Most medications prescribed in primary care contain animal derived products.

Are they suitable for vegetarians?

Dietary preferences are common in the general population. Influences such as religion, culture, economic status, environmental concern and personal preferences all play a part in the foods that people choose to consume. Most doctors are unaware that commonly prescribed drugs contain animal products and would be surprised that it matters. But most patients are not aware either and if they have a dietary preference it might impact the medicines they are willing to take also. 

Ingredients such as lactose, often extracted using bovine rennet, gelatine (sourced from cows, pigs and fish) and magnesium stearate (traditionally sourced from cows, pigs and sheep) might all be a concern for vegetarians, if they know about them. Last year, for example, a campaign to vaccinate children in Scotland against influenza was halted because Muslims community were concerned about pork gelatin within the vaccine.

Levels of animal products in many medications are likely to be minimal, somewhere between homeopathy and worth thinking about, but the authors say doctors still need to consider this when prescribing to avoid non-adherence to medications. 

To ascertain the scale of the problem, Dr. Kinesh Patel and Dr. Kate Tatham identified the 100 most commonly prescribed drugs in UK primary care in January 2013. Of these, 73 contained one or more of lactose, gelatin, or magnesium stearate. But they found that information on the origins of the contents was difficult to obtain, unclear, inconsistently reported, and sometimes incorrect.

"Our data suggest that it is likely that patients are unwittingly ingesting medications containing animal products with neither prescriber nor dispenser aware," they write.

They call for improved drug labeling, similar to those advised for food. However, they acknowledge it is unlikely that any labeling standard could address all dietary requirements, "and the ultimate solution would be to eliminate animal derived products where possible from medications."

They point out that lactose is already produced by some manufacturers without using rennet, magnesium stearate can be made chemically without animal ingredients and vegetarian capsules to replace gelatin are already available. But people who are against meat are likely to find chemical substitutes acceptable also.

"Although vegetarian friendly ingredients may be more expensive than those produced by traditional processes, the costs would diminish as production expanded and they would limit the exposure of patients to products they find unacceptable," they speculate. Though food preferences have historically caused costs to go up, as gluten-free and other trends show.