Physostigmine

Physostigmine is an antidote used to reverse the effect of anticholinergic toxicity. 

• Physostigmine is available under the following different brand names:

Adult and pediatric dosage

Injectable solution

• 1mg/mL

Anticholinergic Toxicity

Adult dosage

• Initial: 0.5-2 mg slow IVP (not to exceed 1 mg/min); keep atropine nearby for immediate use
• If no response, repeat every 20 minutes as needed
• If the initial dose is effective may give an additional 1-4 mg every 30-60 minutes as needed

Pediatric dosage

• 0.02 mg/kg/dose slow IVP (not to exceed 0.5 mg/min); may repeat every 5-10 minutes as needed, not to exceed a cumulative dose of 2 mg 

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

Common side effects of Physostigmine include:

• nausea,
• vomiting,
• increased salivation,
• stomach cramps,
• diarrhea, and
• excessive sweating.

Serious side effects of Physostigmine include:

• increased urination or bowel movements,
• severe or worsening nausea or vomiting,
• increased sweating,
• blurred vision,
• bradycardia,
• excessive salivation, and 
• signs of an allergic reaction: hives, difficult breathing, swelling of the face, lips, tongue, or throat.

Rare side effects of Physostigmine include:

• none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Physostigmine has severe interactions with no other drugs.
• Physostigmine has serious interactions with the following drug:
  • triamcinolone acetonide injectable suspension
• Physostigmine has moderate interactions with at least 66 other drugs.
• Physostigmine has minor interactions with at least 22 other drugs. 

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Salicylate allergy
• Asthma, gangrene, diabetes, cardiovascular disease, mechanical obstruction of the intestinal or urogenital tract, or any vagotonic state
• Concurrency with choline esters or depolarizing neuromuscular blocking agents

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Physostigmine?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Physostigmine?”

Cautions

• Keep atropine ready for potential cholinergic symptoms.

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy.
• Lactation
  • Unknown if excreted in breast milk; caution advised