Laboratory tests see Urine drug screening

Lamictal see Lamotrigine

Lamotrigine

Definition

Lamotrigine is an anticonvulsant drug commonly used to prevent seizures . It is also used as a mood stabilizer in some people with bipolar (manic-depressive) disorder. In the United States, lamotrigine is available under the trade name of Lamictal.

Purpose

Lamotrigine is used to prevent seizures in individuals with seizure disorders. It is also used as a mood stabilizer in people with bipolar disorder .

Description

The United States Food and Drug Administration (FDA) approved Lamotrigine in 1994. This drug appears to suppress the activity of neurons (nerve cells) in the brain . By stabilizing neurons, lamotrigine prevents seizure activity and may also stabilize abnormal mood swings.

Lamotrigine is available as both oral and chewable tablets. It is broken down in the liver.

Recommended dosage

The dosage of lamotrigine varies depending upon the age and weight of the patient, other medications that the patient is taking, and whether the patient has heart, liver, or kidney disease. It is common for patients to start with a low dosage of lamotrigine. The dosage is then increased slowly over several weeks to help prevent side effects. The dosage may be adjusted frequently by the prescribing physician.

A common dose for an adult who takes no other medications and has no other diseases is 150–250 mg taken twice daily.

Precautions

A serious and permanently disfiguring rash may occur as a result of lamotrigine. The rash, which is a symptom of a systemic reaction to the drug, may be life-threatening. If a rash occurs, a doctor should be contacted immediately, and the drug stopped. People who have experienced any kind of rash while taking lamotrigine should never take the drug again.

Lamotrigine should be used with physician supervision after assessing the risks and benefits in people with heart, kidney, or liver disease. The dosage is usually reduced in these individuals.

Side effects

Side effects that occur in more than 10% of people taking lamotrigine are: headache, dizziness, unsteadiness while walking, blurred vision, double vision, nausea, cold-like symptoms involving runny noses or sore throats, and infections.

Although relatively rare, any rash that develops while taking lamotrigine should be evaluated by a health care professional, since life-threatening rashes may occur.

Other side effects include confusion, impaired memory, sleep disorders , nonspecific pain all over the body, and disruption of menstrual cycles.

Interactions

Some drugs can decrease the levels of lamotrigine in the body. This may make the drug less effective. Examples include carbamazepine , phenobarbital, primidone, phenytoin, and valproic acid . Interestingly, valproic acid and its close relative, divalproex sodium , have also been reported to increase lamotrigine levels in some people, which could increase the side effects of the drug. When lamotrigine and valproic acid are used together, there is a greater chance that a serious rash may develop. Very specific dosage guidelines must be followed when these two drugs are used at the same time.

Lamotrigine may increase the levels of carbamazepine in the body, increasing adverse effects associated with carbamazepine.

An increased risk of certain side effects may occur if lamotrigine is used with drugs that inhibit folic acid synthesis, such as methotrexate.

Resources

BOOKS

Ellsworth, Allan J., and others, eds. Mosby's Medical Drug Reference. St. Louis, MO: Mosby, Inc, 1999.

Facts and Comparisons Staff. Drug Facts and Comparisons. 6th Edition. St. Louis: Facts and Comparisons; Philadelphia: Lippincott Williams and Wilkins, 2002.

Medical Economics Co. Staff. Physician's Desk Reference. 56th edition. Montvale, NJ: Medical Economics Company, 2002.

Kelly Karpa, RPh, Ph.D.