levomenthol + liquorice liquid extract + squill tincture: clinical use

Prescribing considerations

• Confirm a productive cough or sore throat requiring symptomatic relief.
• Review cardiac history, diuretics and carbenoxolone.
• Consider sugar and ethanol content and potential delayed allergy from parahydroxybenzoates.
• Investigate persistent, worsening or red-flag coughs.

Contraindications and cautions

• Hypersensitivity to any ingredient
• Any cardiac disorder
• Hereditary fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency

Monitoring

• Routine laboratory monitoring is not specified.
• If toxicity, excessive ingestion or an interaction is suspected, assess electrolytes and cardiac rhythm.
• Consider sodium and potassium disturbance with weakness, confusion, fluid retention or arrhythmia.

Clinical pharmacology

Squill acts as a reflex expectorant through gastric mucosal irritation. Liquorice is a demulcent and mild expectorant but can promote sodium retention and potassium loss. Levomenthol has cooling and local analgesic effects; absorbed menthol is eliminated as glucuronide conjugates.

Formulation and product differences

• The selected product information covers Covonia Chesty Cough Mixture Mentholated and Covonia Mucus Cough Oral Solution.
• The oral solution contains sucrose, glucose, ethanol, peppermint oil, anise oil, capsicum tincture and parahydroxybenzoate preservatives.
• It is described as essentially sodium-free despite liquorice's potential effect on sodium and water retention.