Clinical Drug Experience Knowledgebase

Mephentermine, an amphetamine-derived phenethylamine, is an alpha 1 adrenergic receptor agonist and a hypertensive drug. Mephentermine is mainly used as a vasopressor agent with a sympathomimetic action, primarily causing release of noradrenaline and increasing cardiac output due to positive inotropic effect on the myocardium. The injectable preparation of mephentermine is commonly used for the short-term treatment of various hypotensive states such as shock or hypotension accompanying myocardial infarction or spinal anesthesia or surgical procedures like cesarean section. There is evidence on the fetal metabolic effect and placental transfer of mephentermine. However, a few studies have shown that mephentermine is as effective as phenylephrine in preventing maternal hypotension after spinal anesthesia and has similar effect on neonatal outcome. It is being widely used in developing countries like India as it is much more economical than phenylephrine and offers ease of use as it does not necessitate multiple dilutions as injectable. It is also available in India as 10 mg oral tablets. Despite it was thought earlier to have a little stimulant effect its abuse potential has increased, especially in sports due to its stimulant properties. Like amphetamines, it has shown to increase athletic performance in strength exercises and endurance in a dose of 14 mg/70 kg body weight. It has been proposed that phentermine, which is the main metabolite of mephentermine, acts by inhibiting monoaminoxidases A and B. Mephentermine adverse effects has been related to CNS simulation, excessive rises in blood pressure, and arrhythmias. Wyamine Sulfate (brand name of mephentermine sulfate) approved by FDA in 1951 was discontinued in USA.   ^NCATS