Incidence and Possible Causes of Prescribing Potentially Hazardous/contraindicated Drug Combinations in General Practice

Yen-Fu Chen1, Anthony J Avery2, Karen E Neil2, Christine Johnson3, Michael E Dewey1, Ivan H Stockley. 1Trent Institute for Health Services Research and 2Division of General Practice, University of Nottingham; 3Beeston Primary Care Research Group, Manor Surgery, Nottingham, UK

Corresponding author: Dr Yen-Fu Chen

Current address: Primary Care Clinical Science, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom

Phone: +44 121 4146095 Fax: +44 121 4147878 E-mail:

List of drug combinations screened in this study

Numbers in parentheses are corresponding sections in the British National Formulary No. 39, March 2000.

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Amiodarone

/ Thyroid hormones (6.2.1): Thyroxine (Levothyroxine), Liothyronine sodium
/

Sotalol

Azapropazone

/ Oral anticoagulants
(2.8.2): Nicoumalone (Acenocoumarol), Warfarin Sodium, Phenindione

Betahistine

/ Antihistamines
(3.4.1): Acrivastine, Azatadine, Brompheniramine, Cetirizine, Chlorpheniramine, Clemastine, Cyproheptadine, Fexofenadine, Hydroxyzine, Loratadine, Mizolastine, Promethazine, Terfenadine, Trimeprazine
/

Cinnarizine

/

Cyclizine [chloride, lactate, tartrate]

Dimenhydrinate

Diphenhydramine

Ketotifen

Cabergoline

/

Chlorpromazine

/ Methotrimeprazine (Levomepromazine) [hydrochloride, maleate]
/

Promazine

Thioridazine

Fluphenazine [decanoate, enanthate, hydrochloride]
Trifluoperazine
Benperidol
Droperidol
Haloperidol

Flupenthixol

Zuclopenthixol [acetate, decanoate, dihydrochloride]
Metoclopramide
Domperidone
Cisapride / Ketoconazole*
Fluconazole
Itraconazole
Erythromycin**
Clarithromycin
Terfenadine
Amiodarone
Amitriptyline HCl
Chlorpromazine
Thioridazine
Levodopa / Isocarboxazid
Phenelzine
Tranylcypromine
Dexamphetamine / Haloperidol
Isocarboxazid
Phenelzine
Tranylcypromine

Ergotamine

/ Nitrates (2.6.1): Glyceryl trinitrate, Isosorbide dinitrate, Isosorbide mononitrate
Erythromycin**
Clarithromycin
Indoramin / Isocarboxazid
Phenelzine
Tranylcypromine
Itraconazole / Simvastatin
Adrenaline*** /

Amitriptyline HCl

Clomipramine
Dothiepin
Doxepin [not HCl]
Imipramine HCl
Lofepramine
Nortriptyline
Trimipramine
Methocarbamol / Distigmine
Pyridostigmine bromide
Methotrimeprazine (Levomepromazine) [hydrochloride, maleate] / Tranylcypromine
Methyldopa / Lithium salts
Methylphenidate
/ Isocarboxazid
Phenelzine
Tranylcypromine

Citalopram [hydrobromide, hydrochloride]

/ Monoamine-oxidase inhibitors (4.3.2): Isocarboxazid, Phenelzine, Tranylcypromine, Moclobemide
Fluoxetine / Monoamine-oxidase inhibitors (4.3.2): Isocarboxazid, Phenelzine, Tranylcypromine, Moclobemide
Fluvoxamine / Monoamine-oxidase inhibitors (4.3.2)
Paroxetine / Monoamine-oxidase inhibitors (4.3.2)
Sertraline / Monoamine-oxidase inhibitors (4.3.2)
Nefopam /

Isocarboxazid

Phenelzine
Tranylcypromine
Pethidine / Isocarboxazid
Phenelzine
Tranylcypromine
Pimozide / Chlorpromazine
Haloperidol
Thioridazine
Disopyramide
Amiodarone
Sotalol
Terfenadine
Amitriptyline HCl
Clomipramine
Dothiepin
Doxepin [not HCl]
Imipramine HCl
Lofepramine
Nortriptyline
Trimipramine
Bumetanide
Frusemide
Torasemide
Bendrofluazide
Chlorothiazide
Chlorthalidone
Clopamide
Cyclopenthiazide
Hydrochlorothiazide
Hydroflumethiazide
Indapamide
Mefruside
Metolazone
Polythiazide
Xipamide
Piperazine / Antiepileptics (4.8): Carbamazepine, Clobazam, Clonazepam, Ethosuximide, Gabapentin, Lamotrigine, Phenobarbitone, Phenytoin, Primidone, Sodium valproate, Tiagabine, Topiramate, Vigabatrin
Pseudoephedrine / Isocarboxazid
Phenelzine
Tranylcypromine
Pyrazinamide / Probenecid
Allopurinol
Quinine [bisulphate, dihydrochloride, hydrochloride, sulphate] / Cisapride
Reboxetine / Isocarboxazid
Phenelzine
Tranylcypromine
Repaglinide /

Erythromycin**

Fluconazole
Itraconazole
Ketoconazole*
Phenytoin
Rifampicin

Rizatriptan

/ Monoamine-oxidase inhibitors (4.3.2)
/ Nitrates (2.6.1): Glyceryl trinitrate, Isosorbide dinitrate, Isosorbide mononitrate
Sumatriptan

Sildenafil

/ Nitrates (2.6.1)
Sumatriptan / Ergotamine
Lithium salts
/ Nitrates (2.6.1)
Monoamine-oxidase inhibitors (4.3.2)
Terfenadine / Fluvoxamine
Nefazodone
Cisapride
Erythromycin**
Clarithromycin
Ketoconazole*
Itraconazole
Disopyramide
Amiodarone
Amitriptyline HCl
Clomipramine
Dothiepin
Doxepin [not HCl]
Imipramine HCl
Lofepramine
Nortriptyline
Trimipramine
Tramadol / Isocarboxazid
Phenelzine
Tranylcypromine
Venlafaxine / Isocarboxazid
Phenelzine
Tranylcypromine
Isocarboxazid / Phenelzine
Tranylcypromine
Moclobemide
Phenelzine / Tranylcypromine
Moclobemide
Tranylcypromine / Moclobemide
Bronchodilators (3.1) /

Nadolol

Oxprenolol
Pindolol
Propranolol
Sotalol
Timolol
Carteolol
Levobunolol

*Excluding cream and shampoo; **Excluding gel and topical solution; ***Excluding cream

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