title: Efficacy and safety of intravenous terazosin in hypertensive patients. A preliminary report.
abstract: Single intravenous doses of 1, 2, and 5 mg of terazosin and placebo were administered in a randomized, double-blind, crossover fashion to 12 hypertensive adult patients. Supine and sitting blood pressures and pulse rates were monitored before and for 48 hours after drug administration. Blood and urine specimens were obtained periodically up to 48 hours after dosing; the concentration of terazosin in these samples was then determined. When compared with values before dosing, significant reductions (p less than or equal to 0.05) in supine diastolic blood pressure were observed from as early as 10 minutes after infusion of a terazosin dose and including most measurements through nine hours. From 20 minutes to five hours, most of the mean decreases in supine diastolic blood pressure following infusion of terazosin were significantly greater than those following infusion of placebo. Mean changes after terazosin administration ranged from -3 to -14 mm Hg, whereas mean changes after placebo administration ranged from +2 to -7 mm Hg. Pulse rates tended to increase slightly after terazosin administration and decrease slightly after placebo administration with few changes achieving statistical significance. The onset of the antihypertensive effect (at least a 10 percent decrease in supine diastolic blood pressure) occurred within two hours after most terazosin doses. The magnitude of the antihypertensive effect was similar at all three doses. The duration of action continued for at least six hours in 40 percent of those patients who showed a response within two hours. The peak antihypertensive effect occurred approximately four hours after administration of the terazosin dose (mean decreases of 17, 18, and 19 mm Hg after the 1-, 2-, and 5-mg doses, respectively). Adverse effects were mild. The most frequently reported side effects were headache, nasal congestion, and light-headedness. Terazosin decayed in a biexponential fashion with an elimination half-life of about 12 hours. There was no indication that nonlinear elimination occurred or that hypertensive disease influenced the disposition of the drug.
authors.forename: A
authors.initials: A
authors.lastname: Cohen
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000009:adverse effects / Q000378:metabolism; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism; D007275:Injections, Intravenous; D007700:Kinetics; D008875:Middle Aged; D010879:Piperazines / Q000009:adverse effects / Q000378:metabolism / Q000494:pharmacology*; D011224:Prazosin / Q000031:analogs & derivatives*; D011674:Pulse / Q000187:drug effects; D011897:Random Allocation
chemical_list: D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; C041226:Terazosin; D011224:Prazosin