Taste preference for cough syrups: a comparative study of three codeine-containing medications

Unpleasant taste is a common feature of cough syrups, particularly those containing codeine. An antitussive compound of codeine sulfate and chlorpheniramine maleate was formulated in a coated drug-resin complex, which prevents release of the active ingredients until they reach the stomach and small intestine. Thus patients do not taste the bitterness of the codeine. A three-way crossover taste test was conducted in 175 volunteers who tasted each of three cough syrups in random sequence, rated the taste of each, and ranked their preferences. The cough syrups used in the study were the aforementioned formulation (CM), promethazine hydrochloride with codeine (PH), and iodinated glycerol with codeine phosphate (IG). Tastes were rated on a scale from +2 (very good) to -2 (very poor). Mean rating scores for each product were 0.97 for CM, 0.14 for PH, and -1.5 for IG. Pairwise comparisons showed statistically significant differences between CM and PH (P less than 0.01) and CM and IG (P less than 0.001) but no significant difference between PH and IG. CM was ranked as most liked by 115 respondents and as least liked by 27 respondents. Reasons cited for this preference were its sweet rather than medicinal taste and its smooth, thick consistency. Bitterness was a common reason for the lack of preference for PH and IG. CM thus was shown to have greater user acceptability than either of the other two cough syrups tested.