Dextromethorphan Hydrobromide + Diphenhydramine + Levomenthol

Indications

Dextromethorphan Hydrobromide + Diphenhydramine + Levomenthol is used for: Dry irritating cough, this is indicated as an antitussive for the night time relief of persistent, dry, irritating cough, and aiding restful sleep.

Adult Dose

Oral Syrup Adults and children aged 12 years and over: 2 tsf at bedtime followed by 2 tsf every 6 hours Or 2 tsf 4 times a day. Do not take more than 4 doses (1 dose = 2 tsf) in 24 hours.

Child Dose

Oral Syrup Children12 years and over: 2 tsf at bedtime followed by 2 tsf every 6 hours Or 2 tsf 4 times a day. Do not take more than 4 doses (1 dose = 2 tsf) in 24 hours.

Renal Dose

Administration

Contra Indications

This medicine is contraindicated in individuals with known hypersensitivity to the product or any of its components. This medicine is contraindicated in individuals who are taking, or have taken, monoamine oxidase inhibitors within the preceding two weeks. The concomitant use of a dextromethorphan-containing product and monoamine oxidase inhibitors can occasionally result in symptoms such as hyperpyrexia, hallucinations, gross excitation or coma. Dextromethorphan, in common with other centrally acting antitussive agents, should not be given to subjects in, or at risk of developing respiratory failure. Not to be used in children under the age of 12 years.

Precautions

This product may cause drowsiness; if affected, individuals should not drive or operate machinery. Diphenhydramine should not be taken by individuals with narrow-angle glaucoma or symptomatic prostatic hypertrophy. Subjects with moderate to severe renal or hepatic dysfunction should exercise caution when using this product. Cases of dextromethorphan abuse have been reported. Caution is particularly recommended for adolescents and young adults as well as in patients with a history of drug abuse or psychoactive substances. Dextromethorphan is metabolised by hepatic cytochrome P450 2D6. The activity of this enzyme is genetically determined. About 10% of the general population are poor metabolisers of CYP2D6. Poor metabolisers and patients with concomitant use of CYP2D6 inhibitors may experience exaggerated and/or prolonged effects of dextromethorphan. Caution should therefore be exercised in patients who are slow metabolizers of CYP2D6 or use CYP2D6 inhibitors It is not known whether dextromethorphan or its metabolites are excreted in breast milk. Diphenhydramine is known to cross the placenta and has also been detected in breast milk. This medicine should therefore only be used when the potential benefit of treatment to the mother exceeds any possible hazards to the developing foetus or suckling infant.

Pregnancy-Lactation

Interactions

The concomitant use of a dextromethorphan-containing product and monoamine oxidase inhibitors can occasionally result in symptoms such as hyperpyrexia, hallucinations, gross excitation or coma.

Adverse Effects

Side effects of Dextromethorphan Hydrobromide + Diphenhydramine + Levomenthol : Diphenhydramine may cause: drowsiness; dizziness; gastrointestinal disturbance; dry mouth, nose and throat; difficulty in urination or blurred vision. Dextromethorphan: dizziness, nausea, vomiting, or gastro-intestinal disturbance may occur.

Mechanism of Action

Dextromethorphan Dextromethorphan is a non-opioid antitussive drug. It exerts its antitussive activity by acting on the cough centre in the medulla oblongata, raising the threshold for the cough reflex. A single oral dose of 10-20 mg dextromethorphan produces its antitussive action within 1 hour and lasts for at least 4 hours. Diphenhydramine Diphenhydramine possesses antitussive, antihistaminic, anticholinergic properties. Experiments have shown that the antitussive effect (resulting from an action on the brainstem) is discrete from its antihistaminic effect. The duration of activity of diphenhydramine is between 4 and 8 hours. Menthol has mild local anaesthetic and decongestant properties.