Effect of Exercise and Environmental Heat on Drug Kinetics.
Abstract
The effects of physical exercise and heat exposure on the pharmacokinetic behavior of some model drugs were investigated in normal volunteers. Drugs were chosen to represent particular kinetic processes. Exercise was mild to moderate and environmental temperature was either 22 C or 40 C. Under heat exposure and exercise, theophylline exhibited prolonged half-life and reduced clearance, suggesting the need for dosage adjustment in moderately active individuals. Exercise influenced digoxin kinetics by shortening the time to peak, probably by enhancing the drug's absorption. The plasma kinetics of quinidine were unchanged under exercise conditions. However, urinary excretion of the drug was significantly higher during exercise than at rest, and this correlated with increased urinary output during exercise. Exercise and heat exposure prolonged the time of distribution of intravenously administered propanolol, while other pharmacokinetic parameters relating to propanolol remained unchanged. The half lives (T1/2) of both sulfamethoxazole and trimethoprim that were administered as co-trimoxazole were not significantly altered. The absorption of methylsalicylate that was applied on the skin was markedly influenced by the conditions tested. Thus, the amount of salicylate that was absorbed increased three fold while the subjects were exposed to either heat or exercise or both.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1984
- Accession Number
- ADA145405
Entities
People
- A. Danon