Ergot
toxicity can develop rapidly in patients taking ergotamine or dihydroergotamine if they are given
erythromycin. However, in one case, the reaction occurred when
erythromycin was started 3 days after the last dose of dihydroergotamine. Other cases have been reported with
clarithromycin and josamycin.
Toxicity is also predicted to occur with midecamycin and
telithromycin.
The combination of
ergot derivatives and
macrolides that inhibit CYP3A4 is best avoided. Note that the
macrolides differ in their ability to inhibit CYP3A4, see
macrolides. No cases of
toxicity appear to have been described with
azithromycin,
dirithromycin, or spiramycin, and none would be expected.