Study of the pharmacokinetics of various drugs under conditions of antiorthostatic hypokinesia and the pharmacokinetics of acetaminophen under long-term spaceflight conditions.

Objectives: To study the pharmacokinetics and relative bioavailability of drugs of different chemical structure and pharmacological action under conditions simulating the effects of some factors of spaceflight, as well as the peculiarities of the pharmacokinetics of acetaminophen under long-term spaceflight conditions.

Methods: The pharmacokinetics of verapamil (n=8), propranolol (n=8), etacizine (n=9), furosemide (n=6), and acetaminophen (n=7) in healthy volunteers after a single oral administration under normal conditions (background) and under antiorthostatic hypokinesia (ANOH), the pharmacokinetics of acetaminophen in spaceflight members under normal ground conditions (background) (n=8) and under prolonged spaceflight conditions (SF) (n=5) were studied.

Results: The stay of volunteers under antiorthostatic hypokinesia had different effects on the pharmacokinetics and bioavailability of drugs: Compared to background, there was a decreasing trend in V for verapamil (-54 Δ%), furosemide (-20 Δ%), propranolol (-8 Δ%), and acetaminophen (-9 Δ%), but a statistically significant increase in V was found for etacizine (+39 Δ%); there was an increasing trend in Cl for propranolol (+13 Δ%) and acetaminophen (+16 Δ%), and a decreasing trend in Cl for etacizine, verapamil, and furosemide (-22, -23 and -9 Δ% respectively) in ANOH.

Study of the pharmacokinetics of various drugs under conditions of antiorthostatic hypokinesia and the pharmacokinetics of acetaminophen under long-term spaceflight conditions.

Objectives: To study the pharmacokinetics and relative bioavailability of drugs of different chemical structure and pharmacological action under conditions simulating the effects of some factors of spaceflight, as well as the peculiarities of the pharmacokinetics of acetaminophen under long-term spaceflight conditions.

Methods: The pharmacokinetics of verapamil (n=8), propranolol (n=8), etacizine (n=9), furosemide (n=6), and acetaminophen (n=7) in healthy volunteers after a single oral administration under normal conditions (background) and under antiorthostatic hypokinesia (ANOH), the pharmacokinetics of acetaminophen in spaceflight members under normal ground conditions (background) (n=8) and under prolonged spaceflight conditions (SF) (n=5) were studied.

Results: The stay of volunteers under antiorthostatic hypokinesia had different effects on the pharmacokinetics and bioavailability of drugs: Compared to background, there was a decreasing trend in V for verapamil (-54 Δ%), furosemide (-20 Δ%), propranolol (-8 Δ%), and acetaminophen (-9 Δ%), but a statistically significant increase in V was found for etacizine (+39 Δ%); there was an increasing trend in Cl for propranolol (+13 Δ%) and acetaminophen (+16 Δ%), and a decreasing trend in Cl for etacizine, verapamil, and furosemide (-22, -23 and -9 Δ% respectively) in ANOH.