Effects of Exercise on Pharmacokinetics of drugs

Pharmacokinetics describes

the realtionship between the absorption, distribution, metabolism, and excretion of a drug and its effects and duration of action

exercise alters a number of

physiological parameters including changes in CO, BF to activie skeletal muscles, skin, etc.

Exercise has some (little) effects on

absorption of orally administered drugs

Physical exercise seems tohave the greatest potential to affect the

absorption and distribution of durgs that are administered by subcutaneous, intramuscular or transdermal routes

Physical exercise changes several body fucntions that may affect drug absorption from the

GI tract

Many drugs taken orally are absorped through the

intensine via splanchnic blood supply

What does exercise do to splanchinic BF

reduces it thereby less drug is absorbed from the GI tract to blood vessels

Lactic acid is produced when you exercise which can

decrease the pH of blood and musclewhy

Why does pH matter?

it can alter drug ionization and polarize so it can increase or decrease

during exercise the sympathetic tone increases with release of catecholamines, this will

inhibit gastric emptying and thereby inhibit absorption

Why will durg absorption from sites in actively exercising tissue increased dured exercise

because exercise increases blood flow to active tissues while blood flow diminishes in non-exercising organs

What is an example of a drug being absorption increasing with exercise after subcutaneous injection into muscle

insulin

It has been observed that exercise both prior to and following drug administration

incrases the realtive rate of drug absorption into the system ic circualtion

What does increase in skin temperature have to do with absorption

it may incrase skin blood flow and tehreby increases trans-dermal absorption

Which drug has been found to have major effect with increases in skin temperature

nigroglycerine patch, and so it may be beneficial to the exercising angina patient

exhaustive exercise can cause a __________ of renal blood flow due to increased renal sympathetic acitivty and _____

reduction: thereby reduced elimination of drugs

execises increases CO, but diverts blood away from _______ thereby

liver; decreases the clearance of drugs