Bexarotene

Definition

Bexarotene, also known by the brand name Targretin, is an antitumor agent of the class known as retinoids.

Purpose

Bexarotene is used to treat cutaneous T-cell lymphomas that have not responded to therapy with other drugs commonly used to treat this disease. A cutaneous T-cell lymphoma is a tumor found on the skin and originates from cells of the immune system.

Description

Bexarotene is one of a group of drugs called retinoids, a derivative of vitamin A. Retinoids are involved with the process of stimulating some cells to mature to normal cells, and with inhibiting some cells from growing. It is thought that bexarotene binds to the retinoic acid receptors on cells. This binding ultimately results in the regulation of the growth and maturation of the cells.

Recommended dosage

Doses vary from individual to individual and depend on body weight and other factors. Bexarotene is taken by mouth in capsule form. The initial dose is usually 300 mg per square meter of body surface area per day. The maintenance dose is 300 to 400 mg per square meter of body surface area per day.

Precautions

Pregnant women should not take bexarotene. The risks of fetal abnormality are high, and women should take precautions to ensure they do not become pregnant.

Patients should limit their intake of vitamin A supplements to avoid additive toxic effects with bexarotene, which is a vitamin A derivative. Patients with diabetes and who are receiving insulin or oral medications for their diabetes are usually prescribed bexarotene with caution, and their blood sugar should be frequently monitored. Bexarotene may enhance the effects of the medications for diabetes, and patients may have low blood sugar levels.

Patients taking bexarotene may experience photosensitivity, or increased sensitivity to sunlight. In order to prevent rash, itching, or severe sunburn, patients should avoid direct sunlight exposure, avoid sunlamps or tanning beds, use sunblock lotion that is SPF 15 or greater, and wear a lip balm that is SPF 15 or greater. Patients should also wear sunglasses, a hat, and garments covering as much skin as possible when outside.

Side effects

The most common side effects of bexarotene increased levels of triglycerides, cholesterol, and high-density lipoprotein cholesterol. Some patients may require medications to control this rise in lipids. Decreased thyroid function also occurs frequently, and thyroid hormone replacement therapy may be necessary in some patients. Other common side effects include headaches, rash, red and scaly inflammation of the skin, hair loss (alopecia), decreased red and white blood cells, and cataracts of the eyes. Patients should have eye examinations if they have any visual difficulties. Patients may be at increased risk of infections due to decreased white blood cells and experience fatigue due to decreased red blood cells. Other less common side effects include fluid gain causing swelling of extremities, insomnia, chills, fever, anorexia, nausea and vomiting, abdominal pain, back pain, flu-like symptoms, and dry skin. As with all medications, patients experiencing any of these (or other) side effects should notify their physician.

Interactions

There are an extremely large number of drugs that interact with bexarotene. Patients should consult their physician, nurse, or pharmacist about any medications they are taking before beginning a course of Bexarotene. Many physicians recommend bringing the containers with the names of all the drugs the patient is taking to their appointment with the physician.

Michael Zuck, Ph.D.

Anorexia

—Loss of appetite.

Lipids

—Fatlike substances stored in the body that serve as a source of fuel and are important constituents of cell structure.

Photosensitivity

—An abnormal cutaneous response to sunlight or filtered or artificial light.