Guanethidine in antihypertensive therapy: experience with an oral loading regimen.

Guanethidine sulfate, a potent antihypertensive agent with a prolonged duration of action, was given in large oral doses to eight hypertensive patients in a loading technique. Blood pressure control resulted within one to three days without side effects, with total loading doses varying from 125 to 650 mg. Based on the drug's pharmacokinetic properties, a maintenance dose required to sustain the desired antihypertensive effects was calculated from the loading dose for each individual. Blood pressure was satisfactorily controlled in the seven patients followed for at least 12 months, and no modification of the calculated guanethidine dose was required. Side effects were minimal and well tolerated. The ease of initial blood pressure regulation with this regimen and the precision with which a maintenance dose can be determined suggest that guanethidine deserves a more prominent role in the therapy of established hypertension.