Rauwolfia serpentina, also known as "rauvolfia," "Indian snakeroot" and "serpentwood," is a woody evergreen sub-shrub, originally from India, Indochina, Borneo, Sri Lanka and Sumatra. Its roots, which have a bitter taste, contain reserpine, an alkaloid substance with a powerful sedative effect that has various medicinal uses. Some herbalists, though, discourage the use of rauwolfia because of the numerous adverse reactions it may cause.
Rauwolfia is used in the treatment of conditions like hypertension, nervousness and insomnia. It is known in India as the "insanity herb," being recommended in mental disorders. Reserpine and its derivatives are important ingredients in many prescription tranquilizers.
Although also included in folk remedies for cancer, liver disease and mental illness, according to the American Cancer Society, there is no scientific evidence to support these uses. In its native India, the plant has also been used in a paste solution applied topically for the treatment of snakebites and scorpion stings.
Reserpine is a drug approved by the U.S. Food and Drug Administration (FDA) for prescription medicine and it can be found in pill and injectable form. In the United Kingdom, snakeroot is also available by prescription only and in Germany it is approved for the treatment of hypertension.
Rauwolfia is also sold as a dietary supplement in the United States and can be found whole, raw and in powder form for both internal and external use.
According to the 2004 edition of "The Physicians' Desk Reference for Herbal Medicines," rauwolfia should not be taken by people who suffer from depression, ulcerations or pheochromocytoma (tumor of the adrenal gland). Also, women who are breastfeeding or pregnant should avoid this substance, as it can pass through the breast milk and may have unknown effects on the fetus.
Significant increase in blood pressure might occur when the drug is taken along with cough and flu medicine or appetite suppressants. Alcohol should not be consumed in association with reserpine because it can cause severe impairment of reactions. Anti-psychotics and barbiturates increase the drug's effects. If taken in combination with digitalis glycosides, it can cause slow heart rate. The drug effects are reduced and other undesired muscle movement effects may occur when it is taken in association with levodopa (medication for Parkinson's disease).
Side effects of rauwolfia include nasal congestion, depression, tiredness and erectile dysfunction. Reserpine can cause severe depression, increase of appetite and weight gain. Drowsiness may occur, too, so the operation of vehicles or heavy machinery must be done with precaution.
Reserpine is known to cause cancer in mice and people who use it increase their cancer risk rates slightly. The U.S. National Toxicology Program classifies it as a "probable cancer-causing substance."
The use of rauwolfia is recorded in Hindu texts dating from around 500 B.C. In the West, it was unknown until 1943, when an Indian doctor wrote an article about the plant, emphasizing the efficiency of its sedative effects in treating high blood pressure. In the United States, reserpine had a rapid success in replacing the use of electric shock therapy and lobotomy for mental disorders.