Psychiatric medications nursing reference: antipsychotics and mood stabilizers

Psychiatric medications are among the highest-yield pharmacology topics on NCLEX — and among the most difficult to organize in memory. Nursing students encounter antipsychotics and mood stabilizers across inpatient psychiatric units, med-surg floors, emergency departments, and community health settings. These drugs have narrow therapeutic windows, serious adverse effect profiles, and monitoring requirements that nurses must know before administration, not after.

This reference covers two major classes: antipsychotics (typical and atypical) and mood stabilizers (lithium, valproate, lamotrigine, carbamazepine). For each drug, you’ll find mechanism of action, key side effects, nursing monitoring priorities, and the specific NCLEX facts that appear on the exam. Use it alongside the schizophrenia nursing reference and bipolar disorder nursing guide for integrated clinical and pharmacological coverage.

Fast-scan: drug class overview

Antipsychotic medications: typical vs atypical

Antipsychotics are the cornerstone pharmacological treatment for schizophrenia, acute mania, and psychotic symptoms across multiple diagnoses. The distinction between typical (first-generation) and atypical (second-generation) agents is clinically and conceptually important — they differ in mechanism, side effect burden, and clinical application.

Typical (first-generation) antipsychotics

First-generation antipsychotics (FGAs) work by blocking D2 dopamine receptors in the mesolimbic pathway, reducing the excess dopaminergic activity responsible for positive symptoms — hallucinations, delusions, and disorganized thought. Effectiveness requires blockade of approximately 72% of D2 receptors. FGAs are highly effective against positive symptoms but provide little benefit for negative symptoms (flat affect, avolition, social withdrawal).

Key agents:

• Haloperidol (Haldol) — high-potency FGA; less sedating, more EPS risk; available in oral, IM, and long-acting injectable (LAI) formulations; first-line for acute agitation in many inpatient settings
• Chlorpromazine (Thorazine) — low-potency FGA; more sedating, more anticholinergic effects; historically significant as the first antipsychotic developed

Side effects of typical antipsychotics:

Extrapyramidal symptoms (EPS) — result from D2 blockade in the nigrostriatal dopamine pathway:

• Acute dystonia — involuntary sustained muscle contractions; often affects neck (torticollis), jaw, tongue, eyes (oculogyric crisis); onset within hours to days of starting or dose increase; treat with IM benztropine (Cogentin) or IM diphenhydramine (Benadryl)
• Parkinsonism — drug-induced bradykinesia, rigidity, resting tremor, shuffling gait; onset within days to weeks; managed with dose reduction or benztropine
• Akathisia — subjective restlessness, compulsion to move; often described as inability to sit still; onset within days to weeks; managed with dose reduction, propranolol, or lorazepam; commonly mistaken for anxiety — an important clinical distinction
• Tardive dyskinesia (TD) — late-onset involuntary repetitive movements of the face, tongue, or limbs (lip smacking, tongue protrusion, choreoathetoid movements); associated with long-term high-potency FGA use; may be irreversible; AIMS screening scale used for monitoring; reducing or stopping the antipsychotic may worsen TD initially

Neuroleptic malignant syndrome (NMS) — a rare but life-threatening emergency. Onset typically within 24–72 hours of initiation or dose increase. The clinical tetrad is: hyperthermia, severe muscle rigidity (“lead pipe” rigidity), altered consciousness, and autonomic instability (diaphoresis, tachycardia, labile BP). Labs show elevated CPK, leukocytosis, elevated liver enzymes, and myoglobinuria leading to acute renal failure. Management: immediately discontinue the antipsychotic, provide aggressive supportive care, administer dantrolene 0.8–2.5 mg/kg IV every 6 hours (up to 10 mg/kg/day), and consider bromocriptine.

Anticholinergic effects — dry mouth, urinary retention, constipation, blurred vision, confusion (especially in older adults).

Orthostatic hypotension — monitor BP lying and standing; instruct patients to rise slowly.

