MACROLIDES AND TOLTERODINE
The manufacturers of tolterodine warn that potent CYP3A4 inhibitors (they name clarithromycin and erythromycin) increase the risk of tolterodine toxicity. Other macrolides may also interact, see macrolides.
Based on the interactions of other CYP3A4 inhibitors with tolterodine it may be prudent to monitor for adverse effects and to bear in mind the possibility of an interaction if antimuscarinic effects (dry mouth, constipation, drowsiness) are increased. However, note that the UK manufacturers advise avoiding concurrent use, whereas the US manufacturers suggest reducing the tolterodine dose to 1 mg twice daily.
Based on the interactions of other CYP3A4 inhibitors with tolterodine it may be prudent to monitor for adverse effects and to bear in mind the possibility of an interaction if antimuscarinic effects (dry mouth, constipation, drowsiness) are increased. However, note that the UK manufacturers advise avoiding concurrent use, whereas the US manufacturers suggest reducing the tolterodine dose to 1 mg twice daily.