Benztropine is used in acute dystonic reactions, it blocks striatal cholinergic receptors, thus helping to balance the cholinergic and dopaminergic activity. Drugs responsible for dystonic reactions other than antipsychotics include:
- Antiemetics — e.g. metaclopramide, proclorperazine
- Antidepressants and serotonin receptor agonists — e.g. SSRIs, buspirone, sumitriptan
- Antibiotics — e.g. erythromycin
- Antimalarials — e.g. chloroquine
- Anticonvulsants — e.g. carbamazepine, vigabatrin
- H2 receptor antagonists — e.g. ranitadine, cimetidine
- Recreational drugs — e.g. cocaine
- ABCDE – patient may have laryngospasm.
- First line treatment of acute dystonic reactions
- Response is often dramatic and generally occurs in 5-20mins
- if symptoms persist after 15-30mins a second dose can be given.
- if symptoms persist and are not improving after second dose consider the possibility of an alternative diagnosis.
- Adult: 1-2mg by slow IV injection – if IV is not possible it can be given IM but may take 30 minutes to work.
- Child: 0.02mg/kg to maximum of 1mg
- Campbell, D. (2001). The management of acute dystonic reactions. Australian Prescriber. 24(1), 19-20.
- Fines, R. Brady, W. & DeBehnke. (1997). Cocaine-Associated Dystonic Reaction. American Journal of Emergency Medicine. 15(5), 513-516. PMID: 9270394
- Khan, N. & Razzak, J. (2006). Abdominal pain with rigidity secondary to the anti-emetic drug metaclopramide. The Journal of Emergency Medicine. 30(4), 411-413. PMID: 16740451
- Nochimson, G. (2009). Toxicity, Medication-Induced Dystonic Reactions. http://emedicine.medscape.com/article/814632-overview
- Yis, U. et.al. (2005). Metaclopramide induced dystonia in children: two case reports. European Journal of Emergency Medicine. 12, 117-119. PMID: 15891443