Guanabenz, an antihypertensive agent for oral administration-, is an aminoguanidine derivative, 2,'6-dichlorobenzylideneamina-guanidine acetate. It is white to an almost white powder having not more than a slight odor. Sparingly soluble in water and in 0.1 N hydrochloric acid; soluble in alcohol and in propylene glycol. Guanabenz is an orally active central alpha-2 adrenergic agonist. Its antihypertensive action appears to be mediated via stimulation of central alpha-adrenergic receptors, resulting in a decrease of sympathetic outflow from the brain at the bulbar level to the peripheral circulatory system. In clinical trials, guanabenz acetate, given orally to hypertensive patients, effectively controlled blood pressure without any significant effect on glomerular filtration rate, renal blood flow, body fluid volume or body weight. The Myelin Repair Foundation and the National Institutes of Health (National Institute of Neurological Disorders and Stroke) are developing guanabenz for the treatment of multiple sclerosis. Unlike the currently available treatment for multiple sclerosis that suppresses the immune system, guanabenz, an FDA approved the drug for the treatment of high blood pressure, has a potential to reduce the loss of myelin by protecting and repairing myelin-producing cells in the brain from damage. Phase I development is underway in the US.

Dinoprost is the synthetic or partially synthetic, naturally-occurring prostaglandin F2 alpha (trade mark Prostin F2 alpha). Dinoprost has been used for therapeutic termination of pregnancy. Although the exact mode of action in pregnancy termination in humans is not fully defined, when Prostin F2 alpha is administered by the intrauterine route it initiates rhythmical uterine contractions which, if continued for a sufficient time, are capable of expelling the contents of the uterus. Sensitivity of the pregnant uterus to prostaglandins is lower during early and mid-pregnancy than at term.

ETRYPTAMINE (MONASE®), similar to the hallucinogenic tryptamines, is an inhibitor of monoamine oxidase, introduced for use as an antidepressant. It was withdrawn from the market due to problems with agranulocytosis and other side effects. However, it's activity is still under scientific investigation.