Carbocisteine (also spelled carbocysteine) is the active mucolytic agent. For example, in adult formulations: 5 g per 100 mL (i.e. a 5 % syrup).

– In formulations combining with antihistamines: e.g. Rhinathiol + Promethazine syrup includes carbocisteine + promethazine.

– Excipients include: sucrose, methyl parahydroxybenzoate (E218), ethanol (small amount), sodium hydroxide, caramel colour, flavouring (cinnamon/rum flavour) etc.

– For children: the “children / junior” syrup (2 %) may be dosed as 5 mL two or three times a day, depending on age. 

– Duration: generally short-term (for acute phases). Some labels caution not to exceed about 8-10 days in children. 

– Shake the bottle well before use. (Standard instruction for syrups; many leaflets include this) 

• Allergic reactions: rash, itching, other hypersensitivity responses 
•  Occasionally, very rare severe skin reactions (e.g. Stevens-Johnson syndrome) have been listed in leaflets as warnings for overdosage or hypersensitivity. 
•  Some sources mention possible gastrointestinal bleeding in rare cases. 

Typically in bottles (e.g. 125 mL, 200 mL, 250 mL) with measuring cup or spoon included. 

•  Protect from moisture and light. 
•  Keep out of reach of children. 
•  After use, some leaflets recommend wiping the bottle neck before closing to remove residual syrup. 

 Contraindicated in known hypersensitivity to carbocisteine or any excipient (e.g. parabens) 

•  Use caution in patients with gastric or duodenal ulcers (may aggravate) 
•  Avoid use of cough suppressants (antitussives) concurrently, as mucolytics rely on cough to expel loosened mucus 
•  In patients with liver disease, alcoholism, epilepsy, those at risk with alcohol, check ethanol content — the syrup contains small amount of ethanol (e.g. 0.2 g per 15 mL) in some formulations. 
•  Be careful with sodium load (e.g. 97 mg sodium per 15 mL in some formulations) in patients on sodium-restricted diets. 

 Use in pregnancy / lactation only with medical supervision, as safety data are limited. 

•  Monitor for signs of allergic reaction or worsening of respiratory condition.
•  Do not exceed recommended duration in children (often ≤ 8–10 days) unless advised by a physician. – Overdose may cause serious adverse reactions (skin blistering, mucosal bleeding) — seek medical help. 

Other mucolytic/expectorant syrups (e.g. generic carbocisteine syrups), or medications containing carbocisteine alone; in some settings, agents like N-acetylcysteine, ambroxol, guaifenesin, etc., might be used depending on local practice.

The UK licensed manufacturer is A. Nattermann & Cie GmbH, Cologne, Germany (for the Rhinathiol syrup 250 mg/5 mL) with licence holder Lexon (UK) Ltd.

In local markets (e.g. Ghana), “Rhinathiol Cough Junior Syrup” is marketed by local pharmacies (Scab Pharmacy) — active ingredient: carbocisteine.