QT prolonging drugs - for full listing of drugs to be avoided, please see https://crediblemeds.org/index.php/new-drug-list
List of drugs which may prolong QT interval and increase the risk of torsades de pointes tachycardia
Drugs to be avoided in patients with congenital long QT syndrome
Main target organ central nervous system
Antipsychotic drugs
chlorpromazine
haloperidol
thioridazine
mesoridazine
pimozide
other phentiazine derivates
other butyrophenone derivates
other piperidine derivates
Antidepressants
amitriptyline
doxepine
litium
prenylamine
methadone
Group includes some antiemetic & travel sickness drugs and drugs against vertigo.
Antiarrhythmic drugs
disopyramide
dofetilide
ibutilide
procainamide
quinidine
sotalol
amiodarone
flecainide
Antihistamines
difenhydramine
terfenadine
astemizole
combination drugs which contain pseudoephedrine
terfenadine
Antimicrobics
erythromycin
chlarithromycin
other macrolide antimicrobics at least when used simultaneously with antihistamines or amiodarone
halofantrine
sulfonamides
pentamidine
sparfloxacin
other fluorocinolones
sakinavir
Others
cholorocine
cisapride
sildenafile
tamoxifen
methadone
domperidone
droperidol
clobutinol
Drugs which may cause hypokalemia
several diuretics
corticosteroids
beta-2 adrenergic agonists