Antipsychotic toxicity: Difference between revisions
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*Toxicity results in blockade of some or all of the following receptors: | *Toxicity results in blockade of some or all of the following receptors: | ||
**Dopamine - extrapyramidal symptoms | **Dopamine - extrapyramidal symptoms | ||
** | **α-1 - orthostatic hypotension, reflex tachycardia | ||
**Muscarinic - anticholinergic symptoms | **Muscarinic - anticholinergic symptoms | ||
**Histamine - sedation | **Histamine - sedation | ||
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*CNS | *CNS | ||
**Lethargy, ataxia, dyarthria, confusion, coma | **Lethargy, ataxia, dyarthria, confusion, coma | ||
**Seizure (1%) | **[[Seizure]] (1%) | ||
*Anticholinergic Effects | *Anticholinergic Effects | ||
**Tachycardia, dry mucous membranes, dry skin, decreased bowel sounds, delirium | **Tachycardia, dry mucous membranes, dry skin, decreased bowel sounds, delirium | ||
| Line 46: | Line 46: | ||
===Extrapyramidal=== | ===Extrapyramidal=== | ||
*[[Diphenhydramine]] 25-50mg IV/IM OR [[benztropine]] 1-2mg IV/IM | *[[Diphenhydramine]] 25-50mg IV/IM '''OR''' [[benztropine]] 1-2mg IV/IM | ||
*Oral therapy with either of above meds should be continued for 2 weeks | *Oral therapy with either of above meds should be continued for 2 weeks | ||
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==See Also== | ==See Also== | ||
*[[Antipsychotics]] | |||
*[[Toxicology (main)]] | |||
*[[Neuroleptic Malignant Syndrome (NMS)]] | *[[Neuroleptic Malignant Syndrome (NMS)]] | ||
*[[Tardive_dyskinesia|Tardive dyskinesia]] | *[[Tardive_dyskinesia|Tardive dyskinesia]] | ||
Latest revision as of 04:05, 7 March 2021
Background
- Isolated overdose of antipsychotics is rarely fatal
- Toxicity results in blockade of some or all of the following receptors:
- Dopamine - extrapyramidal symptoms
- α-1 - orthostatic hypotension, reflex tachycardia
- Muscarinic - anticholinergic symptoms
- Histamine - sedation
Clinical Features
- Extrapyramidal
- Acute dystonic reaction
- Tongue protrusion, facial grimacing, trismus, oculogyric crisis
- Akathisia
- Acute dystonic reaction
- CNS
- Lethargy, ataxia, dyarthria, confusion, coma
- Seizure (1%)
- Anticholinergic Effects
- Tachycardia, dry mucous membranes, dry skin, decreased bowel sounds, delirium
- ECG changes
- Sinus tachycardia
- QT prolongation
Differential Diagnosis
Anticholinergic toxicity Causes
- Medications[1]
- Atropine
- Antihistamines
- Antidepressants
- Antipsychotics
- Muscle relaxants
- Anti-Parkinsonians
- Plants
- Jimson weed (Devil's trumpet)
- Amanita mushroom
Evaluation
Workup
- POC Glucose
- ECG (QT interval)
- Co-ingestions: serum acetaminophen, salicylate, EtOH level, other known drug levels
- Urine toxicology screen
- Chemistry (metabolic acidosis, electrolytes, renal function)
- LFT (hepatotoxicity)
- CK (rhabdomyolysis)
- Serum osmolarity (osmolar gap)
- ABG (carboxyhemoglobin, methemoglobin)
Management
Supportive
- Hypotension
- QT prolongation
- Treat all with QTc >500ms with magnesium 2-4gm IV over 10min
Extrapyramidal
- Diphenhydramine 25-50mg IV/IM OR benztropine 1-2mg IV/IM
- Oral therapy with either of above meds should be continued for 2 weeks
Disposition
- Consider discharge after 6hr as long as there are all of the following:
- No mental status changes
- Normal HR/BP
- No orthostatic hypotension
- Normal QT interval
See Also
- Antipsychotics
- Toxicology (main)
- Neuroleptic Malignant Syndrome (NMS)
- Tardive dyskinesia
- Beta-Blocker Toxicity
- Calcium Channel Blocker Toxicity
- Extrapyramidal reaction
External Links
References
- ↑ Dawson AH, Buckley NA. Pharmacological management of anticholinergic delirium – theory, evidence and practice. Br J Clin Pharmacol. 2015;81(3):516-24.