Chemical formula: C₁₈H₂₃NO₃ Molecular mass: 301.38 g/mol PubChem compound: 5284543
Dihydrocodeine is a semisynthetic narcotic analgesic with a potency between morphine and codeine. It acts on opioid receptors in the brain to reduce the patient’s perception of pain and improve the psychological reaction to pain by reducing the associated anxiety.
Dihydrocodeine is a centrally-acting anti-tussive. Dihydrocodeine works on the cough centre to lessen the incidence and intensity of coughing fits. Dihydrocodeine inhibits troublesome, unproductive cough but does not impair the expectoration of bronchial mucus. The analgesic action of DHC may be helpful in patients with painful cough. Dihydrocodeine also exerts dose-dependent sedative effects.
The metabolism of dihydrocodeine shows important similarities with metabolism of codeine. Dihydrocodeine is also a substrate of the polymorphic enzyme CYP2D6. This enzyme catalyses the conversion of dihydrocodeine to dihydromorphine by the O-demethylation pathway.
The principal actions of therapeutic value of dihydrocodeine are analgesia and an antitussive effect (depression of the cough reflex by direct effect on the cough centre in the medulla). Antitussive effects may occur with doses lower than those usually required for analgesia.
Opiates may cause depression of the respiratory centre and thereby reduce its sensitivity to normal respiratory stimuli (CO2 partial pressure in the blood). Dihydrocodeine may produce respiratory depression by direct action on brain stem respiratory centres. It depresses the respiratory centre in a dose-dependent fashion.
Dihydrocodeine causes a reduction in motility associated with an increase in smooth muscle tone in the antrum of the stomach and duodenum. Digestion of food in the small intestine is delayed and propulsive contractions are decreased. Propulsive peristaltic waves in the colon are decreased, while tone is increased to the point of spasm resulting in constipation.
Dihydrocodeine is readily absorbed after oral administration, has a duration of action of 4 to 6 hours, is extensively metabolised in the liver and is excreted mainly via the kidney.
Metabolism of dihydrocodeine includes o-demethylation, n-demethylation and 6-keto reduction.
The biological availability of dihydrocodeine is three times higher than that of codeine. In comparative studies in healthy volunteers, 35% of the orally-applied dose of dihydrocodeine was eliminated in the urine in the course of 24 hours. After oral administration of dihydrocodeine, the highest concentration was found in the plasma after 1.7 hours. The elimination half-life was 4 hours.
Not applicable.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
