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Transcranial Doppler to evaluate the effects of antihypertensive medication on cerebral blood flow velocity
S C Fagan1, V Bindlish, S Robert
1College of Pharmacy, Wayne State University, Detroit, MI 48202.
Insights
Oral nifedipine directly reduces cerebral blood flow velocity in elderly hypertensive patients. This study supports using transcranial Doppler for investigating drug effects on brain blood vessels.
Area of Science:
- Cardiovascular Medicine
- Neurology
- Pharmacology
Background:
- Hypertension is a common condition in the elderly.
- Cerebral blood flow regulation is crucial for brain health.
- Understanding drug effects on cerebral vasculature is important for patient care.
Purpose of the Study:
- To investigate the effect of oral nifedipine on cerebral blood flow velocity.
- To determine the relationship between nifedipine concentration and cerebral blood flow.
- To assess the utility of transcranial Doppler in pharmacodynamic studies.
Main Methods:
- Six elderly hypertensive patients were enrolled.
- Transcranial Doppler was used to measure middle cerebral artery (MCA) flow velocity.
- Serial measurements of blood pressure, MCA velocity, and nifedipine serum concentrations were taken over 8 hours.
Main Results:
- A significant inverse relationship was observed between MCA flow velocities and nifedipine serum concentrations.
- This relationship was independent of changes in blood pressure.
- Nifedipine demonstrated a direct vasodilatory effect on cerebral vessels.
Conclusions:
- Oral nifedipine has a direct vasodilatory effect on cerebral blood vessels.
- Transcranial Doppler is a valuable tool for pharmacodynamic investigations of the cerebral vasculature.
- These findings support nifedipine's use in managing hypertension with potential cerebrovascular benefits.
Abstract:
The effect of oral nifedipine on cerebral blood flow velocity was studied in six elderly hypertensive patients using transcranial Doppler. Serial measurements of blood pressure (BP), middle cerebral artery (MCA) flow velocity and nifedipine serum concentrations were obtained over an 8-hour period. The authors found a significant inverse relationship between MCA velocities and nifedipine concentrations, independent of BP changes. These results are consistent with a direct vasodilatory effect of nifedipine on cerebral vessels and support the use of TCD in pharmacodynamic investigations of the cerebral vasculature.