8 Mrs. Dilworth Faints

By the third hospital day, Mrs. Dilworth is receiving —

aztreonam (an antibiotic)
clindamycin phosphate (an antibiotic)
ondansetron (an anti-emetic/anti-nausea drug),
risperidone (an anti-psychotic drug given to this patient because of her history of bipolar disease ),
and
loratadine (for itching).

The patient has a fainting episode and an EKG is ordered. Heart beat irregularities are noted on the EKG.  The patient team wonders whether a drug interaction might be causing the heart beat irregularity.