Products
Noscapine is commercially available in the form of lozenges, capsules, drops, as a syrup, and as suppositories. Except for Tussanil N, the drugs are combination products.
Structure and properties
The phthalideisoquinoline noscapine (C22H23NO7, Mr = 413.4 g/mol) is present in drugs as a free base or as noscapine hydrochloride monohydrate. Noscapine is a white crystalline powder or colorless crystals. The free base is insoluble in water, but the salt noscapine hydrochloride is readily soluble. It occurs naturally at 2-8% in opium from the immature capsules of the opium poppy.
Effects
Noscapine (ATC R05DA07) has cough-irritant properties. The mechanism of action is reported to be an attack at the cough center in the brainstem. We are unable to assess the actual efficacy. It should be noted that the available clinical studies are older and date from the 1950-80s. Modern registration studies are lacking. Noscapine, unlike opioids, appears to be relatively atoxic and not addictive. It is not sedating, analgesic, respiratory depressant, or euphoric.
Indications
For symptomatic treatment of irritable cough of various causes.
Contraindications
- Hypersensitivity
- Respiratory diseases with heavy mucus production
- Noscapine should be used in children under 2 years of age only if prescribed by a physician.
Full precautions can be found in the drug label. According to some sources, it is contraindicated during pregnancy.
Interactions
Concomitant administration of an expectorant or centrally depressant agents such as sedatives, sleeping pills, antidepressants, neuroleptics, opioids, or alcohol is not recommended. An interaction with the vitamin K antagonist warfarin has been reported in the literature, likely due to significant inhibition of CYP2C9 by noscapine. This inhibition could also be relevant for other CYP2C9 substrates, for example, phenprocoumon, phenytoin, or losartan.
Adverse effects
Possible adverse effects include headache, dizziness, nausea, skin reactions, and hypersensitivity reactions.
