The carbamazepine test is used to measure and monitor the amount of carbamazepine in the blood to determine whether the level of drug is within the therapeutic range. Carbamazepine is primarily used to treat certain seizure disorders (also called epilepsy) but is also prescribed to stabilize the moods of people with bipolar disease, to ease alcohol withdrawal, and to help alleviate some types of nerve pain.
Initially, the test may be used to establish the appropriate dose for an individual. Depending on the results of the blood test, the dose of drug may be adjusted up or down until the blood level reaches the therapeutic range. Subsequent tests are then used to ensure that the level remains in the therapeutic range. If a person’s health changes or if, for example, they begin taking other drugs, the test may be used to determine whether an adjustment to the prescribed dose is necessary.
The therapeutic range for carbamazepine when it is taken by itself is about 4 to 12 mcg/mL. Levels above 15 mcg/mL are considered toxic. Ranges vary slightly from laboratory to laboratory, however, and may be expressed in other units such as mg/L. Health practitioners and patients should use the therapeutic ranges and units established by the laboratory that performs the testing.
Within the therapeutic range, most people will respond to the drug without excessive side effects; however, response varies with each individual. Some people will experience seizures, mood swings, or nerve pain at the low end of the therapeutic range while some people will experience excessive side effects at the upper end. Variations in free carbamazepine and carbamazepine-10,11 epoxide can contribute to this response. People who use this medication should work closely with their healthcare provider to find the dosage that works the best for them.
- Sample of blood serum
- We perform the test daily