PHOLCODINE

Absorption

After oral administration of 60 mg of pholcodine, the Tmax and Cmax are reported to be 1.3 hours and 26.3 ng/ml. In the same administration, the AUC in plasma and saliva are reported to be 1.67 and 6.61 mg h/l respectively. The absorption of pholcodine is reported to represent approximately 88% of the administered dose.

Toxicity

Generally, pholcodine is significantly less toxic than codeine. Nonetheless, it is important to consider the significant depressive respiratory effect.

Chemical properties

Yellow Solid

The Uses of PHOLCODINE

Antitussive; an opioid cough suppressant. Controlled Substance.

The Uses of PHOLCODINE

antimalarial derivative of natural artemisinin

Indications

Pholcodine is indicated as a cough suppressant for the temporary relief of non-productive dry cough. It is stated to present a required label indication of "temporary relief of dry cough." Cough is the respiratory movement that occurs after an irritation signal is transmitted to the central nervous system and further stimulates the medulla oblongata. This stimulation causes a motor output that is sent through motoneurons to the respiratory muscles. A non-productive cough is a type of cough characterized by the absence of sputum, and it has a large inspiration that will cause continuous coughing.

Background

Pholcodine formula is 3-o-morpholinoethylmorphine and it is classified as an antitussive which is defined as an opioid cough suppressant. It belongs to the opioid family of compounds and it is widely used. Pholcodine activity is the suppression of unproductive cough and it also has a mild sedative effect with little or no analgesic effects. Pholcodine is not prescribed in the United States where it is classed as a Schedule I drug. It is categorized as Class B drug in the UK and officially taken out of the shelves in 2008. Pholcodine is not approved in Canada.

Definition

ChEBI: A morphinane alkaloid that is a derivative of morphine with a 2-morpholinoethyl group at the 3-position.

brand name

Ethnine Simplex (Purdue Frederick).

Pharmacokinetics

The therapeutic doses of pholcodine have been shown not to cause depression of respiration, CNS excitation or other side effects associated with narcotics. It is thought that the impact of pholcodine is selective on the cough center without affecting the respiratory center. Pholcodine is not euphorigenic, and thus, psychological dependence is unlikely. Clinical trials have not shown any evidence of addiction after prolonged administration of pholcodine. It is well reported that pholcodine presents a more considerable respiratory depression effect than codeine and it causes hypotension in the same degree than codeine. Some other noted impacts of pholcodine in preclinical trials are: 1) the induction of histamine release, 2) anti-histaminic effect, 3) anti-acetylcholinic action, 4) anti-convulsant action and 5) mild tranquilizing action.

Metabolism

The metabolism of pholcodine seems to be very slow and due to the elimination profile, it is thought that most of the administered dose undergoes metabolism. There is some evidence in preclinical trials that indicate that morphine is a minor metabolite of pholcodine and that it accounts for 1% of the administered dose.