Drugs that prolong QT interval

There is a very rare theoretical risk of abnormal heart rhythm if some medications are taken at the same time - see table below.

Antibiotics, antifungals
Azithromycin
Clarithromycin
Erythromycin
Fluconazole
Itraconazole
Ketoconazole
Antidepressants
Escitalopram
Citalopram
Clomipramine
Lithium
Sertraline
Venlafaxine
Antipsychotics
Amisulpride
Chlorpromazine
Haloperidol
Paliperidone
Pimozide
Risperidone
Zuclopenthixol
Diuretics, antihypertensives
Bumetanide
Diltiazem
Furosemide
Hydroflumethiazide
Indapamide
Metolazone
Chlorothiazide
Ranolazine
Sotalol
Torasemide
Heart rhythm drugs
Antihistamines
Hydroxyzine
Mizolastine
Triamcinolone
Others
Tolterodine (overactive bladder)
Bosutinib (hepatitis B)
Domperidone, ondansetron (anti-sickness)
Steroids
Methadone
HIV drugs
Cancer drugs
MS drugs
Parkinson's medication
Sildenafil, vardenafil
Mefloquine (Lariam)
Quinine
Bleeding disorder drugs

Further information: NHS - Long QT syndrome