Acetretin

A detailed overview of the medication Acitretin

Acitretin is a second-generation retinoid primarily used in the treatment of severe psoriasis. It is a metabolite of etretinate, which was previously used for similar indications but has been largely replaced by acitretin due to its more favorable pharmacokinetic profile.

Pharmacology

Acitretin is a retinoid, which means it is a derivative of vitamin A. It works by modulating the growth and differentiation of epithelial cells, which is beneficial in conditions like psoriasis where there is excessive proliferation of skin cells. Acitretin binds to and activates nuclear retinoic acid receptors (RARs), which then regulate gene expression.

Pharmacokinetics

Acitretin is administered orally and has a bioavailability of approximately 60%. It is highly protein-bound (>99%) and is metabolized in the liver. The elimination half-life of acitretin is about 49 hours, but it can be longer in some individuals. The drug is excreted through both feces (34%) and urine (66%).

Clinical Use

Acitretin is primarily indicated for the treatment of severe psoriasis, particularly in cases where other treatments have failed or are not suitable. It is also used in the treatment of other keratinization disorders. Due to its teratogenic effects, acitretin is contraindicated in pregnant women and women who may become pregnant during treatment or within three years after discontinuation.

Side Effects

Common side effects of acitretin include dry skin, lips, and eyes, as well as hair thinning. It can also cause elevated liver enzymes and lipid levels, so regular monitoring is recommended. Due to its teratogenic potential, it is crucial to avoid pregnancy during and after treatment.

Contraindications

Acitretin is contraindicated in:

• Pregnant women or those planning to become pregnant
• Patients with severe liver or kidney dysfunction
• Patients with chronic abnormally elevated blood lipid values

Interactions

Acitretin can interact with other medications, including:

• Methotrexate: Increased risk of hepatotoxicity
• Tetracyclines: Increased risk of intracranial hypertension
• Alcohol: Can lead to the formation of etretinate, which has a much longer half-life

Also see

• Psoriasis
• Retinoid
• Vitamin A
• Etretinate