Thalidomide, Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

Another reason is the apparent ability of thalidomide to inhibit the growth of new blood vessels. This could prove useful in cases of macular degeneration, which results from an overgrowth of new blood vessels in the central portion of the retina where focus is controlled.

In the AIDS arena, thalidomide may have the ability to combat aphthous lesions in the mouth and esophagus. In AIDS patients, these ulcerous sores are large, deep and painful. They are also debilitating, and may lead to malnutrition because the patient cannot eat.

With so many diverse applications being tested, FDA originated a Thalidomide Working Group in 1994 to provide consistency among the agency's various review divisions with a particular emphasis on safety monitoring.

Thalidomide is not approved for use in the United States; however, in appropriate circumstances FDA allows restricted investigational use of the drug to treat the diseases now under clinical trials. Over the years, thalidomide has been given to hundreds of patients under FDA's program for single-patient investigational new drug applications (INDs). However, as Birnkrant points out, "We're now moving from a state of issuing compassionate INDs for thalidomide to a state where there are actual clinical trials going on."

Given the known serious toxicities of the drug, those people participating in the investigational programs are given strong and unambiguous warnings. Female patients are advised that taking even one thalidomide pill can cause birth defects. They are further warned:

• You must not take thalidomide if you cannot avoid pregnancy.
• Before taking any thalidomide you must have a blood or urine test done by your doctor that shows you are not pregnant.
• You must abstain from sexual intercourse or use two highly effective birth control methods at the same time for at least one month prior to receiving thalidomide, and continuing regularly thereafter, until one month after the last dose of thalidomide.

Female patients are also reminded that no method of birth control is completely reliable except for abstinence, and that if the patient does not practice abstinence or has not had a hysterectomy, she must use birth control even if she believes that she cannot become pregnant. She must also refrain from any other activity, such as fertilization methods, that could result in pregnancy. She is also warned not to take the drug if she is nursing a baby.

A female patient must immediately stop taking thalidomide under the following circumstances:

• If she has a late or an irregular menstrual period.
• If she stops practicing abstinence.
• If she stops using birth control.
• If she thinks that she is pregnant.
• If she does become pregnant.

A female patient is also required to have a blood or urine test for pregnancy on a monthly basis or more frequently if she has irregular menstrual periods. Pregnancy testing will also be done if the patient experiences vaginal bleeding, or if she misses a menstrual period.

Male patients must be willing to abstain from sexual intercourse or use a condom during intercourse while they are taking thalidomide and for at least one month after the last dose, because it is not known if the drug is present in semen.

In general, all patients are reminded that thalidomide has been prescribed for the individual only, and must not be shared with, or given to, others. In addition:

Thalidomide often causes drowsiness. The patient should avoid drinking alcohol or taking other medications that might induce sleepiness. Also, the ability to operate machinery or participate in activities requiring alertness and clear judgment may be impaired while taking thalidomide.

Thalidomide causes nerve damage in some patients. In some cases, the nerve damage has proved irreversible even after treatment with the drug is discontinued. Symptoms of nerve damage include numbness or tingling in the arms, hands, legs, and feet.

Any such side effects should be reported by the patient to his or her doctor, as well as additional side effects such as: mood changes, dry mouth, headache, nausea, constipation, increased appetite, puffiness of the face and limbs, dry skin, itching, low white blood cell count, thyroid problems, blood sugar that is too high or too low, and slow heartbeat.

Although there are risks involved in an investigational program with a teratogenic drug like thalidomide, Birnkrant points out that it is important to explain to the public and to the patients just how the drug should be used. "The goal is to minimize the risk, recognizing that it may never be zero."

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.