Anticholinergic Poisoning - Causes, Symptoms, Diagnosis, Treatment, and Prevention

Introduction

Anticholinergic drugs are neurotransmitters that help function in the body by transferring signals between the cells. For example, these chemical messengers block acetylcholine's action and help control involuntary muscle movements caused by some conditions like Parkinson's disease. The toxicity caused by this drug due to overdose can be intentional or accidental, leading to severe health complications that can also be fatal. Though the drug has many medical implications, it can also produce side effects through safe use; therefore, it must be taken cautiously.

What Are the Causes of Anticholinergic Poisoning?

Anticholinergic poisoning can be caused due to several reasons, such as:

• In addition, misuse or substance abuse of anticholinergic drugs can cause toxicity in the body, and safe drug use can cause minor side effects.

• Certain medications also show anticholinergic properties and can produce toxic symptoms. These medications are antipsychotics, antihistamines, mydriatics, antidepressants, and antispasmodics.

• Some plants contain belladonna alkaloids and are also a source of intentional or accidental anticholinergic toxicity. In addition, these alkaloids produce hallucination effects and thus are used for intoxication or abuse.

What Is the Mechanism of Action of Anticholinergic Drugs?

Anticholinergic drugs inhibit the activity and effects of acetylcholine at central receptors and peripheral muscarinic. This affects the exocrine glands and smooth muscles of the body and further reduces saliva and sweat secretion. Muscarinic activity is also inhibited, which causes rapid heartbeat and affects the heart, whereas atropine is absorbed well in the central nervous system and thus produces effects. In addition, anticholinergic drugs can lead to decreased gastrointestinal motility, leading to delayed absorption of the drug and prolonged toxicity in the body for up to 2-3 days.

What Are the Signs and Symptoms of Anticholinergic Poisoning?

Symptoms Produce due to the effect on the central nervous system:

• Confusion.

• Delirium.

• Hallucinations.

• Psychosis.

• Psychomotor agitation.

• Seizures.

• Coma.

Symptoms produced due to effects of the peripheral nervous system:

• Hyperthermia.

• Vasodilation.

• Tachycardia.

• Blurry vision.

• Diffuse erythema.

• Skin dryness.

• Urinary retention.

What Are the Uses of Anticholinergic Drugs?

Anticholinergic drugs are used for treating various conditions, such as:

• Asthma.

• Chronic obstructive pulmonary disorder (COPD).

• Motion sickness.

• Dizziness.

• Parkinson’s disease symptoms like involuntary muscle function.

• Gastrointestinal disorders.

• Urinary incontinence.

• Muscarine or organophosphorus poisoning.

What Are the Commonly Used Anticholinergic Drugs?

Some examples of commonly used anticholinergic drugs are:

• Atropine.

• Cyclopentolate.

• Benztropine mesylate.

• Oxybutynin.

• Flavoxate.

• Solifenacin.

• Ipratropium.

• Belladonna alkaloids.

What Are the Side Effects Produced by Anticholinergic Drugs?

Side effects produced by safely using anticholinergic drugs include:

• Blurry vision.

• Constipation.

• Sedation.

• Drowsiness.

• Dry mouth.

• Hallucinations.

• Decreased saliva production.

• Decreased sweating.

• Trouble urinating.

• Delirium.

• Confusion.

• Memory disorders.

How Is Anticholinergic Poisoning Diagnosed?

Diagnostic tests can be performed to detect anticholinergic poisoning. These may include:

• Blood glucose, gas, creatinine, electrolytes, and creatine kinase analysis can help detect toxicity due to anticholinergic drugs.

• Electrocardiography (ECG) and oximetry are also helpful.

• Further diagnosis can be confirmed based on the effects of antidote therapy that can inhibit acetylcholinesterase.

• Urine toxicology assay.

What Are the Treatments for Anticholinergic Poisoning?

• Stop the use of any causative agent immediately.

• Initially, the person must be provided with supportive care, and his vitals, cardiac output, and urine output must be monitored continuously. Then, an agitated person must be given benzodiazepines intravenously as the first line of the drug to minimize the risk of symptoms like rhabdomyolysis and hyperthermia.

• Antidote: Physostigmine salicylate IV 0.5 to 2 mg can be given to an adult for treating agitated delirium, and children can be given 0.5 mg IV in severe cases. This drug is usually given after consulting a toxicologist because it can produce adverse effects like heart block and bradycardia. It is also contraindicated in case of tricyclic antidepressant overdose, QRS complex on ECG for a prolonged period, seizure disorder, and atrioventricular conduction disorder.

• Oral-activated charcoal (AC) can be used for decontamination to treat toxicity within one hour of ingestion because anticholinergic can lead to impaired gastrointestinal mobility.

• An agitated person may also require physical or chemical (sedative) restraints to protect them from physical harm or injury. Sometimes mechanical ventilation or endotracheal intubation is also needed in severe cases.

• Some treatment options, such as hemoperfusion, hemodialysis, peritoneal dialysis, and excessive charcoal treatment, are ineffective in treating anticholinergic toxicity.

• Urine retention is managed with a urinary catheter.

What Are the Preventive Measures for Anticholinergic Poisoning?

• Avoid Overdose- Anticholinergic drug overdose or taken in combinations should be avoided to prevent fatal condition-producing signs like dizziness, fever, or hallucinations.

• Avoid Overheating- Keeping the body hydrated is essential if a person takes anticholinergic drugs to keep body temperature low. Decreased sweating can be the side effect experienced in such conditions.

• Avoid Alcohol- Alcohol consumption must be discouraged with anticholinergic drugs as it can also produce side effects and lead to adverse drug reactions.

• Other Medical Conditions- If a person is already suffering from any medical condition, anticholinergic drugs must not be used without consulting the doctor.

• Other Drug Interactions- A person already taking any medication must consult a physician before taking anticholinergic drugs to avoid fatal drug interactions.

What Are the Complications Associated With Anticholinergic Poisoning?

Complications include:

• Cardiovascular failure.

• Respiratory failure.

• Seizures.

• Rhabdomyolysis.

• Disability.

• Death.

What Are the Other Differential Diagnoses of Anticholinergic Poisoning?

• Salicylate toxicity.

• Sepsis.

• Uremia.

• Meningitis.

• Serotonin syndrome.

• Sympathomimetic toxicity.

• Malignant hyperthermia.

• Encephalitis.

• Neurotrauma.

• Neuroleptic malignant syndrome.

What Are the Contraindications for Using Anticholinergic Drugs?

Anticholinergic drugs should not be given under the following conditions:

• Liver disease.

• Heart failure.

• Severe constipation.

• Enlarged prostate.

• Glaucoma.

• Down syndrome.

• Tachycardia.

• Hiatal Hernia.

• Hyperthyroidism.

• Myasthenia gravis.

• Urinary tract blockage.

• Severe dryness.

Conclusion:

Anticholinergic poisoning is a severe condition that can lead to coma or even death in several cases. Early diagnosis and treatment can be life-saving for a person if the issue is reported on time. However, anticholinergic toxicity sometimes becomes difficult to treat because the condition resembles other toxicities if proper drug history is absent. Therefore, the doctor must analyze the case cautiously to confirm the diagnosis and provide the necessary treatment for the intoxication to minimize the effect. Also, the person on anticholinergic medication must be careful while taking the drug dose to avoid any accidental overdose incidents.