Pharmacokinetics in patients with cardiac failure

Area of Science:

• Pharmacology
• Cardiology
• Clinical Pharmacy

Background:

• Cardiac failure impacts cardiac output, autonomic function, venous pressures, and fluid balance.
• These physiological changes affect tissue perfusion, potentially leading to hypoxia and congestion.
• Altered gastrointestinal motility and organ perfusion in heart failure can influence drug pharmacokinetics.

Purpose of the Study:

• To review how cardiac failure affects drug absorption, distribution, metabolism, and excretion.
• To highlight the need for dosage adjustments in patients with heart failure.
• To discuss specific drug examples and pharmacokinetic alterations observed in cardiac failure.

Main Methods:

• Literature review focusing on pharmacokinetic studies in cardiac failure.
• Analysis of drug disposition parameters like volume of distribution and clearance.
• Examination of specific drugs including lignocaine, procainamide, theophylline, digoxin, and quinidine.

Main Results:

• Decreased volume of distribution and clearance for lignocaine in heart failure.
• Impaired hepatic metabolism and reduced liver blood flow contribute to altered lignocaine clearance.
• Reduced theophylline metabolism and potential accumulation of active metabolites for lignocaine and procainamide.
• Digoxin clearance may be lower than predicted, and quinidine levels may increase due to reduced distribution.

Conclusions:

• Cardiac failure significantly alters drug pharmacokinetics, necessitating individualized dosage regimens.
• Variability in pharmacokinetic changes requires therapeutic drug monitoring for optimal patient outcomes.
• Specific assays are recommended for drugs like quinidine, especially in patients with coexisting renal insufficiency.