Treatment methods having reduced drug-related toxicity and methods of identifying the likelihood of patient harm from prescribed medications

A method for determining whether a patient has an increased risk of long QT syndrome or Torsades de Pointes by the method comprising the steps of:

• determining a patient specific score based on one or more of a plurality of risk variable values derived from at least one of a plurality of risk factors comprising:
• (a) the patient's sex;
• (b) the patient's age;
• (c) the patient's heart rhythm;
• (d) the patient's potassium level;
• (e) the patient's magnesium level;
• (f) the presence a diuretic in the patient;
• (g) the presence of an antiarrhythmic in the patient;
• (h) a drug-drug interaction coefficient (“DDIC”) for one or more drug therapeutics in the patient's treatment regimen;
• and
• (i) the patient's OTc interval, and
• combining the risk variable values, and
• comparing the patient specific score to a predetermined threshold value indicative of a greater than normal risk of long QT syndrome or Torsades de Pointes.

The method of claim 8, wherein the medication is selected from the group consisting of Albuterol, Alfuzosin, Amantadine, Amiodarone, Amitriptyline, Amphetamine, Arsenic trioxide, Astemizole, Atazanavir, Atomoxetine, Azithromycin, Bepridil, Chloral hydrate, Chloroquine, Chlorpromazine, Ciprofloxacin, Cisapride, Citalopram, Clarithromycin, Clomipramine, Clozapine, Cocaine, Desipramine, Dexmethylphenidate, Diphenhydramine, Diphenhydramine, Disopyramide, Dobutamine, Dofetilide, Dolasetron, Domperidone, Dopamine, Doxepin, Dronedarone, Droperidol, Ephedrine, Epinephrine, Erythromycin, Escitalopram, Escitalopram, Famotidine, Felbamate, Fenfluramine, Flecamide, Fluconazole, Fluoxetine, Foscarnet, Fosphenyloin, Galantamine, Gatifloxacin, Gemifloxacin, Granisetron, Halofantrine, Haloperidol, Ibutilide, Imipramine, Indapamide, Isoproterenol, Isoproterenol, Isradipine, Itraconazole, Ketoconazole, Lapatinib, Lapatinib, Levalbuterol, Levofloxacin, Levomethadyl, Lisdexamfetamine, Lithium, Mesoridazine, Metaproterenol, Methadone, Methylphenidate, Midodrine, Moexipril/HCTZ, Moxifloxacin, Nicardipine, Nilotinib, Norepinephrine, Nortriptyline, Octreotide, Ofloxacin, Ondansetron, Oxytocin, Paliperidone, Paroxetine, Pentamidine, Perflutren lipid microspheres, Phentermine, Phenylephrine, Phenylpropanolamine, Pimozide, Probucol, Procainamide, Protriptyline, Pseudoephedrine, Quetiapine, Quinidine, Ranolazine, Risperidone, Ritodrine, Ritonavir, Roxithromycin, Salmeterol, Sertindole, Sertraline, Sibutramine, Solifenacin, Sotalol, Sparfloxacin, Sunitinib, Tacrolimus, Tamoxifen, Telithromycin, Terbutaline, Terfenadine, Thioridazine, Tizanidine, Tolterodine, Trazodone, Trimethoprim-Sulfa, Trimipramine, Vandetanib, Vardenafil, Venlafaxine, Voriconazole, Ziprasidone, and a pharmaceutically acceptable salt thereof.

A method of treating a patient with a medication that is determined to increase the risk of long QT syndrome or Torsades de Pointes as a result of the drug-drug interaction coefficient (“DDIC”) for one or more drug therapeutics in the patient's treatment regimen, the method comprising the steps of:

• administering a first pharmaceutical composition to the patient, the pharmaceutical composition comprising a therapeutically effective amount of the medication or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier;
• determining whether the patient has an increased risk of developing long QT syndrome or Torsades de Pointes due to a patient-specific score that is indicative of an increased risk of developing long QT syndrome or Torsades de Pointes;
• and
• upon a determination that the patient has an increased risk of developing long QT syndrome or Torsades de Pointes, halting treatment of the patient with the pharmaceutical composition.