Drug reference

obidoxime

Cholinesterase reactivator (oxime; organophosphate antidote) · Antidote (for organophosphate poisoning)

START

250 mg IV slow load, then 750 mg/24 h infusion (with atropine)

TYPICAL MAX

~5 g/day (severe poisoning, monitored)

STOP IF

Significant hepatotoxicity, severe hypertension, or AV block

WATCH

Cholinergic response, BP/ECG, LFTs (>24 h use), atropine titration

CDSCO approvedATC V03AB13

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 6min · IV onset
PEAK: 30min · post-bolus
t½: 2h · t½
DURATION: 7h · per dose

EXCRETION

Renal — largely unchanged

route + CYP

INTERACTIONS

1 major

SEVERE in our sources

PREGNANCY

Use in life-threatening OP poisoning — benefit outweighs risk.

FDA category + note

Top interactionssee all 5 →

Carbamate InsecticidesSevereDatabaseKimi deep-research + Cla

Mechanism

Bisquaternary oxime that reactivates organophosphate-inhibited acetylcholinesterase by removing the phosphoryl group from the enzyme's active site, restoring cholinergic function; effective before 'aging' of the OP-enzyme bond.

Indications

Acute organophosphate (pesticide / nerve-agent) poisoning (with atropine and supportive care)

Dosing

Adult: Loading: 250 mg IV slowly, followed by 750 mg/24 h continuous infusion (or repeat 250 mg every 2 h as needed for ~24 h); combined with atropine titrated to effect.
Pediatric: 4–8 mg/kg IV slowly, repeat as needed.
Renal adjustment: Reduce dose in severe impairment (renally excreted).
Hepatic adjustment: Caution / reduce in significant hepatic disease (hepatotoxicity risk).
Geriatric: Standard emergency use; monitor.
Max dose: Up to ~5 g/day (severe poisoning, monitored)

Pharmacokinetics

Onset

Within minutes (IV)

Peak effect

End of bolus / steady-state infusion

Duration

~6–8 h

Half-life

~1.4–2.7 h

Bioavailability

IV/IM (not oral)

Protein binding

Low

Metabolism

Minimal

Excretion

Renal (largely unchanged)

Contraindications

Hypersensitivity
Caution: severe hepatic impairment, carbamate poisoning (oxime contraindicated in pure carbamate)

Side effects

Common

DizzinessNauseaTachycardiaHot flushesHeadache

Serious

Severe hepatotoxicity (high dose, sustained)
Hypertension (rapid IV)
Atrioventricular block
Worsened weakness if used in pure carbamate poisoning

Pregnancy & lactation

Pregnancy

Use in life-threatening OP poisoning — benefit outweighs risk.

Lactation

Limited data; brief use acceptable in emergency.

Drug interactions

Carbamate Insecticides

Severe

Database

Oxime contraindicated in pure carbamate (worsens weakness)

Identify agent; avoid in pure carbamate