🧠 Psychosocial Integrity · Lesson 3 of 6 · 8 min

Lithium, SSRIs, MAOIs and the Emergencies They Cause

🧂 A client on lithium starts a new diuretic, goes on a low-salt diet, and trains for a half marathon in July. Each choice looks healthy. Together they are a toxicity case the exam loves to build.

💡 Key idea

Lithium 0.6 to 1.2 with steady salt and water. Serotonin syndrome: hot, hyperreflexic, agitated. MAOI plus tyramine: hypertensive crisis. NMS: fever and rigidity; stop the drug.

🧠 Why it matters

LITHIUM: therapeutic level 0.6 to 1.2 mEq/L; toxicity above about 1.5 shows as coarse tremor, nausea, vomiting, diarrhea, ataxia and confusion, and above 2.5 as seizures and arrhythmias. Keep sodium and fluid intake steady: sweating, dehydration, low-salt diets, NSAIDs and thiazide diuretics all raise lithium levels. SSRIs take 2 to 4 weeks to work; combining serotonergic drugs can cause SEROTONIN SYNDROME: agitation, hyperthermia, diaphoresis, hyperreflexia and clonus. Never stop SSRIs abruptly. MAOIs plus TYRAMINE-rich foods (aged cheese, cured meats, red wine, soy sauce, fermented foods) cause a HYPERTENSIVE CRISIS with severe headache. TRICYCLICS are anticholinergic and lethal in overdose, so limit the supply for at-risk clients. ANTIPSYCHOTICS cause extrapyramidal symptoms (acute dystonia, akathisia, pseudoparkinsonism, and tardive dyskinesia, which can be permanent) and NEUROLEPTIC MALIGNANT SYNDROME: high fever, lead-pipe muscle rigidity and autonomic instability; stop the drug and cool the client. CLOZAPINE causes agranulocytosis, so monitor the absolute neutrophil count and report sore throat or fever. BENZODIAZEPINES are never stopped abruptly because of withdrawal seizures.

🏥 In the real world

🌡️ Two days after a second antipsychotic is added, a client has a temperature of 40.2 °C, is rigid as a board and sweating with a blood pressure swinging between 180/100 and 90/60. This is neuroleptic malignant syndrome, not an infection. The nurse holds the antipsychotic, starts cooling measures and calls for the provider. Dantrolene and supportive care follow. A chart that said 'fever, started antibiotics' would have missed it.

📌 Takeaways

Lithium rises with dehydration, low sodium, NSAIDs and thiazides
SSRIs: 2 to 4 weeks to work; watch for serotonin syndrome
NMS: fever, rigidity, autonomic instability; clozapine: neutrophil counts

📖 Terms in this lesson

Serotonin syndrome: Agitation, fever, sweating, hyperreflexia and clonus from too much serotonergic medication.

Neuroleptic malignant syndrome (NMS): High fever, lead-pipe rigidity and unstable vital signs from antipsychotics; stop the drug and cool the client.

Tyramine: A substance in aged cheese, cured meats and red wine that causes a hypertensive crisis with MAOIs.

SSRIs and SNRIs: First-line antidepressants that take 4 to 6 weeks to work; watch for increased suicidal thinking in clients under 25 (boxed warning), serotonin syndrome when combined with other serotonergic drugs, sexual side effects and hyponatremia in older adults, and taper them to avoid discontinuation symptoms.

Tricyclic antidepressants: Older antidepressants, also used for nerve pain and bedwetting, that are lethal in overdose from cardiac arrhythmias, so prescriptions are kept small for anyone at risk of suicide; expect anticholinergic effects (dry mouth, constipation, urinary retention), sedation and orthostatic hypotension.

MAOIs (phenelzine, tranylcypromine, selegiline): Last-resort antidepressants that cause a hypertensive crisis (pounding headache, stiff neck, very high pressure) with tyramine foods such as aged cheese, cured meats and red wine, or with decongestants and other antidepressants; allow a 2-week washout before starting an SSRI (5 weeks after fluoxetine).

Bupropion: An antidepressant that also helps people quit smoking and spares sexual function; it lowers the seizure threshold, so it is contraindicated in seizure disorders, eating disorders and abrupt alcohol or benzodiazepine withdrawal, and it can cause insomnia and agitation.

Lithium: The bipolar mood stabilizer with a narrow range (0.6 to 1.2 mEq/L); toxicity above about 1.5 brings coarse tremor, vomiting, diarrhea and ataxia, so keep salt and fluid intake steady, avoid NSAIDs, thiazides and ACE inhibitors, and check kidney and thyroid function.

Buspirone: A non-sedating anxiety drug with no dependence or abuse potential but no use as a rescue dose for panic; it takes 2 to 4 weeks to work, must be taken every day, causes dizziness, and should not be combined with MAOIs or grapefruit juice.

Methylphenidate and amphetamine stimulants: First-line ADHD drugs and controlled substances with abuse potential; expect appetite loss, insomnia and weight loss, so give the last dose early in the day and track height and weight in children, check heart rate and blood pressure, and watch for tics and mood changes.

✅ Test yourself

A client on lithium reports vomiting, diarrhea, coarse hand tremors and feeling unsteady. The lithium level is 1.9 mEq/L. What should the nurse do first?

Give the next scheduled dose and recheck the level tomorrow
Hold the lithium and notify the provider
Encourage a low-sodium diet
Administer an NSAID for discomfort

Answer: B · Hold the lithium and notify the provider

These are signs of lithium toxicity above the therapeutic range. Hold the drug, notify the provider and prepare for IV fluids and monitoring; low sodium and NSAIDs would raise the level further.

A client taking an MAOI should be taught to avoid which food?

Freshly cooked white rice
Fresh grilled chicken breast
Fresh apples and pears
Aged cheddar cheese

Answer: D · Aged cheddar cheese

Aged cheeses are high in tyramine, which with an MAOI can trigger a hypertensive crisis.

A client taking clozapine reports a sore throat and fever. What is the priority concern?

Lithium toxicity
Tardive dyskinesia
Serotonin syndrome
Agranulocytosis

Answer: D · Agranulocytosis

Clozapine can suppress neutrophils; infection signs require an immediate white count and holding the drug if the count is low.

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