Chronopharmacology of strophanthin and inderal: an experimental study

Area of Science:

• Pharmacology
• Chronobiology
• Toxicology

Background:

• Understanding daily variations in drug response is crucial for optimizing therapeutic outcomes.
• Cardiac glycosides like strophanthin can have narrow therapeutic windows, making timing of administration critical.
• Circadian rhythms influence physiological processes, including drug metabolism and sensitivity.

Purpose of the Study:

• To investigate the circadian rhythm of tolerance to arrhythmogenic and lethal doses of strophanthin in guinea pigs and white mice.
• To examine the daily changes in sensitivity to the antiarrhythmic dose of inderal.
• To determine if there is a correlation between strophanthin toxicity and inderal sensitivity rhythms.

Main Methods:

• Chronopharmacological studies were conducted on 54 guinea pigs and 126 white mice.
• Drug administration and testing occurred at 4-hour intervals over a 24-hour period.
• Data analysis involved cosinor analysis and non-linear least-square methods to identify circadian fluctuations.

Main Results:

• Strophanthin toxicity demonstrated a circadian rhythm, with maximum toxicity observed during late evening, night, and early morning hours.
• A significant circadian rhythm was also observed for sensitivity to the threshold antiarrhythmic dose of inderal.
• The acrophases (peak times) for circadian rhythms of chronotolerance to strophanthin and chronosensibility to inderal were found to be nearly identical.

Conclusions:

• Both strophanthin toxicity and inderal sensitivity exhibit significant circadian variations in rodents.
• The synchronized circadian rhythms suggest a potential for chronotherapeutic strategies to optimize the administration of strophanthin and inderal.
• Further research is warranted to explore the clinical implications of these findings in human medicine.