Skip to Content

Protopam Chloride Side Effects

Generic Name: pralidoxime

Note: This page contains side effects data for the generic drug pralidoxime. It is possible that some of the dosage forms included below may not apply to the brand name Protopam Chloride.

For the Consumer

Applies to pralidoxime: injection injectable, injection powder for solution

As well as its needed effects, pralidoxime (the active ingredient contained in Protopam Chloride) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking pralidoxime, check with your doctor or nurse immediately:

More common:
  • Blurred or double vision
  • change in near or distance vision
  • difficult or rapid breathing
  • difficulty in focusing the eyes
  • difficulty with speaking
  • dizziness
  • fast, pounding, or irregular heartbeat or pulse
  • muscle stiffness or weakness
  • pain at the injection site (after injection into a muscle)
Incidence not known:
  • Deep or fast breathing with dizziness
  • numbness of the feet, hands, and around the mouth

Minor Side Effects

Some pralidoxime side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Drowsiness
  • headache
  • nausea

For Healthcare Professionals

Applies to pralidoxime: intravenous powder for injection


Pralidoxime has been well tolerated in most cases; however, it should be considered that the desperate condition of the organophosphate-poisoned patient generally masks the minor signs and symptoms noted in normal subjects who have not been exposed to anticholinesterase poisons. Many of the signs and symptoms of organophosphate poisoning are similar to the side effects of pralidoxime (the active ingredient contained in Protopam Chloride) It may be difficult to ascertain which effects are due to the drug and which are toxic symptoms produced by atropine or the organophosphate compounds.[Ref]


Cardiovascular side effects have included tachycardia and increased systolic and diastolic blood pressure in normal subjects. Tachycardia has also occurred after excessively rapid infusions. Asystole and cardiac arrest have been reported; however, causality is unclear due to the presence of atropine and an organophosphate insecticide.[Ref]


Musculoskeletal side effects have included muscle weakness in normal subjects. Laryngospasm and muscle rigidity have occurred after excessively rapid infusions.[Ref]

Nervous system

Nervous system side effects have included dizziness, headache, and drowsiness in normal subjects.[Ref]


Respiratory side effects have included hyperventilation in normal subjects.[Ref]


Ocular side effects have included blurred vision, diplopia, and impaired accommodation in normal subjects.[Ref]


Gastrointestinal side effects have included nausea in normal subjects.[Ref]


Metabolic side effects have included transient elevations of creatine phosphokinase in all normal subjects.


Hepatic side effects have included elevations of AST and/or ALT in normal subjects.[Ref]

Elevated AST and/or ALT were reported in 1 of 6 normal subjects given 1200 mg intramuscularly and 4 of 6 normal subjects given 1800 mg intramuscularly. Levels returned to normal in about 2 weeks.[Ref]


Local side effects have included mild to moderate injection site pain, 40 to 60 minutes after intramuscular injection.[Ref]


1. "Product Information. Protopam Chloride (pralidoxime)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

2. Scott RJ "Repeated asystole following PAM in organophosphate self-poisoning." Anaesth Intensive Care 14 (1986): 458-60

It is possible that some side effects of Protopam Chloride may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.