Isotretinoin

Brand names

• Accutane

Usage

Isotretinoin is used to treat severe acne that has not responded adequately to other treatments, such as oral antibiotics. Because of the risk for potentially serious side effects, isotretinoin is prescribed only as a last resort.

How it works

Isotretinoin decreases the size of and interferes with the functioning of structures in the skin called sebaceous glands. These tiny glands, located along hair shafts all over the body's surface, produce sebum-a thick, oily substance that serves as the skin's natural lubricant. Hormonal activity (during pregnancy, puberty, or menstruation, for example) can stimulate overproduction of sebum by the sebaceous glands so that it is secreted faster than it can exit the pores. This may lead to blockage of the hair follicle and result in the sort of skin lesion that characterizes acne. By thinning the composition of sebum and reducing sebum production (as well as causing other, only partly-understood changes), isotretinoin improves acne.

Side effects

Serious

Severe headache that may occur in conjunction with blurred vision, nausea, and vomiting. Discontinue isotretinoin and contact your doctor immediately as this may be an indication of a very serious condition known as "pseudotumor cerebri," marked by increased pressure within the skull, which may damage the brain. Severe central abdominal pain, penetrating through to the back, may indicate acute pancreatitis (inflammation of the pancreas); call your doctor or get to an emergency room immediately.

Common

Dry, itching, or cracked skin or lips; easy bruising; nosebleeds; dry, red, or inflamed eyes, difficulty wearing contact lenses; increased susceptibility to sunburn; muscle or joint pain. Consult your doctor if such symptoms persist or interfere with daily activities.

Less common

Rashes, peeling of skin on palms and soles, nausea, dizziness, poor night vision (night blindness), cataracts, appearance of small spots or shadows passing slowly across the line of vision ("floaters"), thinning hair, weight loss, swelling in the feet and ankles (known as "edema") due to excess fluid retention in the body tissues, mental depression.

Possible interactions

Other medicaments:

Isotretinoin taken concurrently with:

• carbamazepine (Tegretol) may cause subtherapeutic carbamazepine levels.
• medicines known to increase sensitivity to the sun as these may additively increase sun sensitivity if taken with isotretinoin.
• minocycline may increase risk of severe headache, papilledema and visual changes.
• tetracyclines may cause increased risk of pseudotumor cerebri.

Foods:

Increases absorption and may be a good mechanism to maintain blood levels.

Herbal medicines or minerals:

Caution: St. John's wort may also cause extreme reactions to the sun. Additive photosensitivity may be possible. Medicinal yeast has a Commission E monograph indication for acne, but has not been studied with isotretinoin. Talk to your doctor before combining any herbals with prescription medicines.

Exposure to sun:

This medicament can cause photosensitivity.

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