Cholinergic and Anticholinergic Drugs: Mechanisms, Dosage, and Effects

Cholinergic and anticholinergic drugs play a crucial role in medical treatments. Understanding their mechanisms, dosage, therapeutic indications, and contraindications is vital for effective clinical use.

Mechanism of Action

Cholinergic drugs mimic the action of acetylcholine, stimulating the parasympathetic nervous system. Anticholinergic drugs inhibit acetylcholine, reducing parasympathetic effects.

Classification

• Cholinergic drugs: Direct-acting and indirect-acting
• Anticholinergic drugs: Muscarinic receptor blockers and nicotinic receptor blockers

Dosage and Administration of Anticholinergic Drugs

Anticholinergic medications vary in dosage based on the specific drug and indication. Some common examples include:

• Atropine: 0.5–1 mg IV for bradycardia
• Ipratropium: 20–40 mcg inhaled for COPD
• Oxybutynin: 5 mg orally for overactive bladder

Adverse Effects

Common side effects of anticholinergic drugs include:

• Dry mouth
• Blurred vision
• Constipation
• Urinary retention

Therapeutic Indications

Anticholinergic drugs are used for conditions such as:

• Asthma and COPD
• Parkinson’s disease
• Gastrointestinal disorders

Contraindications

These drugs are contraindicated in patients with:

• Glaucoma
• Prostatic hypertrophy
• Cardiovascular disease