In the psychiatric mental health area, anticonvulstants are commonly used to treat bipolar disorder and are also considered mood stabilizer. Valproate, carbamazepine and lamictal have FDA approval for the treatment of bipolar disorder, mania or mixed episodes. Other anticonvulsants, such as topiramate, oxcarbazepine and gapapentin are used off label as adjunctive treatments. In general, the anticonvulsant mood stabilizers have many actions, but it is their effects on ion channels, reducing repetitive firing of action potentials in the nerves, the most directly decreases manic symptoms. In addition, carbamzepine affects the release and reuptake of several neutortransmitters, including norepinephrien, GABA, dopamine and glutamate. It also changes several second messenger systems. No one action has successfully accounted for the anticonvulsants ability to stabilize mood.
The most common side effects of carbamazepine are dizziness, drowsiness, tremor, visual disturbance, nausea, and vomiting. These side effects may be minimized by initiating treatment in low lamictal dosage. Patients should be advised that these symptoms will diminish, but care should be taken when changing positions or performing tasks that require visual alertness. Giving the drug with food may diminish nausea. Adverse reactions include rare, aplastic anemia, agrnulocytosis, severe lamictal rash, rare cardiac problems and AIADH due to hyponatremia.
Valproic acid also causes gastrointestinal disturbance tremor, and lethargy. In addition, it can produce weight gain and alopecia (hair loss). These symptoms are transient and should diminish with the course of treatment. Dietary supplements of zinc and selenium may be helpful to patients experiencing hair loss. Constipation and urinary retention occur in some individuals. It should monitor urinary output and assist patients to increase fluid consumption to decrease constipation.
Benign skin rash, sedation, blurred or double vision, dizziness, nausea, vomiting and other gastrointestinal symptoms are side effects of lamictal. Normally lamictal hair loss is not reported. One can use dietary supplements of zinc and selenium to reduce lamictal hair loss. In rare cases lamictal produces severe, life threatening rashes that usually occur witihn 2 to 8 weeks of treatment. This rash is highest in children. Use of lamictal should be immediately discontinued if a rash is noted.
Transient elevations in liver enzymes occur with both carbmazepine and valproic acid but rarely do symptoms of hepatic injury occur. If the patient reports abnormal pain or show signs of jaundice the prescriber should be notified immediately. Several blood syscrasias are associated with carbanazepine, including aplastic anemia, arganulocytosis and leukopenia. Patients should be advised to report fever sore throat, rash petechiae or brushing immediately. In addition advise patients of the importance of completing routing blood tests throughout treatment. The increased risks for aplastic anemia and agranulocytosis with carbamazepine use still require close monitoring of CBCs during treatment. Valproate and its derivatives have had a similar course of development.
Of the off label mood stabilizers has relatively few lamictal side effects. Topanax carries an increased risk of kidney stone formation. It can also cause a decrease of oral birth control agents. In addition, ongoing ophthalmologic monitoring is required because of reports of acute myopia with secondary glaucoma.