Stage 3: Mood Stabilizers
Concept 8 of 8
R3.8

Mood Stabilizer Monitoring

Labs, levels, and surveillance — the practical infrastructure that makes mood stabilizers safe.

Lithium: baseline and annual renal function (BUN/Cr, GFR), thyroid (TSH), electrolytes, pregnancy test. Lithium level 5-7 days after dose change; every 3-6 months at steady state. Trough levels (~12 hours post-dose).

Mood stabilizer monitoring is the infrastructure that makes long-term safe use possible. Each agent has its own monitoring schedule, and skipping the labs is one of the most common ways psychiatric prescribing produces preventable adverse outcomes years later.

Drug card
Class
Monitoring infrastructure
Mechanism
Drug-specific monitoring intervals, serum levels, organ function surveillance
FDA indications
Required laboratory infrastructure for each agent — lithium, valproate, carbamazepine, lamotrigine, antipsychotics used for bipolar

Monitoring is the difference between safe mood stabilizer use and preventable adverse events. Practical workflow: baseline → titration period (more frequent) → steady state (every 3-6 months for most).

Lithium: baseline renal function (BUN, creatinine, eGFR), thyroid function (TSH), electrolytes, pregnancy test in women of childbearing potential, ECG in patients over 50 or with cardiac risk. Annual repeat of renal and thyroid. Lithium level 5-7 days after each dose change, every 3-6 months at steady state, drawn as a trough roughly 12 hours after the last dose. The long-term concerns are chronic kidney disease (incidence rises with duration) and hypothyroidism (15-30% over years).

Mechanism in practice

Mood stabilizer monitoring is mechanism-driven — each agent's organ effects dictate a specific surveillance schedule that makes long-term treatment safe.

Mechanism
Lithium: narrow therapeutic index, renal/thyroid effects
Effect
Toxicity risk; hypothyroidism, renal decline, hyperparathyroidism
Clinical applications
Serum level (target by indication), creatinine/eGFR, TSH, calcium — baseline and periodically (every 3-6 months once stable).
Mechanism
Valproate: hepatic, hematologic, pancreatic, metabolic effects
Effect
Hepatotoxicity, thrombocytopenia, pancreatitis, weight gain
Clinical applications
Level, LFTs, CBC, plus weight and metabolic monitoring; ammonia level if confusion develops.
Mechanism
Carbamazepine: marrow, hepatic, sodium effects; autoinduction
Effect
Agranulocytosis, hepatotoxicity, hyponatremia; self-lowering levels
Clinical applications
CBC, LFTs, sodium, level — including a re-check after autoinduction (~3-5 weeks).
Mechanism
SGAs: metabolic effects
Effect
Weight gain, dyslipidemia, glucose dysregulation
Clinical applications
Weight/BMI, waist, fasting glucose or A1c, lipid panel — baseline and at defined intervals.

Mechanism note: Monitoring is not bureaucratic — each schedule is dictated by the agent's specific organ effects. The monitoring discipline is what converts effective but hazardous agents into safe long-term treatment.

Valproate: baseline LFTs, CBC with platelets, pregnancy test. Periodic LFTs and CBC. Valproate level periodically. Hyperammonemia check if mental status changes — ammonia level can rise on valproate without obvious cause and produce confusion. PCOS features in long-term female patients.

Carbamazepine: baseline CBC (aplastic anemia risk), LFTs, sodium, carbamazepine level, HLA-B*1502 in patients of Asian ancestry. Periodic repeat. Sodium especially with oxcarbazepine due to SIADH risk.

Valproate: LFTs (q3-6mo), CBC with platelets, valproate level, pregnancy test. Carbamazepine: CBC (aplastic anemia risk), LFTs, sodium, carbamazepine level, HLA-B*1502 baseline.

Lamotrigine: no specific lab monitoring needed routinely. Clinical monitoring for rash during titration is the priority.

Atypical antipsychotics used for bipolar: metabolic monitoring is the central framework. Weight every visit. Blood pressure quarterly. Fasting glucose and A1c annually, sooner if weight rising rapidly or symptoms emerging. Lipid panel annually. Prolactin only if symptoms (galactorrhea, menstrual changes, sexual dysfunction). AIMS exam annually for tardive dyskinesia screening.

Atypical antipsychotics for bipolar: weight (every visit), BP (q3mo), fasting glucose/A1c (annual or sooner), lipid panel (annual), prolactin if symptoms, AIMS exam annually.

The monitoring framework feels like extra work until it isn't. The patient whose lithium level drifts to 1.8 because of a new ACE inhibitor and was caught at three-month routine labs avoided a hospitalization. The patient whose new diabetes on quetiapine was caught at annual A1c got metformin and weight management early rather than late. Every monitoring visit is a small intervention against the much larger interventions you'd otherwise eventually do.

The anchor

Mood stabilizer safety depends on systematic monitoring — drug-specific labs, intervals, and patient education form the practical infrastructure that makes these medications usable long-term.

Prove it

A patient has been on lithium 900 mg for 3 years with stable mood. The patient asks why they need ongoing labs. What is your response?

This connects to

Locked concepts unlock as you reach them on the path.

Back