Tolerance develops to sympathetic effects of khat in humans

Area of Science:

• Pharmacology
• Neuroscience
• Physiology

Background:

• Khat chewing is a widespread practice associated with psychostimulant and sympathetic nervous system effects.
• The mechanism of action for khat shares similarities with amphetamines.

Purpose of the Study:

• To investigate the development of tolerance to the physiological effects of khat.
• To compare the impact of a standard khat dose on physiological parameters in chronic consumers versus naive subjects.

Main Methods:

• A comparative study design was employed.
• Physiological parameters including blood pressure, pulse rate, respiratory rate, and body temperature were monitored in two groups: chronic khat consumers and naive individuals.
• Effects were assessed after consuming a standard dose of khat.

Main Results:

• Both naive and chronic khat users exhibited an increase in systolic blood pressure.
• Naive subjects showed a more pronounced increase in diastolic blood pressure, inversely correlated with a reduced pulse rate.
• Naive individuals also experienced greater increases in respiratory rate and body temperature compared to chronic users.
• All observed physiological effects subsided within 18 hours in both groups.

Conclusions:

• The findings support an amphetamine-like mechanism of action for khat.
• Evidence suggests that tolerance develops to the sympathetic nervous system effects of khat, particularly in chronic consumers.