Tricyclic antidepressants and peripheral anticholinergic activity.

Area of Science:

• Pharmacology
• Autonomic Nervous System
• Clinical Trials

Background:

• Tricyclic antidepressants (TCAs) are widely used for depression.
• Peripheral anticholinergic side effects are common with TCAs.
• Understanding these effects is crucial for patient management.

Purpose of the Study:

• To assess the peripheral anticholinergic activity of acute doses of amitriptyline, desipramine, and doxepin.
• To compare these effects against a placebo using physiological measures.
• To identify reliable methods for evaluating TCA autonomic effects.

Main Methods:

• Normal male volunteers received single acute doses of amitriptyline (50 mg), desipramine (50 mg), doxepin (100 mg), or placebo.
• Physiological measures included salivary flow, finger sweating, supine and standing blood pressure, and standing pulse.
• Statistical analysis was used to compare drug effects against placebo and among drugs.

Main Results:

• Amitriptyline and doxepin significantly reduced salivary flow and finger sweating compared to placebo.
• Desipramine did not produce significant changes in salivation or sweating.
• Significant differences in blood pressure and pulse were observed among the tested drugs.

Conclusions:

• Amitriptyline and doxepin exhibit significant peripheral anticholinergic activity.
• Desipramine demonstrates minimal peripheral anticholinergic effects at the tested dose.
• A battery of tests measuring salivation, perspiration, and pulse-blood pressure provides a reliable assessment of TCA peripheral autonomic effects.