Chimps in an open-air forested enclosure have spotted veterinarian Raven Jackson carrying a caddy packed with their morning's juice treats and frozen bananas. A half-dozen dark-haired chimpanzees crowd the wire metal gate and wait for her to dispense the goodies.
Codeine is a narcotic. It is a pain reliever and a cough suppressant. Promethazine is an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body. The combination of codeine and promethazine is used to treat cold or allergy symptoms such as runny nose, sneezing, and cough.
Antihistamines such as promethazine compete with histamine for one of the receptors for histamine (the H1 receptor) on cells; however, when antihistamines bind to the receptors they do not stimulate the cells. Instead, they prevent histamine from binding and stimulating the cells.Promethazine also blocks the action of acetylcholine, a neurotransmitter that nerves use to communicate with one another, on its receptors (anticholinergic effect), and this may explain its benefit in reducing the nausea of motion sickness.It is used as a sedative because it causes drowsiness as a side effect.ntihistamines such as promethazine compete with histamine for one of the receptors for histamine (the H1 receptor) on cells; however, when antihistamines bind to the receptors they do not stimulate the cells. Instead, they prevent histamine from binding and stimulating the cells.