Indications
Pralidoxime chloride is an antidote used in hospital, together with Atropine, to treat poisoning by organophosphate insecticides (many common crop pesticides) and some nerve agents. It may also be used for overdose of certain medicines used in myasthenia gravis.
How It Works
Organophosphates block an enzyme called acetylcholinesterase, so a nerve chemical (acetylcholine) builds up and over-stimulates muscles, glands and nerves. Pralidoxime pulls the poison off the enzyme and reactivates it, which helps restore muscle strength, especially of the breathing muscles. It works best when given early, before the poison binds permanently. Atropine is still needed to control secretions and slow heartbeat.
Dosage and Administration
Pralidoxime is given only by a doctor or nurse in hospital, usually as a slow injection or infusion into a vein, sometimes followed by a continuous drip. The dose and duration depend on the severity of poisoning and the patient’s response and kidney function, as prescribed.
Interactions
It is used with Atropine; Pralidoxime may make the signs of atropine effect appear sooner. Avoid medicines that can worsen the poisoning or depress breathing, such as Succinylcholine, Morphine, Theophylline and Aminophylline, unless the treating team decides otherwise.
Contraindications
- Known allergy to Pralidoxime.
- Not effective for carbamate poisoning in all cases, so its use in such poisoning is decided by the doctor.
Side Effects
Possible effects include blurred or double vision, dizziness, headache, drowsiness, nausea, fast heartbeat, raised blood pressure, muscle stiffness or weakness, and pain at the injection site. Giving it too fast can cause breathing problems or muscle spasm.
Organophosphate poisoning is a medical emergency. Anyone exposed to an insecticide who has vomiting, sweating, drooling, small pupils, muscle twitching, breathing difficulty or confusion needs urgent hospital care.
Pregnancy and Lactation
Safety in pregnancy and breastfeeding is not well established, but because poisoning is life-threatening, it is given when the doctor judges it necessary.
Precautions and Warnings
Lower doses are used in kidney impairment. Use with care in myasthenia gravis. Patients need close monitoring of breathing, heart rate and blood pressure; breathing support may be required. Remove contaminated clothing and wash the skin to stop further absorption.
Overdose
Too much can cause dizziness, blurred vision, muscle weakness and breathing difficulty. Treatment is supportive in hospital, including breathing support if needed.
Therapeutic Class
Antidote, cholinesterase reactivator.
Storage
Hospital product: store as directed on the pack, below 30°C, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.