Antidote:: MDAC, +/- haemodialysis - structurally related to [[TCA overdose|TCAs]] and phenytoin ; similar pattern of toxicity - [[Sodium channel blocker|Na-channel blocker]] - [[Anticholinergic toxicity|antimuscarinic]] actions **Risk assessment** - peak plasma concentrations after 8-12 hours for toxic ingestions of immediate release formulations ; 24-96 hours of slow release formulations in massive OD - small Vd 1L/kg - therapeutic range 20-50 micromol/L - moderate tox is 80-160 micromol/L - profound ↓ GCS - frequent dystoic reactions - tachycardia - severe tox > 180 micromol/L - [[Seizures#Toxicological Seizures]] - GCS 3 - hypotension and myocardial depression common - QRS widening, [[Long QT|QTc]] prolongation, arrhythmias - **children** - toxicity at levels 30% lower than adults due to ↑ active metabolite production - higher incidence of dystonia, choreoathetosis and seizures - lower incidence of cardiotoxicity | severity | dose ingested <br>mg/kg | concentration <br>umol/L (mg/L) | | --------- | ----------------------- | ------------------------------- | | mild/none | <20 | ≤ 85 ( ≤20) | | moderate | 20-50 | 85-170 (20 - 40) | | severe | >50 | >170 (>40) | **Management** - decontamination -- [[Decontamination#Dose for MDAC|MDAC]] in significant toxicity - hypotension -- IVF - [[HCO3 therapy|NaHCO3]] if: - fluid-resistant - QRS widening - significant arrhythmias - add adrenaline or noradrenaline if fluid resistant - seizures -- benzos - [[haemodialysis]] - severe toxicity resistant to non-invasive therapy - *haemofiltration* is method of choice in severe toxicity as it also removes protein bound drug - *haemodialysis* effective in removing CVZ-E - charcoal haemoperfusion decreases toxic levels by 20%, however this is the same as MDAC. # Related Questions ## carbamazepine - [ ] 1Q: [Overdose](x-devonthink-item://80040649-2DDB-4266-9A7C-4DE4E6DD4AE6?page=14) -- [Answer](x-devonthink-item://C96EDD2F-137A-43E5-80EE-5F42C5971D55?page=19)