• Antiarrhythmic drugs
  • Quinidine (Quinidex extentabs, Quinaglute, Cardioquin, Duraquin)
  • Procainamide (Pronestyl, Procan, Procan SR, Procanbid)
  • Disopyramide (Norpace)
  • Sotalol (Betapace)
  • Amiodarone (Cordarone)
  • Ibutilide (Corvert)
  • Dofetilide
  • Flecainide (Tambocor)^a
  • Mexiletine (Mexitil)^a
  • Tocainide (Tonocard)^a
• Calcium blockers for angina
  • Bepridil (Vascor)
• Psychiatric drugs
  • Phenothiazines [prochlorperazine (Compazine), thioridazine (Mellaril), chlorpromazine (Thorazine), fluphenazine (Prolixin), trifluoperazine (Stelazine), perphenazine (Etrafon, Trilafon), etc.]
  • Tricyclics [amitriptyline (Elavil), imipramine (Tofranil), maprotiline (Ludiomil), nortriptyline (Pamelor), protriptyline (Vivactil), amoxapine (Asendin),^a clomipramine (Anafranil),^a doxepin (Sinequan),^a etc.]
  • Haloperidol (Haldol)
  • Pimozide (ORAP)
  • Risperidone (Risperdal)
  • Thiothixene (Navane)
• Antibiotics
  • Azithromycin (Zithromax)
  • Chloroquine (Aralen)
  • Erythromycin (Akne-Mycin, E-Mycin, Ery-Tab, EryPed, PCE Dispertab, and others)
  • Fluconazole (Diflucan)
  • Halofantrine (Halfan)
  • Itraconazole (Sporanox)
  • Ketoconazole (Nizoral)
  • Pentamidine (Pentacarinat, Pentam, NebuPent)
  • Trimethoprim-sulfa (Septra, Bactrim)
• Antihistamines (especially with antifungals, such as ketoconazole)
  • Terfenadine (Seldane-D)
  • Astemizole (Hismanal)
  • Clemastine (Tavist)^a
  • Diphenhydramine (Benadryl)^a
• Antihyperlipidemics
  • Probucol (Lorelco)
• Toxins
  • Arsenic
  • Organophosphate insecticides
  • Liquid protein diets
• Anesthetics/antiasthmatics
  • Adrenaline/epinephrine
• Miscellaneous (and potentially risky)
  • Amantadine (Symmetrel)
  • Diuretics without potassium, and sometimes magnesium, supplementation, especially indapamide (Lozol)
  • Chloral hydrate
  • Cisapride (Propulsid) with ketoconazole, fluconazole, itraconazole, miconazole, erythromycin, troleandomycin, clarithromycin
  • Cocaine
  • Fludrocortisone (Florinef)
  • Ipecac
  • Tamoxifen (Nolvadex)
  • Terodiline (Mictrol, Micturin)

^a Unconfirmed or rarely reported cases of torsades de pointes ventricular tachycardia.