Abstract:
Introduction: Adverse drug reactions (ADRs) are broadly divided into predictable (related to
pharmacological actions of the drug in otherwise normal individuals) and unpredictable reactions (related
to individual’s immunological response and, on occasion, to genetic differences in susceptible patients).
Drug allergy is a type of unpredictable reaction. ADRs should be differentiated from adverse drug events
(ADEs). ADEs extend beyond ADRs to include harm related to medication errors and drug/food
interactions. While knowledge of ADEs is important in efforts to improve patient safety, ADRs are the
primary focus of regulatory agencies and post-marketing surveillance.
Clinical case: We present a 73-year-old woman who was consulted in the Emergency Room and
admitted in the Internal Medicine - Geriatrics Department because of a sudden syncope at home, associated
with dyspnea at rest and high rhythm palpitations. Three months ago she was diagnosed with atrial fibrillation,
but she stopped the treatment a week before coming to ER. The paraclinical tests showed no heart anomalies so
it was decided to initiate the therapy with Propafenone. After 8 days the Propafenone is changed with
Amiodarone because the EKG showed left bundle branch block (LBBB) and the laboratory analy sis presented
high values of cardiac enzymes, but the patient had a worsening general condition, associating dyspnea with
nervousness, coughing and increased heart rate (Sc>2=80-82%, Pulse=130bpm). so she received oxygen therapy
and a beta-blocker. On the next day she presented an allergic rush spreaded all over her body and so she
received Hydrocortisone hemisuccinate, but her allergy persisted and even spreaded wider. We realized that
she developed this abnormal reaction to Amiodarone. Metoprolol and later to ail the administrated drugs, even
on antiallergic one. Afterwards she reacted pretty well on antihistaminic medication, vitamin C and calcium.
The paradox was that in absence of any medication the heart rate remained convenient.
Results: A study of 141 patients with suspected drug eruptions, including histological
assessment, found that 24% were in fact reactive rashes or had other causes, suggesting that drug
eruptions were overdiagnosed on clinical grounds alone. Of the confirmed drug-related eruptions.
39.8% were caused by antibiotics, 21.2% by anti-inflammatories, 7.6% by contrast media and
31.4% by others (oral antidiabetics, antimycotics, antipsychotics, anti-epileptics and others).
Conclusion: All drugs can cause an allergic reaction and despite the fact that allergic reaction
to Amiodarone is very rare (under 1%), it still can occurs and it has to be considered when one
presents immunological reaction to the treatment.
Description:
Internal Medicine-Geriatrics Department, Faculty of Medicine, “Gr. T. Popa” University of Medicine and Pharmacy, laşi, Romania