Sedation — varies by potency; low-potency FGAs (chlorpromazine) are more sedating than high-potency (haloperidol).

Atypical (second-generation) antipsychotics

Second-generation antipsychotics (SGAs) block both D2 dopamine receptors and 5-HT2A serotonin receptors. The serotonin antagonism modulates dopamine release in the nigrostriatal pathway, reducing EPS risk compared to FGAs. SGAs address both positive and negative symptoms — a significant clinical advantage.

Key agents and distinguishing features:

• Clozapine (Clozaril) — the most effective antipsychotic for treatment-resistant schizophrenia; reserved for patients who have failed two or more adequate antipsychotic trials; carries agranulocytosis risk requiring mandatory CBC monitoring under the FDA REMS program (see below)
• Risperidone (Risperdal) — effective for positive and negative symptoms; highest EPS risk among SGAs at higher doses; available as LAI (Risperdal Consta); prolactin elevation common
• Olanzapine (Zyprexa) — most associated with weight gain and metabolic syndrome; significant sedation; effective for both schizophrenia and bipolar mania
• Quetiapine (Seroquel) — lowest EPS risk of all SGAs; significant sedation and orthostatic hypotension; used for bipolar depression and as adjunct for MDD; metabolic monitoring required
• Aripiprazole (Abilify) — partial D2 agonist (unique mechanism — activates underdopaminergic pathways while blocking overdopaminergic ones); most likely to cause akathisia among SGAs; least associated with weight gain and metabolic effects; useful in patients where metabolic risk is a concern

Side effects of atypical antipsychotics:

Metabolic syndrome — the most clinically significant long-term risk. Weight gain, elevated fasting glucose, insulin resistance, dyslipidemia, and elevated blood pressure. Olanzapine and clozapine carry the highest metabolic risk; aripiprazole and ziprasidone the lowest. Monitor fasting glucose, lipid panel, waist circumference, and BMI at baseline and periodically.

Sedation — common with clozapine, olanzapine, quetiapine; less common with aripiprazole.

Orthostatic hypotension — clozapine and quetiapine carry the highest risk; educate patients to rise slowly.

QTc prolongation — ziprasidone requires baseline and periodic ECG monitoring; avoid combining with other QTc-prolonging agents.

Hyperprolactinemia — more common with risperidone; causes galactorrhea, amenorrhea, sexual dysfunction, and long-term bone density concerns.

Clozapine special considerations — the REMS program:

Clozapine is the only antipsychotic that requires mandatory enrollment in the FDA Risk Evaluation and Mitigation Strategy (REMS) program due to agranulocytosis risk (estimated 1–2% of patients). The absolute neutrophil count (ANC) must be monitored:

• Weekly for the first 6 months
• Every 2 weeks for months 7–12
• Monthly thereafter if ANC remains stable

Hold clozapine and notify the provider if ANC falls below 1,000 cells/mm³ (or below 500 cells/mm³ in patients with benign ethnic neutropenia). Clozapine also carries risks for seizures (dose-dependent), myocarditis (first month of treatment), constipation severe enough to cause bowel obstruction, and severe orthostatic hypotension. Despite its risk profile, clozapine significantly reduces suicide risk in schizophrenia — it is FDA-approved for suicidality in schizophrenia and schizoaffective disorder.

Mood stabilizers

Mood stabilizers treat and prevent the mood episodes of bipolar disorder — mania, hypomania, and depression. The four agents most relevant to nursing and NCLEX are lithium, valproate/divalproex, lamotrigine, and carbamazepine.

Lithium

Lithium remains the gold-standard mood stabilizer for bipolar disorder. Its mechanism is not fully understood, but it is thought to modulate second messenger systems (particularly inositol signaling) and compete with sodium, potassium, calcium, and magnesium ions in neural transmission. Lithium reduces both manic and depressive episodes and is the only psychiatric medication with robust evidence for suicide risk reduction.

