Prevalence of contraindicated medical conditions and use of precluded medication

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Pain Pract. 2006 Dec;6(4):265-72.

Prevalence of contraindicated medical conditions and use of

precluded medications in patients with painful neuropathic disorders

prescribed amitriptyline.

Gore M, Dukes E, Rowbotham D, Tai KS, DL.

Avalon Health Solutions, Inc., Philadelphia, Pennsylvania 19102,

USA.

Amitriptyline is a tricyclic antidepressant that is historically

indicated and used to manage depression. More recently, due to

clinical evidence demonstrating efficacy, it is often prescribed in

the management of painful neuropathic disorders (PNDs). However, the

amitriptyline label contains numerous preclusions

(contraindications, warnings/precautions, drug interactions). Our

objective was to measure the frequency of amitriptyline

prescriptions in PND patients using the U.K. General Practice

Research Database and assess whether any prescriptions were given to

patients with preclusions listed in the product label.

We identified a total of 13,546 patients (mean age 59 +/- 16.2

years; 66.7% female) who had a diagnosis of a PND and received > or

=1 prescription for amitriptyline between July 1998 and June 2001.

Nearly half (46.7%) of PND patients prescribed amitriptyline had >

or =1 preclusion for its use; 3.5% had > or =1 contraindication; 22%

had > or =1 warning/precaution; and 33% received > or =1 medication

with a potential for drug interactions with amitriptyline.

Preclusions were more likely in women than in men (48.3% vs. 43.4%,

P < 0.0001); their incidence increased with age (42.8%, 50.4%,

55.1%, and 52.3% among those ages <65, 65-74, 75-84, and 85+ years,

P < 0.0001), and the number of patients with preclusions was the

highest in the phantom limb pain group (67.4%) and lowest in the

atypical facial pain group (42.9%), P < 0.001. The average daily

amitriptyline doses (starting: 33.6 +/- 32.4 mg; maintenance: 42.1

+/- 39.9 mg) were low compared to those used for the treatment of

depression.

Results indicate that, in a significant number of cases, the

existence of preclusions did not prevent the prescribing of

amitriptyline. Our findings raise a potential concern about the way

this medication is being used. However, the clinical significance of

these data is, as yet, unclear. Although, in theory, adverse

outcomes may have been associated with this practice, we could not

confirm this with this database analysis.