Carbamazepine (Tegretol, Taro-Carbamazepine) is a drug used mainly to control epileptic seizures. It is also used as an antimanic drug (in bipolar individuals), to prevent bipolar disorder, to ease alcohol withdrawal, or to relieve certain types of pain such as trigeminal neuralgia. Several conditions can affect blood levels and the efficacy of prescribed carbamazepine (intestinal absorption variations, liver disease, protein binding rates, combination with other medications, etc.). The carbamazepine test measures blood levels of the drug at least 10 hours after the last dose (unless otherwise specified by the physician), and results are expressed in micromoles per litre (µmol/L).
Most individuals respond with minimal side effects to a carbamazepine level between 30 and 50 µmol/L measured at least 10 hours after the last dose. In some individuals, this therapeutic zone will not adequately control seizures, mood swings or neuralgia, while others will experience excessive side effects even if the level remains within the zone. Side effects vary widely, from dizziness to drowsiness, loss of appetite, altered taste, constipation, nausea, dry mouth and throat, headache, memory loss, increased sensitivity to sunlight, ringing in the ears, etc.