PROTOPAM CHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PROTOPAM CHLORIDE (PROTOPAM CHLORIDE).
Reactivates acetylcholinesterase inhibited by organophosphate poisoning by binding to the organophosphate moiety, forming a complex that undergoes hydrolysis to regenerate active enzyme. Also has a direct neutralization effect on certain organophosphates.
| Metabolism | Hepatic metabolism (minor); primarily excreted unchanged in urine. |
| Excretion | Renal excretion is the primary route, with 80-90% of a dose eliminated unchanged in urine within 30 minutes; the remainder is metabolized and excreted fecally. |
| Half-life | Terminal elimination half-life is approximately 1.7 hours in adults. In renal impairment, half-life may be prolonged up to 6 hours, requiring dose adjustment. |
| Protein binding | Minimal protein binding, less than 10%, primarily to albumin. |
| Volume of Distribution | Volume of distribution is approximately 0.5-0.8 L/kg, suggesting distribution primarily into extracellular fluid. |
| Bioavailability | Intramuscular bioavailability is approximately 80-90% compared to intravenous. |
| Onset of Action | Intravenous: onset within 5-15 minutes; intramuscular: onset within 15-30 minutes. |
| Duration of Action | Duration is 1-2 hours, but repeated doses may be needed due to short half-life and potential re-inhibition of acetylcholinesterase. |
| Molecular Weight | 172.6 |
1-2 g IV over 15-30 minutes, may repeat after 1 hour if muscle weakness persists, then every 3-8 hours as needed for 24-48 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based guidelines; use with caution in severe renal impairment (CrCl < 30 mL/min) and consider dose reduction or extended intervals based on clinical response. |
| Liver impairment | No specific Child-Pugh based modifications; monitor for adverse effects in hepatic impairment. |
| Pediatric use | 20-50 mg/kg IV over 30 minutes, maximum 2 g per dose; may repeat after 1 hour, then every 3-8 hours as needed. |
| Geriatric use | No specific dose adjustment; monitor renal function and consider lower initial doses due to age-related decreased renal function. |
| 1st trimester | Use only if clearly needed. No well-controlled studies; animal data limited. |
| 2nd trimester | Use only if clearly needed. No well-controlled studies; consider risk-benefit. |
| 3rd trimester | Use only if clearly needed. No well-controlled studies; consider risk-benefit. |
Clinical note
Comprehensive clinical and safety monograph for PROTOPAM CHLORIDE (PROTOPAM CHLORIDE).
| Placental transfer | Likely crosses placenta due to low molecular weight; data limited. |
| Breastfeeding | Excretion into breast milk unknown. Weigh benefit of treatment against potential risk to infant. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to pralidoxime or any component of the formulation
| Precautions | Should be used in conjunction with atropine for organophosphate poisoning; monitor for signs of organophosphate toxicity recurrence; use with caution in patients with myasthenia gravis; rapid intravenous administration may cause laryngospasm, muscle rigidity, or transient neuromuscular blockade. |
| Food/Dietary | No specific food restrictions; maintain hydration as vomiting or diarrhea may occur. |
| Clinical Pearls |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Pralidoxime chloride is a quaternary ammonium oxime. Available animal studies are insufficient to determine teratogenic risk. In humans, no adequate controlled studies exist. First trimester risk cannot be excluded. Second and third trimester use is indicated for treatment of organophosphate poisoning, where benefit outweighs unknown fetal risk. |
| Fetal Monitoring | Monitor maternal vital signs, oxygen saturation, and cardiac rhythm continuously during infusion. Assess for signs of organophosphate toxicity and response to therapy. Fetal heart rate monitoring if viable. Observe for maternal adverse effects: hypertension, tachycardia, muscle rigidity, laryngospasm. In severe poisoning, monitor maternal respiratory status and prepare for intubation. |
| Fertility Effects | No human data on fertility effects. Animal studies have not been conducted. Pralidoxime is used acutely in life-threatening poisoning, and its effect on fertility is likely negligible given short duration of therapy. |
| Administer intravenously at 1-2 g over 15-30 minutes; faster infusion may cause laryngospasm and muscle rigidity. Use in organophosphate poisoning only after atropinization. Monitor for pseudocholinesterase inhibition which can prolong succinylcholine effect. Half-life is 1.7 hours, requiring repeat dosing. Concomitant organophosphate exposure may necessitate prolonged therapy. |
| Patient Advice | This medication is used to reverse nerve agent or pesticide poisoning. · You may experience blurred vision, dizziness, or muscle weakness during treatment. · Avoid driving or operating machinery until symptoms resolve. · Inform your doctor immediately if you have difficulty breathing or swelling of the throat. · You may need repeated doses depending on your exposure level. |