Lamotrigine
Lamotrigine
Definition
Lamotrigine is an anticonvulsant medication used in the treatment of epilepsy . Epilepsy is a neurological disorder in which excessive surges of electrical energy are emitted in the brain, causing seizures . Lamotrigine is usually reserved for difficult-to-control seizures that have not responded to other anticonvulsant medications. In psychiatry, lamotrigine is also indicated in the treatment of bipolar disorder (manic-depression).
Purpose
While lamotrigine controls seizures associated with epilepsy, there is no known cure for the disorder. Although the precise mechanism by which lamotrigine exerts its therapeutic effect is unknown, lamotrigine is thought to act at sodium channels in the neuron (nerve cell) to reduce the amount of excitatory neurotransmitters that the nerve cell releases. Neurotransmitters are chemicals that aid in the transfer of nerve impulses from one nerve junction to the next. With decreased levels of these neurotransmitters, the electrical activity in the brain that triggers seizures is reduced.
In the treatment of bipolar disorders, lamotrigine's effect upon neurochemicals stabilizes mood, preventing sudden, unpredictable, and severe episodes of mania and depression .
Description
For the treatment of epilepsy-related seizures, lamotrigine may be used alone or in combination with other anti-epileptic drugs (AEDs) or anticonvulsants . In the United States, lamotrigine is sold under the brand name Lamictal.
Recommended dosage
Lamotrigine is taken orally, in either tablet or chewable form. Chewable tablets may be dispersed into a liquid solution, according to the prescribing physician's instructions. Lamotrigine is prescribed by physicians in varying daily dosages, usually ranging 200–900 mg per day divided into two doses.
Beginning any course of treatment that includes lamotrigine requires a gradual dose-increasing regimen. The safety and effectiveness of lamotrigine in children under age 18 have not been proven; therefore, the drug is seldom used in children. Adults typically take an initial dose for the first two weeks that is slowly increased over time. It may take several weeks to realize the full benefits of lamotrigine, especially in those patients taking lamotrigine for the treatment of bipolar disorders.
A double dose of lamotrigine should not be taken. If a dose is missed, it should be taken as soon as possible. However, if it is within four hours of the next dose, then the missed dose should be skipped. When ending a course of treatment that includes lamotrigine, physicians typically direct patients to gradually taper down their daily dosages over a period of several weeks. Stopping the medicine suddenly may severely alter mood or cause seizures to occur, even in patients taking lamotrigine for the treatment of bipolar disorders.
Precautions
A physician should be consulted before taking lamotrigine with certain non-prescription medications. Patients should avoid alcohol and CNS depressants (medications that make one drowsy or tired, such as antihistimines, sleep medications, and some pain medications), while taking lamotrigine. Lamotrigine can exacerbate the side effects of alcohol and some other medications. Alcohol may also increase the risk or frequency of seizures.
Lamotrigine may not be suitable for persons with a history of liver or kidney disease, depressed renal function, mental illness, anemia, high blood pressure, angina (chest pain), or irregular heartbeats and other heart problems. Before beginning treatment with lamotrigine, patients should notify their physician if they consume a large amount of alcohol, have a history of drug use, are nursing, pregnant, or plan to become pregnant.
Lamotrigine's safety during pregnancy has not been established. Persons taking lamotrigine (and other AEDs or anticonvulsants) should be aware that many AEDs and anticonvulsants cause birth defects. Patients who become pregnant while taking any AED or anticonvulsants should contact their physician immediately.
Side effects
Lamotrigine is generally well tolerated. However, in some patients, lamotrigine may produce some of the traditionally mild side effects associated with anticonvulsants. Headache , nausea, and unusual tiredness and weakness are the most frequently reported side effects of anticonvulsants. Other possible side effects that do not usually require medical attention include:
- mild coordination problems
- mild dizziness
- abdominal pain
- sinus pain
- sleepiness or sleeplessness
- diarrhea or constipation
- heartburn or indigestion
- aching joints and muscles or chills
- unpleasant taste in mouth or dry mouth
Many of these side effects disappear or occur less frequently during treatment as the body adjusts to the medication. However, if any symptoms persist or become too uncomfortable, the prescribing physician should be consulted.
Other, uncommon side effects of lamotrigine can be serious and may indicate an allergic reaction. Severe and potentially life-threatening rashes have occurred during treatment with lamotrigine, occurring approximately once in every 1,000 persons who take the drug. In the unusual event that this rash develops, it normally occurs within the first eight weeks of treatment. A patient taking lamotrigine who experiences any of the following symptoms should contact a physician immediately:
- rash or bluish patches on the skin
- sores in the mouth or around the eyes
- depression or suicidal thoughts
- mood or mental changes, including excessive fear, anxiety, hostility
- general loss of motor skills
- persistent lack of appetite
- altered vision
- difficulty breathing
- chest pain or irregular heartbeat
- faintness or loss of consciousness
- persistent, severe headaches
- persistent fever or pain
Interactions
Lamotrigine may have negative interactions with some antacids, antihistamines, antidepressants, antibiotics, and monoamine oxidase inhibitors (MAOIs). Other medications such as HIV protease inhibitors (indinavir), ritonavir (Norvir), ipratropium (Atrovent), isoniazid, phenobarbital (Luminal, Solfoton), nefazodone, metronidazole, acetazolamide (Diamox), propranolol (Inderal), rifampin (Rifadin, Rimactane), and warfarin may also adversely react with lamotrigine. Oral contraceptives (birth control pills) may decrease the amount of lamotrigine absorbed by the body.
Lamotrigine may be used with other seizure prevention medications, if advised by a physician.
Resources
BOOKS
Devinsky, Orrin, M. D., Epilepsy: Patient and Family Guide, 2nd ed. Philadelphia: F. A. Davis Co., 2001.
Weaver, Donald F. Epilepsy and Seizures: Everything You Need to Know. Toronto: Firefly Books, 2001.
OTHER
"Lamotrigine." Medline Plus. National Library of Medicine. May 6, 2004 (June 1, 2004). <http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202786.html>.
"Lamotrigine." Yale New Haven Health Service Drug Guide. May 6, 2004 (June 1, 2004). <http://yalenewhavenhealth.org/library/healthguide/enus/drugguide/topic.asp?hwid=multumd03809a1>.
ORGANIZATIONS
Epilepsy Foundation. 4351 Garden City Drive, Landover, MD 20785-7223. (800) 332-1000. <http://www.epilepsyfoundation.org>.
American Epilepsy Society. 342 North Main Street, West Hartford, CT 06117-2507. <http://www.aesnet.org>.
Adrienne Wilmoth Lerner
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 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
KEY TERMS
Bipolar disorder —A mental disorder characterized by dramatic, and sometimes rapid mood swings, resulting in both manic and depressive episodes; formerly called manic-depressive disorder.
Folic acid —An essential B-vitamin that humans obtain through diet.
Manic —Referring to mania, a state characterized by excessive activity, excitement or emotion.
Milligram (mg) —One-thousandth of a gram. A gram is the metric measure that equals approximately 0.035 ounces.
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 such as methotrexate, that inhibit folic acid synthesis.
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. Saint 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.
Lamotrigine
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.