Prostaglandin E1 (PGE1), also known as alprostadil, is a naturally occurring

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...

which is used as a medication. In infants with congenital heart defects, it is delivered by slow injection into a vein to open the ductus arteriosus until surgery can be carried out. By injection into the penis or placement in the urethra, it is used to treat

erectile dysfunction Erectile dysfunction (ED), also called impotence, is the type of sexual dysfunction in which the penis fails to become or stay erect during sexual activity. It is the most common sexual problem in men.Cunningham GR, Rosen RC. Overview of male ...

. Common side effects when given to babies include decreased breathing, fever, and low blood pressure. When used for erectile dysfunction side effects may include penile pain, bleeding at the site of injection, and prolonged erection (priapism). Prostaglandin E1 is in the

vasodilator Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...

family of medications. It works by opening

blood vessels The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...

and relaxing

smooth muscle Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit mus ...

. Prostaglandin E1 was isolated in 1957 and approved for medical use in the United States in 1981. It is on the World Health Organization's List of Essential Medicines.

Medical uses

Patent ductus arteriosus

Alprostadil is also used in maintaining a patent ductus arteriosus in newborns. This is primarily useful when the threat of premature closure of the ductus arteriosus exists in an infant with ductal-dependent congenital heart disease, including cyanotic lesions (e.g., hypoplastic left heart syndrome, pulmonary atresia/stenosis, tricuspid atresia/stenosis, transposition of the great arteries) and acyanotic lesions (e.g., coarctation of the aorta, critical aortic stenosis, and interrupted aortic arch).

Sexual dysfunction

Alprostadil is sold in the United States as

urethral suppositories A suppository is a dosage form used to deliver medications by insertion into a body orifice where it dissolves or melts to exert local or systemic effects. There are three types of suppositories, each to insert into a different sections: rectal su ...

and in injectable form. The suppositories are sold under the brand name Muse. The injectable forms are Edex and Caverject. Muse delivers alprostadil as a penile suppository, inserted into the urethra, at least ten minutes before the erection is needed. Caverject and Edex are similarly fast-acting, but instead are injected by syringe directly into the corpus cavernosum of the penis. Alprostadil is also available as a generic. The major cost is that it must be mixed by a

compounding pharmacy In the field of pharmacy, compounding (performed in compounding pharmacies) is preparation of a custom formulation of a medication to fit a unique need of a patient that cannot be met with commercially available products. This may be done for me ...

and supplies may be difficult to obtain. The different formulations, including Bimix and Trimix, may include papaverine and/or phentolamine. A typical mix might be 30 mg of papaverine, 2 mg of phentolamine, and 20 μg alprostadil. As a generic, it is much less expensive than the packaged injectables. It is premixed and must be kept refrigerated and the user must load a syringe with the quantity needed.Most recently, the compound has been made easily accessible in an applicable topical cream form known as Vitaros. Made by Takeda UK Ltd, it is now available in Europe and contains either 200 or 300 micrograms of alprostadil in 100 mg of cream which is directly administered as a topical cream applied to the urethra in a preloaded delivery device. The tip of the device is placed in the urethral meatus and the cream delivered into the urethra. Clinical trials for the treatment showed positive results in over 3000 men that it was tested on, and unlike other sexual dysfunction medication, it is said to be usable by men with diabetes or heart problems and those who have undergone a prostatectomy. It has no known interactions with food, alcohol or other medications making it safer than other treatments containing alprostadil. Similarly to the Bimix and Trimix injections though, it must be kept under cool temperatures.

Critical limb ischemia

Prostanoids, including alprostadil, do not reduce the risk of limb amputation but may offer a slight improvement in rest-pain and leg ulcer healing in persons with critical limb ischemia.

Contrast-induced nephropathy

Preventative administration of alprostadil may reduce the risk of kidney injury (specifically contrast-induced nephropathy) in persons having cardiac angiography or percutaneous coronary intervention.

Adverse effects

* Accidental injury (Muse only) *

Apnea Apnea, BrE: apnoea, is the temporal cessation of breathing. During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. Depending on how blocked the airways are ( patency), there ...

* Bleeding: ** Cerebral ** Urethral *

Bradycardia Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, a ...

* Cardiac arrest * Congestive heart failure * Cortical proliferation of long bones * Diarrhea *

Disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts o ...

* Edema * Fever * Flushing * Hyperemia * Hypotension * Injection-site haematoma * Injection-site ecchymosis (Caverject only) * Pain: ** Back ** Pelvic ** Penile ** Testicular (Muse only) ** Urethral * Prolonged erection * Penile fibrosis * Second-degree heart block * Seizures * Sepsis * Shock * Spasm of right ventricle infundibulum *

Supraventricular tachycardia Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which start within the lower cham ...

* Tachycardia * Ventricular fibrillation * Urethral burning * Uterine rupture

Biosynthesis

Prostaglandin E1 is biosynthesized on an as-needed basis from

dihomo-γ-linolenic acid Dihomo-γ-linolenic acid (DGLA) is a 20-carbon ω−6 fatty acid. (also called, cis,cis,cis-8,11,14-Eicosatrienoic acid) In physiological literature, it is given the name 20:3 (ω−6). DGLA is a carboxylic acid with a 20-carbon chain and thre ...

(an omega-6 fatty acid) in healthy humans without

coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pla ...

and/or a genetic disorder.

Other versions

Misoprostol is another synthetic prostaglandin E₁ analog used to prevent gastric ulcers when taken on a continuous basis, to treat missed miscarriage, to induce labor, and to induce abortion.

References

External links

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