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Influence of exercise on nitroglycerin plasma concentrations after transdermal application
R A Lefebvre1, M G Bogaert, O Teirlynck
1Heymans Institute of Pharmacology, University of Gent Medical School, Belgium.
British Journal of Clinical Pharmacology
|August 1, 1990
Summary
Transdermal nitroglycerin (NTG) levels increase significantly with physical activity. Exercise more than triples NTG plasma concentrations, while sitting also elevates levels, impacting drug bioavailability.
Area of Science:
- Pharmacology
- Exercise Physiology
Background:
- Nitroglycerin is a vasodilator used to treat angina.
- Transdermal nitroglycerin provides sustained drug delivery.
- The impact of physical activity on transdermal nitroglycerin pharmacokinetics is not fully understood.
Purpose of the Study:
- To investigate the effect of physical activity on plasma concentrations of transdermal nitroglycerin.
- To compare the effects of sitting versus exercise on nitroglycerin bioavailability.
Main Methods:
- Nine healthy subjects received transdermal nitroglycerin.
- Plasma nitroglycerin concentrations were measured during supine rest.
- Measurements were repeated during and after 20 minutes of sitting or exercise.
Main Results:
- Sitting nearly doubled average plasma nitroglycerin concentrations (0.31 to 0.55 ng/mL).
- Exercise caused a more substantial increase, peaking at 1.26 ng/mL 5 minutes post-exercise.
- These findings suggest altered drug bioavailability and systemic clearance.
Conclusions:
- Physical activity, particularly exercise, significantly enhances the plasma concentrations of transdermal nitroglycerin.
- Changes in bioavailability and systemic clearance are likely mechanisms behind exercise-induced increases.
- Clinicians should consider physical activity levels when prescribing transdermal nitroglycerin.