Drugs to avoid

Anyone with a condition affecting the heart that can cause sudden cardiac death needs to take extra care with medicines. All medicines – both those prescribed by your doctor and any you buy over the counter – must be checked, as some can increase the risk of sudden death.

For people with LQTS there are specific medications that can have a serious effect by further prolonging the QT interval. We give a list of these medicines below. This list includes drugs that can stimulate and irritate the heart by causing adrenaline-like effects. You must always check with your GP or cardiologist before taking any new medication, as this list will change with time.

In people with Brugada Syndrome the number and range of drugs that may make the condition worse is unknown and caution must be used. Antiarrhythmics, beta-blockers and some antidepressants are known to interact badly with it.

Drugs which people with Long QT Syndrome should avoid

Below is a list of the drugs that people with Long QT Syndrome should avoid.  A similar list can also be found by clicking here.

Neither of these lists should be considered exhaustive, and you should always check with your GP and pharmacist if your doctor prescribes any new drugs for you, as these lists may not be complete.

* = Drugs which are unlicensed, withdrawn or suspended in the UK market

A – Z List

Aclarubicin Anti-cancer
Adrenaline (Epinephrine) Stimulant
Ajmaline* Antiarrhythmic (Class 1)
Alfuzosin Alpha1-blocker
Almokalant* Antiarrhythmic (Class 3)
Amantidine Antimalarial
Amiodarone Antiarrhythmic (Class 3)
Amitriptyline Psychiatric drug – Tricyclic antidepressant
Amoxapine* Psychiatric drug – Tricyclic antidepressant
Amphetamine Stimulant
Amsacrine Anti-cancer
Arsenic trioxide Anti-cancer
Astemizole* Antihistamine
Atomoxetine Psychiatric drug – Other
Azelastine Antihistamine
Azimilide* Antiarrhythmic (Class 3)
Azithromycin Antibiotic – Macrolide
Bepridil* Anti-anginal / vasodilator
Bretylium Antiarrhythmic (Class 3)
Chloral hydrate Sedative
Chloroquine Antimalarial
Chlorpromazine Psychiatric drug – Phenothiazine
Cibenzoline* Antiarrhythmic (Class 1)
Cimetidine Histamine H₂ receptor antagonist
Ciprofloxacin Antibiotic – Quinolone
Cisapride* Serotonin agonist / antagonist
Citalopram Psychiatric drug – Other
Clarithromycin Antibiotic – Macrolide
Clobutinol* Other
Clomipramine Psychiatric drug – Tricyclic antidepressant
Clozapine Anti-psychotic
Cocaine Stimulant
Cold remedies May contain stimulant drugs – always to check the label
Cotrimoxazole Antibiotic – Antifungal
d-sotalol* Antiarrhythmic (Class 3)
Desipramine* Psychiatric drug – Tricyclic antidepressant
Dexmethylphenidate Stimulant
Dihydroquinidine* Antiarrhythmic (Class 1)
Diphenhydramine Antihistamine
Disopyramide Antiarrhythmic (Class 1)
Dobutamine Stimulant
Dofetilide* Antiarrhythmic (Class 3)
Dolasetron Serotonin agonist / antagonist
Domperidone Other
Dopamine Stimulant
Doxepin Psychiatric drug – Tricyclic antidepressant
Dronedarone* Antiarrhythmic (Class 3)
Droperidol* Psychiatric drug – Other
Ebastine* Antihistamine
Encainide* Antiarrhythmic (Class 1)
Ephedrine Stimulant
Ersentilide* Antiarrhythmic (Class 3)
Erythromycin Antibiotic – Macrolide
Felbamate* Anticonvulsant
Fenfluramine Stimulant
Flecainide Antiarrhythmic (Class 1)
Fluconazole Antibiotic – Antifungal
Fluoxetine Psychiatric drug – Other
Fluphenazine Psychiatric drug – Phenothiazine
Foscarnet (HIV) Antibiotics – Antiviral
Fosphenytoin (prodrug of Phenytoin) Anticonvulsant
Galantamine Inhibitor (dementia, Alzheimer’s)
Gatifloxacin* Antibiotic – Quinolone
Geldanamycin* Anti-cancer
Gemifloxacin* Antibiotic – Quinolone
Granisetron Serotonin agonist / antagonist
Grepafloxacin* Antibiotic – Quinolone
Halofantrine* Antimalarial
Haloperidol Psychiatric drug – Other
Hydroxyzine Antihistamine
Ibutilide* Antiarrhythmic (Class 3)
Imipramine Psychiatric drug – Tricyclic antidepressant
Indapamide Anti-hypertensive
Isoprenaline (Isoproterenol) Stimulant
Isradipine Anti-hypertensive
Itraconazole Antibiotic – Antifungal
Ketanserin* Serotonin agonist / antagonist
Ketoconazole Antibiotic – Antifungal
Levalbuterol Stimulant
Levofloxacin Antibiotic – Quinolone
Levomethadyl* Psychiatric drug – Other
Lidoflazine* Anti-anginal / vasodilator
Lithium Anti-mania
Maprotiline Psychiatric drug – Other
Memantine Alzheimers drug
Mesoridazine Psychiatric drug – Other
Metaproterenol Stimulant
Methadone Psychiatric drug – Other
Methylphenidate Stimulant
Mexiletine Antiarrhythmic (Class 1)
Midodrine Stimulant
Moexipril / Hydrochlorthiazide Anti-hypertensive
Moxifloxacin Antibiotic – Quinolone
Naratriptan Anti-migraine
Nicardipine Anti-hypertensive
Nifekalant* Antiarrhythmic (Class 3)
Norepinephrine (Noradrenaline) Stimulant
Nortriptyline Psychiatric drug – Tricyclic antidepressant
Octreotide Other
Ofloxacin Antibiotic – Quinolone
Ondansetron Serotonin agonist / antagonist
Organophosphates* Other
Paroxetine Anti-depressant
Pentamidine Antibiotic – Other
Perflutren lipid microspheres Other
Pericycline Psychiatric drug – Other
Phentermine Stimulant
Phenylephrine Stimulant
Phenylpropanolamine Stimulant
Pimozide Psychiatric drug – Other
Pirmenol* Antiarrhythmic (Class 1)
Prenylamine* Anti-anginal / vasodilator
Probucol Other
Procainamide Antiarrhythmic (Class 1)
Prochlorperazine Psychiatric drug – Phenothiazine
Propafenone Antiarrhythmic (Class 1)
Protriptyline* Psychiatric drug – Tricyclic antidepressant
Pseudoephidrine Stimulant
Quetiapine Psychiatric drug – Other
Quinidine* Antiarrhythmic (Class 1)
Quinine Antimalarial
Ranolazine Anti-anginal / vasodilator
Risperidone Psychiatric drug – Other
Ritodrine Stimulant
Roxithromycin* Antibiotic – Macrolide
Salbutamol (Albuterol) Stimulant
Salmeterol Stimulant
Sematilide* Antiarrhythmic (Class 3)
Sertindole Psychiatric drug – Other
Sertraline Anti-depressant
Sibutramine Stimulant
Solifenacin Other
Sotalol Antiarrhythmic (Class 3)
Sparfloxacin* Antibiotic – Quinolone
Spiramycin Antibiotic – Macrolide
Sumatriptan Anti-migraine
Sunitib Anti-cancer
Tacrolimus Anti-cancer
Tamoxifen Anti-cancer
Telithromycin Antibiotic – Macrolide
Terbutaline Stimulant
Terfenadine* Antihistamine
Terikalant* Antiarrhythmic (Class 3)
Terodiline* Anti-anginal / vasodilator
Thioridazine* Psychiatric drug – Phenothiazine
Tizanidine Other
Tolterodine Bladder antispasmodic
Trazodone Psychiatric drug – Other
Trifluoperazine Psychiatric drug – Phenothiazine
Trimethoprim sulfa (bactrim) Antibiotic – Other
Trimipramine Psychiatric drug – Tricyclic antidepressant
Vardenafil Anti-anginal / vasodilator
Vasopressin Other
Venlafaxine Psychiatric drug – Other
Voriconazole Antibiotic – Antifungal
Zimeldine* Psychiatric drug – Other
Ziprasidone Psychiatric drug – Other
Zolmitriptan Anti-migraine



