Understanding Blood Levels for Lamotrigine: A Guide for Patients with Bipolar Disorder

I've been taking Lamotrigine (Lamictal) for years now and have never had bloodwork done to check levels. However, as we learn more about its role in psychiatry, blood levels might become more clinically important.

Current Practices and Recommendations

Because there is no established therapeutic level for psychiatric efficacy, and dosage ranges vary based on efficacy and side effects, Lamotrigine levels are not typically checked. My wife has been on Lamictal for years and had her level drawn only once. As we learn more about its role in psychiatry, blood levels may become more relevant.

I have Bipolar II, and Irsquo;m on Lithium and Lamictal. You donrsquo;t check Lamictal levels, and there is no test for that. You do test Lithium levels and Valproic acid (Depakote),aiming for a 0.7 to 0.8 range for Lithium, and a 50 to 100 microgram/mL range for Depakote. Lithium and Lamictal saved my life, literally.

Trough Levels and the Steady State

Once a medication is ingested for a while, the blood level of the medication reaches a steady state. At this point, you can measure a ldquo;trough levelrdquo;, which is drawn approximately 12 hours after the last dose.

For Lithium, the usual trough level is between 0.8 to 1.2 acutely, meaning if your mood is actively cycling. Once yoursquo;re stable, I have seen people with a trough level of 0.6 doing fairly well. Nowadays, when I draw Lithium levels, I just ensure the level is not too high, but otherwise clinical observation and dose adjustments based on symptoms are more relevant than the trough level.

Depakote and Tegretol

For Depakote (Valproic acid), the lab will indicate a normal range of 50 to 100 microgram/mL. However, in psychiatry, this range is not as useful. In Neurology, you aim for this range to prevent future seizures since Depakote is an anticonvulsant. If the level gets to 120 or 150 microgram/mL, there is a risk of Depakote toxicity, including ataxia (loss of balance and coordination).

Tegretol (Carbamazepine) is a unique medication as it induces its own metabolism over time through the liver. If yoursquo;ve been on Tegretol for years, it may be eliminated faster, requiring you to monitor levels and increase the dose to compensate.

Conclusion and Advice

We never get Lamotrigine levels in psychiatry. Titration is based on clinical efficacy, and blood levels are typically not checked. If you have specific concerns, seek advice from your physician. Only your physician can make the appropriate diagnosis and come up with your treatment plan.