MACROLIDES AND PHOSPHODIESTERASE TYPE-5 INHIBITORS - TADALAFIL

Erythromycin and clarithromycin (and therefore probably telithromycin) are pre- dicted to raise tadalafil levels by inhibiting its metabolism by CYP3A4. This effect has been seen with other inhibitors of CYP3A4 (up to 4-fold rise with ketoconazole). Other macrolides have less effect on CYP3A4, see macrolides, and therefore seem less likely to interact.
The adverse effects of tadalafil may be increased in some patients. The manufac- turers advise caution.