Therapeutic range: 0.6–1.2 mEq/L (maintenance). Acute mania may require 1.0–1.5 mEq/L. Draw levels 8–12 hours after the last dose.

Toxicity thresholds:

• Early/mild toxicity (1.5–2.0 mEq/L): Fine hand tremor (coarse tremor is a red flag), GI symptoms (nausea, vomiting, diarrhea), polyuria, fatigue, muscle weakness
• Moderate toxicity (2.0–2.5 mEq/L): Coarse tremor, confusion, ataxia, slurred speech, hypotension, bradycardia, ECG changes
• Severe toxicity (>2.5 mEq/L): Seizures, renal failure, coma, cardiac arrhythmias — potentially fatal. Treatment is hemodialysis.

Key nursing monitoring — lithium:

Sodium intake directly affects lithium levels. Low-sodium states (dehydration, low-salt diet, vomiting, diarrhea, excessive sweating, loop diuretics) reduce renal lithium clearance, causing levels to rise and toxicity to develop. Instruct patients to maintain consistent sodium intake, drink 8–12 glasses of water daily, and avoid NSAIDs (reduce renal clearance) and thiazide diuretics.

Obtain baseline and monitor: serum lithium level, BMP (creatinine, electrolytes), thyroid function (TSH, T3, T4) — lithium causes hypothyroidism in 20–40% of patients — and urinalysis. Lithium causes nephrogenic diabetes insipidus in 20–40% of patients (polyuria, polydipsia).

Valproate (divalproex/valproic acid)

Valproate (brand names Depakote, Depakene) works by enhancing GABA inhibitory neurotransmission and stabilizing sodium channels, reducing neuronal excitability. It is FDA-approved for acute mania in bipolar disorder, complex partial and absence seizures, and migraine prophylaxis.

Monitoring: Therapeutic serum level for bipolar: 50–125 mcg/mL. Monitor liver function tests (LFTs) — valproate carries a black box warning for fatal hepatotoxicity, most commonly in children under 2 on polytherapy. Monitor CBC (thrombocytopenia), ammonia levels (valproate-induced hyperammonemic encephalopathy — confusion without elevated LFTs), and lipase (pancreatitis risk).

Side effects: Weight gain, GI distress (give with food), alopecia, tremor, sedation, teratogenicity (neural tube defects — absolute contraindication in pregnancy if avoidable; requires folic acid supplementation).

Lamotrigine

Lamotrigine (Lamictal) works by inhibiting glutamate release and enhancing GABA transmission, stabilizing neuronal firing. It is particularly effective for bipolar depression and is a preferred maintenance agent for bipolar II disorder.

Critical risk — Stevens-Johnson syndrome (SJS): Lamotrigine carries a black box warning for life-threatening skin reactions, including SJS and toxic epidermal necrolysis (TEN). Risk is highest during initial titration, particularly if the dose is increased too rapidly. The standard protocol requires slow titration over 6–8 weeks (dose doubled no faster than every 2 weeks). Risk is further increased when lamotrigine is co-administered with valproate (which inhibits lamotrigine metabolism, doubling its half-life).

Nursing priority: Educate patients to report any new rash, blistering, mucosal involvement, or flu-like symptoms immediately. Any rash during the first 8 weeks of therapy should be evaluated urgently and may require drug discontinuation.

Carbamazepine

Carbamazepine (Tegretol) stabilizes sodium channels, reducing repetitive neuronal firing. It is used for bipolar disorder (particularly mixed episodes and rapid cycling), seizures, and trigeminal neuralgia.

Monitoring: Therapeutic level for bipolar: 4–12 mcg/mL. Monitor CBC — carbamazepine carries a black box warning for aplastic anemia and agranulocytosis (less common than with clozapine but clinically significant). Also monitor LFTs, electrolytes (hyponatremia/SIADH risk), and serum levels.

