ascorbic acid + paracetamol + phenylephrine hydrochloride: clinical use

Prescribing considerations

• Confirm that no other paracetamol, sympathomimetic decongestant or multi-symptom cold remedy is being used.
• Assess cardiovascular, hepatic, renal, endocrine, ophthalmic and urinary risk factors.
• Consider alcohol dependence, malnutrition, sepsis and other glutathione-depleting states.
• The powder contains sucrose and sodium; consider diabetes, controlled-sodium diets and relevant hereditary carbohydrate-intolerance disorders.
• The selected product is intended for people aged 16 years or over.

Contraindications and cautions

• Hypersensitivity to an active ingredient or excipient
• Concomitant sympathomimetic decongestants
• Phaeochromocytoma
• Closed-angle glaucoma
• Prostatic enlargement
• Hepatic impairment or severe renal impairment
• Hypertension, hyperthyroidism, diabetes or heart disease
• Tricyclic antidepressants or beta blockers
• Current or recent monoamine oxidase inhibitor use
• Hereditary fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency

Monitoring

• Urgently assess paracetamol exposure and possible liver injury after any overdose, regardless of early symptoms.
• Assess blood pressure and heart rhythm if cardiovascular symptoms develop.
• Investigate suspected high-anion-gap metabolic acidosis promptly; urinary 5-oxoproline may help identify pyroglutamic acidosis.
• Review persistent or worsening symptoms, high fever, rash or persistent headache.

Clinical pharmacology

Paracetamol is absorbed from the gastrointestinal tract, metabolised in the liver and mainly excreted as glucuronide and sulphate conjugates. Oral phenylephrine has irregular absorption and substantial first-pass monoamine-oxidase metabolism. Excess ascorbic acid is eliminated in urine.

Formulation and product differences

• The selected licensed product is a lemon-flavoured powder for preparation as a hot oral drink.
• It contains sucrose and sodium as excipients of known effect.
• The active ingredients are not expected to cause sedation, although dizziness may impair driving.