Reserpine

Reserpine is a drug that is used for the treatment of high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces mortality of people with hypertension. Although the use of reserpine as a solo drug has declined since it was first approved by the FDA in 1955, a review recommends use of reserpine and a thiazide diuretic or vasodilator in patients who do not achieve adequate lowering of blood pressure with first-line drug treatment alone. The reserpine-hydrochlorothiazide combo pill was the 17th most commonly prescribed of the 43 combination antihypertensive pills available In 2012. Reserpine is a drug that is used for the treatment of high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces mortality of people with hypertension. Although the use of reserpine as a solo drug has declined since it was first approved by the FDA in 1955, a review recommends use of reserpine and a thiazide diuretic or vasodilator in patients who do not achieve adequate lowering of blood pressure with first-line drug treatment alone. The reserpine-hydrochlorothiazide combo pill was the 17th most commonly prescribed of the 43 combination antihypertensive pills available In 2012. The antihypertensive actions of reserpine are largely due to its antinoradrenergic effects, which are a result of its ability to deplete catecholamines (among other monoamine neurotransmitters) from peripheral sympathetic nerve endings. These substances are normally involved in controlling heart rate, force of cardiac contraction and peripheral vascular resistance. At doses of 0.05 to 0.2 mg per day, reserpine is well tolerated; the most common adverse effect being nasal stuffiness. Reserpine has also been used for relief of psychotic symptoms. A review found that in persons with schizophrenia, reserpine and chlorpromazine had similar rates of adverse effects, but that reserpine was less effective than chlorpromazine for improving a person's global state. Reserpine irreversibly blocks the H+-coupled vesicular monoamine transporters, VMAT1 and VMAT2. VMAT1 is mostly expressed in neuroendocrine cells. VMAT2 is mostly expressed in neurons. Thus, it is the blockade of neuronal VMAT2 by reserpine that inhibits uptake and reduces stores of the monoamine neurotransmitters norepinephrine, dopamine, serotonin and histamine in the synaptic vesicles of neurons. VMAT2 normally transports free intracellular norepinephrine, serotonin, and dopamine in the presynaptic nerve terminal into presynaptic vesicles for subsequent release into the synaptic cleft ('exocytosis'). Unprotected neurotransmitters are metabolized by MAO (as well as by COMT), attached to the outer membrane of the mitochondria in the cytosol of the axon terminals, and consequently never excite the post-synaptic cell. Thus, reserpine increases removal of monoamine neurotransmitters from neurons, decreasing the size of the neurotransmitter pools, and thereby decreasing the amplitude of neurotransmitter release.