Health professionals have been urged to consider the impact fasting diets could have on their patients’ medications.
In a letter to the MJA pharmacists from Austin Health in Melbourne write that the popular 5:2 diet, where calorie consumption is restricted for 5 days a week, could be having an effect on medications.
For some medications fasting could significantly affect absorption or increase gastrointestinal or other adverse effects when taken on an empty stomach.
For example when fasting the bioavailability of telaprevir for chronic hepatitis C was 27% of that when taken with a standard meal.
While the absorption of warfarin was not affected by fasting, it was possible that an altered diet (particularly diets high in vitamin K foods) could lead to volatility in the international normalised ratio.
Glibenclamide, glimepiride and insulin also carried a high risk of hypoglycaemia if normal doses were taken while fasting, they wrote.
“Information regarding potential clinical significance of the diet may be evaluated via the full product information for individual medications and through community and hospital pharmacies”, they advised.