Clinical pharmacological aspects on nitrate tolerance.

Area of Science:

• Pharmacology
• Cardiovascular Medicine
• Clinical Therapeutics

Background:

• Nitrate tolerance is a significant clinical issue, particularly in managing cardiovascular conditions.
• Rapid tolerance development is observed in the systemic resistance vascular bed, with cross-tolerance among various nitrates.
• Divergent findings exist regarding tolerance development in systemic capacitance and pulmonary vascular beds, potentially due to differing patient populations (ischemic heart disease vs. congestive heart failure) and nitrate formulations.

Purpose of the Study:

• To review and synthesize current understanding of nitrate tolerance.
• To highlight inconsistencies in existing research on nitrate tolerance development.
• To propose standardized methodologies for future nitrate tolerance studies.

Main Methods:

• Review of existing literature on nitrate tolerance and pharmacokinetics.
• Analysis of divergent findings in studies involving different patient groups and nitrate preparations.
• Discussion of pharmacokinetic variability (bioavailability, clearance, volume of distribution).

Main Results:

• Strong evidence supports rapid nitrate tolerance in the systemic resistance vascular bed.
• Cross-tolerance between different nitrate drugs is well-established.
• Pharmacokinetic data for nitrates are complex and highly variable, impacting tolerance assessment.

Conclusions:

• Nitrate tolerance mechanisms require further elucidation, especially in specific patient populations like those with congestive heart failure.
• Future studies should utilize homogeneous patient groups with well-defined hemodynamics.
• Employing short-half-life nitrates administered via intravenous infusion is recommended for consistent and reproducible research on nitrate tolerance.