A significant proportion of vegetarians and other patients with dietary preferences borne out of cultural/religious practices are unwittingly consuming animal gelatin in prescribed medicines, reveals research published online in Postgraduate Medical Journal.
The findings prompt the authors to call for more comprehensive labelling of drug content and for vegetarian alternatives to animal gelatin to be used in manufacture.
The active component of a medicine accounts for relatively little of the content; most is made up of "excipients," which include binders/fillers, disintegrants, lubricants, sweeteners, and coating agents.
Gelatin is a commonly used coating agent, but is also used as a thickener in liquid and semisolid medicines, particularly in generic (non-branded) medicines.
The researchers surveyed 500 patients being treated for urinary/urological disorders in Manchester, a culturally diverse city in the north west of England.
Previous research has shown that many specialist urology drugs contain gelatin, while roughly one in four Mancunians is of non-white ethnicity.
The researchers wanted to know about the prevalence of dietary restrictions; the willingness to take medicines containing animal content; the preparedness to ask about the content of drugs; and the proportion refusing to take drugs they knew contained ingredients derived from animals.
Two hundred patients stated they were not supposed to eat animal products. Over half (283; 56.5%) were taking medicines, 75 of whom were taking a total of 87 different drugs.
Most (88%; 176) of the 200 patients following a restricted diet said they would prefer to take medicines containing only vegetable products, only one in 10 said this didn't matter to them.
Among the 176 with a stated preference, more than half (100; just under 57%) said they would take a drug containing an animal product, if no other alternative was available. But the remainder (43%) said they would not knowingly do so.
Yet only one in five of those with a stated preference would have asked their doctor or pharmacist if the drug's content flouted their dietary requirements/beliefs. And half of the 49 men, who had been prescribed medicines containing gelatin, were taking these drugs in contravention of their stated dietary preference.
"We already know that doctors are fairly ignorant about the issue of excipients in medication," write the authors, who conclude that their findings pose ethical quandaries for the entire profession.
Around 10 million people were prescribed specialist urinary/urological drugs in 2009 in the UK, but this category of drugs accounts for only the 14th commonest class of prescription, they say.
"[Gelatin content] is almost certainly a much bigger issue for the 860 million non-urological preparations prescribed in the UK each year, whose excipient content is not easily identified," they caution.
Clearer content labelling, the adoption of a vegetarian symbol as is done for foodstuffs, and changes in the manufacturing process could all help patients make informed choices as well as promoting best practice in medical care, they suggest.