In vitro, liraglutide has shown very low potential to be involved in pharmacokinetic interactions with other active substances related to cytochrome P450 (CYP) and plasma protein binding.
The small delay of gastric emptying with liraglutide may influence absorption of concomitantly administered oral medicinal products. Interaction studies did not show any clinically relevant delay of absorption and therefore no dose adjustment is required.
Interaction studies have been performed with 1.8 mg liraglutide. The effect on rate of gastric emptying was equivalent between liraglutide 1.8 mg and 3.0 mg, (paracetamol AUC0-300 min). Few patients treated with liraglutide reported at least one episode of severe diarrhoea. Diarrhoea may affect the absorption of concomitant oral medicinal products.
Warfarin and other coumarin derivatives: No interaction study has been performed. A clinically relevant interaction with active substances with poor solubility or narrow therapeutic index such as warfarin cannot be excluded. Upon initiation of liraglutide treatment in patients on warfarin or other coumarin derivatives, more frequent monitoring of International Normalised Ratio (INR) is recommended.
Paracetamol (Acetaminophen): Liraglutide did not change the overall exposure of paracetamol following a single dose of 1,000 mg. Paracetamol Cmax was decreased by 31% and median tmax was delayed up to 15 min. No dose adjustment for concomitant use of paracetamol is required.
Atorvastatin: Liraglutide did not change the overall exposure of atorvastatin following single dose administration of atorvastatin 40 mg. Therefore, no dose adjustment of atorvastatin is required when given with liraglutide. Atorvastatin Cmax was decreased by 38% and median tmax was delayed from 1 h to 3 h with liraglutide.
Griseofulvin: Liraglutide did not change the overall exposure of griseofulvin following administration of a single dose of griseofulvin 500 mg. Griseofulvin Cmax increased by 37% while median tmax did not change. Dose adjustments of griseofulvin and other compounds with low solubility and high permeability are not required.
Digoxin: A single dose administration of digoxin 1 mg with liraglutide resulted in a reduction of digoxin AUC by 16%; Cmax decreased by 31%. Digoxin median tmax was delayed from 1 h to 1.5 h. No dose adjustment of digoxin is required based on these results.
Lisinopril: A single dose administration of lisinopril 20 mg with liraglutide resulted in a reduction of lisinopril AUC by 15%; Cmax decreased by 27%. Lisinopril median tmax was delayed from 6 h to 8 h with liraglutide. No dose adjustment of lisinopril is required based on these results.
Oral contraceptives: Liraglutide lowered ethinylestradiol and levonorgestrel Cmax by 12% and 13%, respectively, following administration of a single dose of an oral contraceptive product. tmax was delayed by 1.5 h with liraglutide for both compounds. There was no clinically relevant effect on the overall exposure of either ethinylestradiol or levonorgestrel. The contraceptive effect is therefore anticipated to be unaffected when co-administered with liraglutide.
Paediatric population: Interaction studies have only been performed in adults.