Side effects of mirabegron studied on ants as models

The overactive bladder syndrome (OAB) affects the quality of life. It is most often treated with anticholinergic drugs, but at the cost of many unwanted effects. In the last decade to date, mirabegron, an adrenergic receptor agonist drug used to relieve OAB has appeared in the pharmacopoeia. It works through a different mechanism than antimuscarinic drugs, with apparently fewer side effects. In the same way that we have examined the adverse effects of the anticholinergic oxybutynin on the ant Myrmica sabuleti used as a biological model, here we examine the side effects of mirabegron. Unlike oxybutynin, mirabegron had no adverse effect on ants, except that it increased their meat consumption, reduced their sugar water intake and decreased their general activity. No adaptation was observed for this last- mentioned effect, which may correspond to the tiredness reported in humans. The ants did not become dependent on the consumption of mirabegron, whose effect on general activity decreased very slowly and disappeared about 52 hours after weaning. Patients are advised to take mirabegron daily though its elimination half-life is 50 hours, and fatigue is one of the side effects of the treatment. In the event that patients under mirabegron medication show a decrease in activity over their treatment, it would be careful to space out the medication or to add an appropriate stimulant or to alternate mirabegron with an anticholinergic drug that does not affect the patient’s level of activity. The kind of antimuscarinic drug that could be used together with mirabegron, the respective dosage and the timing of each drug should be defined depending on their combined efficacy and side effects, and taking into account their elimination time.