Drug interactions: Carbamazepine is a potent inducer of CYP3A4 and can reduce the plasma levels of many medications, including oral contraceptives (counsel on alternative contraception), warfarin, other anticonvulsants, and some antipsychotics. It also induces its own metabolism (autoinduction), meaning dose adjustments may be needed in the first few weeks.

Side effects: GI upset, dizziness, diplopia, ataxia (dose-related), hyponatremia, rash. Instruct patients to take with food. Avoid grapefruit juice (CYP3A4 inhibitor — increases carbamazepine levels).

Nursing considerations and monitoring

The table below summarizes key monitoring requirements by drug — the before, during, and after framework nurses use in clinical practice.

NCLEX high-yield points

NCLEX pharmacology questions on psychiatric medications test the same concepts repeatedly. Knowing these cold is the difference between a correct answer and a distractor:

Lithium toxicity — the numbers that always appear:

• Therapeutic range: 0.6–1.2 mEq/L
• Mild toxicity begins at: 1.5 mEq/L
• Severe/potentially fatal: >2.5 mEq/L
• Early toxicity signs: fine tremor, GI symptoms, polyuria — often described in a vignette as a patient who “has diarrhea and is acting confused”
• Always draw lithium levels 8–12 hours after the last dose

Clozapine — the monitoring question:

• ANC must be checked weekly for the first 6 months, then every 2 weeks for months 7–12
• Hold clozapine if ANC falls below 1,000 cells/mm³
• REMS enrollment is mandatory — pharmacies cannot dispense without confirmed monitoring

EPS management — which drug for which symptom:

• Acute dystonia and parkinsonism: benztropine (Cogentin) or diphenhydramine (Benadryl)
• Akathisia: propranolol (beta-blocker) or benzodiazepine; benztropine is less effective
• Tardive dyskinesia: reduce or discontinue antipsychotic; valbenazine (Ingrezza) or deutetrabenazine (Austedo) are FDA-approved treatments

NMS vs serotonin syndrome — distinguish them: NCLEX frequently tests the ability to differentiate these two conditions (see detailed comparison in the next section).

Lamotrigine and rash:

• Report any rash during the first 8 weeks of therapy
• Risk increases dramatically when combined with valproate — start at half the usual dose

Sodium and lithium:

• Low-sodium states cause lithium toxicity — patients with vomiting, diarrhea, heavy sweating, or on low-salt diets need level monitoring
• NSAIDs and thiazide diuretics increase lithium levels — loop diuretics are safer if a diuretic is needed

Common confusions: NMS vs serotonin syndrome vs EPS

These three drug-induced syndromes are high-yield for NCLEX and often confused in clinical practice. The distinctions matter because management is different — and delay can be fatal for NMS and serotonin syndrome.

The clinical shortcut: NMS = “lead pipe” rigidity + high fever + antipsychotic exposure. Serotonin syndrome = clonus + hyperreflexia + serotonergic drug exposure + rapid onset. Both require stopping the offending drug immediately.

Lithium levels — therapeutic vs toxic vs lethal:

Related pages in the psychiatric nursing series

This article is the pharmacological companion to the full psychiatric nursing reference series. Each condition page links to relevant medications:

• Schizophrenia nursing reference — positive/negative symptoms, EPS, clozapine protocol, NMS assessment
• Bipolar disorder nursing guide — DSM-5 criteria, mood episode assessment, lithium monitoring protocol, therapeutic communication
• Anxiety disorders nursing reference — GAD, panic disorder, PTSD, OCD; SSRIs, benzodiazepines, buspirone
• Depression nursing reference — MDD criteria, antidepressant pharmacology, suicide risk assessment
• Substance use disorders nursing reference — CIWA-Ar, COWS, medication-assisted treatment, withdrawal management
• Eating disorders nursing reference — anorexia, bulimia, BED, refeeding syndrome protocol
• Personality disorders nursing reference — all 10 DSM-5 disorders, BPD dialectical behavior therapy, therapeutic communication strategies