Bromhexine

Bromhexine is an oral mucolytic used for cough with viscous sputum in acute and chronic respiratory disease. Evidence of clinical benefit is weak. It is partly converted to ambroxol.

Classification. Mucolytic, secretolytic.

Mechanism. Depolymerises mucopolysaccharide fibres and stimulates serous secretion, lowering sputum viscosity and aiding ciliary clearance.

Pharmacokinetics. Well absorbed orally with extensive first-pass metabolism (bioavailability about 20%). The main active metabolite is ambroxol. Terminal half-life 12 to 16 hours. Renal excretion of metabolites.

Alternative, productive cough, adults and children over 14 years. 8 to 16 mg three times daily. Maximum 48 mg daily.

Children. 6 to 14 years: 8 mg three times daily. 2 to 5 years: 4 mg three times daily. Under 2 years: not advised.

Duration. Up to 7 days in acute illness. Reassess if symptoms persist.

Emergency and specialist use. None. Loading and titration do not apply.

Contraindications. Hypersensitivity, gastric or duodenal ulcer (caution), rare hereditary fructose intolerance in some syrups.

Serious adverse effects. Severe cutaneous reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), anaphylaxis, bronchospasm.

Common adverse effects. Nausea, dyspepsia, diarrhoea, headache, rash.

Interactions. Raises lung tissue levels of amoxicillin, cefuroxime, erythromycin and doxycycline. Cough suppressants lead to secretion accumulation.

Common prescribing errors. Prescribing with a cough suppressant. Continuing in the presence of a rash.

Special groups.

• Pregnancy: avoid in the first trimester; limited data. Breastfeeding: avoid.

• Older adults: no adjustment.

• Kidney impairment: reduce the dose or lengthen the interval in severe impairment, because metabolites accumulate. Liver impairment: reduce the dose or lengthen the interval in severe impairment.

• East Africa: commonly sold over the counter in combination syrups. Cough over 2 weeks requires tuberculosis testing.

Formulations. Tablets 8 mg, syrup 4 mg/5 mL, oral drops.

Administration. Give after meals with water.

Baseline. Cough duration and red flags, history of ulcer or skin reactions.

Monitoring. Sputum, cough and skin.

Stop and reduce rules. Stop at the first skin or mucosal eruption. Stop if no benefit after 7 days. Therapeutic drug monitoring is not used.

Referral and escalation. Refer for cough over 2 weeks, haemoptysis, breathlessness or severe skin reaction.