---
title: "Mood Stabilizer Tips"
url: https://mghmclean.org/residents/handbk/part2c/gaba.htm
description: "· Lab work is required for lithium, valproic acid, carbamazapine"
published: 2026-08-10
updated: 2026-08-10
---

# Mood Stabilizer Tips

Published 2026-08-10

PART 3 / CH 54

Marion Eakin and George Papakostas

Checking blood levels

· Lab work is required for lithium, valproic acid, carbamazapine

· Levels of lithium, valproic acid, carbamazapine should be drawn at *trough*, i.e. ~ 11-12 hours post last dose and prior to next dose.

· Have patients delay their a.m. dose until after blood is drawn.

· After a dose change, allow 3-5 days to reach steady state (depends on t ½)

Drug interactions and toxicity

· Carbamazapine has many drug-drug interactions, check PDR before prescribing

· Avoid combination of carbamazapine + clozapine (Clozaril): increased risk of agranulocytosis

· 1-3/1000 patients develop a potentially life-threatening rash on lamotrigine (Stevens-Johnson, toxic epidermal necrolysis etc.)

· Valproic acid will increase level and half-life of lamotrigine by 2, increasing risk of life-threatening rash associated with lamotrigine.

## Lamotrigine and Gabapentin

Marion Eakin and George Papakostas

|  | Gabapentin | Lamotrigine |
|---|---|---|
| Start | 300QD | 25 QD; titrate slowly |
| Clearance | Renal (unaltered) | Hepatic>renal (unaltered) |
| Side effects | Somnolence, ataxia, fatigue, dizziness, nystagmus | RASH! Dizziness, ataxia, sedation, nause, visual blurring, headache |
| Toxicity | Diarrhea, lethargy, ataxia, labored breathing, diplopia | Dizziness, headache, somnolence, coma |
| Labs | None required | None required; lytes/BUN/Cr and LFT in older patients |
| Target | N/A | N/A |
| Teratogen | + | ? |