug class page describes what a family of medicines has in common. Individual medicines differ in dose, licensing and interactions; treatment choices belong to a prescriber.