Listed by type

Class 1: ajmaline*, cibenzoline*, dihydroquinidine*, disopyramide, encainide*, flecainide, mexiletine, pirmenol*, procainamide, propafenone quinidine*
Class 3: almokalant*, amiodarone, azimilide*, bretylium, dofetilide*, dronedarone*, d-sotalol*, ersentilide*, ibutilide*, nifekalant*, sematilide*, sotalol, terikalant*

bepridil*, lidoflazine*, prenylamine*, ranolazine, terodiline*, vardenafil


indapamide, isradipine, moexipril/hydrochlorthiazide, nicardipine

astemizole*, azelastine, diphenhydramine, ebastine*, hydroxyzine, terfenadine*

Serotonin agonists and antagonists
cisapride*, dolasetron, granisetron, ketanserin*, ondansetron

Macrolide antibiotics: azithromycin, clarithromycin, erythromycin, roxithromycin*, spiramycin, telithromycin
Quinolone antibiotics: ciprofloxacin, gatifloxacin*, gemifloxacin*, grepafloxacin*, levofloxacin, moxifloxacin, ofloxacin, sparfloxacin*
Antifungals: cotrimoxazole, fluconazole (caution with itraconazole), ketoconazole, voriconazole
Others: pentamidine, trimethoprim sulfa (bactrim)
Antiviral: foscarnet (HIV)

amantidine, chloroquine, halofantrine*, quinine

Psychiatric drugs
Tricyclic antidepressants: amitriptyline, amoxapine*, clomipramine, desipramine*, doxepin, imipramine, nortriptyline, protriptyline*, trimipramine
Phenothiazines: chlorpromazine, fluphenazine, prochlorperazine, thioridazine*, trifluoperazine
Others: atomoxetine, citalopram, clozapine, droperidol*, fluoxetine, haloperidol, levomethadyl*, lithium, maprotiline, mesoridazine, methadone, paroxetine, pericycline, pimozide, quetiapine, risperidone, sertindole, sertraline, trazodone, venlafaxine, zimeldine*, ziprasidone

felbamate*, fosphenytoin (prodrug of phenytoin)

naratriptan, sumatriptan, zolmitriptan

arsenic trioxide, geldanamycin*, sunitib, tacrolimus, tamoxifen

alfuzosin, chloral hydrate, clobutinol*, domperidone, galantamine, octreotide, organophosphates*, perflutren lipid microspheres, probucol, solifenacin, tizanidine, tolterodine, vasopressin

Stimulant drugs
Some cold remedies contain these drugs so it is important always to check the label.
adrenaline (epinephrine), amphetamine, cocaine, dexmethylphenidate, dobutamine, dopamine, ephedrine, fenfluramine, isoprenaline (isoproterenol), levalbuterol, metaproterenol, methylphenidate, midodrine, norepinephrine (noradrenaline), phentermine, phenylephrine, phenylpropanolamine, pseudoephidrine, ritodrine, salbutamol (albuterol), salmeterol, sibutramine, terbutaline