Pharmacodynamics and Cardioactive Drugs

Study Notes

Pharmacodynamics

Pharmacodynamics studies the effects of drugs on the body and their mechanisms of action.
It examines the relationship between drug concentration at the site of action and the resulting pharmacological effects, including both desired and adverse outcomes.
Serum is the preferred sample for measuring circulating drug concentrations.

Cardioactive Drugs

Digoxin (Lanoxin):
- Average plasma half-life is 38 hours.
- Tissue concentrations are significantly higher than blood concentrations (15-30 times greater).
- Primarily eliminated by renal filtration of unbound digoxin.
Quinidine (Quinidex Extentabs, Cardioquin, Quinora):
- Derived from the Cinchona tree bark.
- Common formulations are sulfate and gluconate.
- Half-life is 6-8 hours.
- Primarily eliminated through hepatic metabolism.
- Potential adverse effects include nausea, vomiting, abdominal discomfort, thrombocytopenia, and tinnitus.
Procainamide and N-acetylprocainamide:
- Procainamide has a half-life of approximately 4 hours.
- Eliminated through a combination of renal filtration and hepatic metabolism.
Disopyramide (Norpace):
- Can be used as a quinidine alternative if quinidine's side effects are problematic.
- Adverse effects are dose-dependent and include anticholinergic effects (dry mouth, constipation) and cardiac effects (bradycardia, atrioventricular node blockage) at concentrations above 10 μg/mL.
- Half-life is roughly 7 hours.
- Primarily eliminated by renal filtration with some hepatic metabolism.

Description

This quiz focuses on pharmacodynamics, specifically studying the effects of various cardioactive drugs, including Digoxin and Quinidine. It delves into drug mechanisms, elimination pathways, and potential adverse effects. Test your knowledge on how these medications impact the body and their pharmacological significance.