dextromethorphan hydrobromide + pseudoephedrine hydrochloride + triprolidine hydrochloride: clinical use

Prescribing considerations

• Confirm that dry cough and congestion are both present and that all three components are appropriate.
• Assess persistent or chronic cough, asthma, excessive secretions or suspected respiratory failure rather than suppressing cough empirically.
• Review cardiovascular, renal, hepatic, ophthalmic, endocrine and urinary history.
• Consider misuse, dependence and withdrawal risk.
• Review serotonergic, sympathomimetic, sedative and CYP2D6-inhibiting medicines.

Contraindications and cautions

• Age under 12 years
• Hypersensitivity to an active ingredient or excipient
• Cardiovascular disease, severe or uncontrolled hypertension
• Diabetes mellitus, phaeochromocytoma or hyperthyroidism
• Closed-angle glaucoma
• Severe acute or chronic kidney disease or renal failure
• Respiratory failure or risk of respiratory failure
• Concurrent sympathomimetic decongestants, beta-blockers, SSRIs or MAOIs

Monitoring

• Clinical response and persistent or worsening respiratory symptoms
• Drowsiness, impaired cognition and anticholinergic effects
• Blood pressure, pulse and cardiovascular symptoms where relevant
• Features suggesting serotonin syndrome
• Severe skin reactions, ischaemic colitis, visual symptoms or neurological features of PRES/RCVS
• Escalating use, dependence or withdrawal symptoms

Clinical pharmacology

Triprolidine is a competitive H1-receptor antagonist with mild central depressant and anticholinergic effects. Pseudoephedrine has direct and indirect sympathomimetic activity. Dextromethorphan suppresses the medullary cough centre and undergoes variable CYP2D6 metabolism to active dextrorphan.

Formulation and product differences

• The selected product is a clear red oral liquid supplied with a double-ended measuring spoon.
• It contains sucrose, sorbitol and ethanol, with implications for sugar intolerance, hereditary fructose intolerance and pregnancy or breastfeeding.
• It also contains sodium benzoate, methyl hydroxybenzoate and Ponceau 4R; the latter two may cause allergic reactions.
• Similarly branded products may contain different active ingredients, so check the exact pack and formulation.