Pharmacokinetics of acetazolamide in healthy volunteers after short- and long-term exposure to high altitude.

Exposure to high altitude results in significant physiologic changes and may precipitate mountain sickness, ranging from mild symptoms above 2,500 m to severe symptoms above 4,000 m. In a previous study, changes in the pharmacokinetics of meperidine were observed after exposure to high altitude. This study was conducted to investigate whether similar changes occur for acetazolamide, which is prescribed for prophylaxis of acute mountain sickness.

Urinary excretion of acetazolamide in healthy volunteers after short- and long-term exposure to high altitude.

Acetazolamide is recommended for the prophylaxis of acute mountain sickness symptoms which sets in on climbing to high altitudes (H) above 2,500 m. It is primarily excreted unchanged in urine. In a previous study, we reported on the changes in urinary excretion of meperidine and its metabolite normeperidine on exposure to high altitude.

Pharmacokinetics of meperidine in healthy volunteers after short- and long-term exposure to high altitude.

Increased numbers of erythrocytes have been shown ex vivo to increase meperidine uptake, and one of the major physiologic changes that occurs at high altitude is an increase in hematocrit and erythrocytes. A study was therefore conducted to evaluate the effects of high altitude on the pharmacokinetics of meperidine. Intramuscular doses (0.

Urinary excretion of meperidine and normeperidine in man upon acute and chronic exposure to high altitude.

The urinary excretion of unchanged meperidine (M) varies with change of pH and metabolism. Since exposure of man to high altitude (H) may cause significant physiologic changes, we investigated its effects on the urinary excretion of M. The study was carried out in 3 groups of healthy, male volunteers (ages 18-20 years): at sea level (L), at 4360 m the day after arrival at H (HA), and at 4360 m in subjects residing for > 10 months at H (HC).

Meperidine uptake and binding to human blood ex vivo.

Many drugs are bound to plasma proteins (PR) and/or to erythrocytes (RBC). The RBC count may change due to physiologic factors such as exposure to high altitude, or pathologic conditions such as anemia or as consequence of cancer treatment. The purpose of the investigation was to study the influence of 1) drug concentration, and 2) number of RBC on erythrocyte uptake or binding using meperidine as a model drug (M).