Adverse drug reaction assessment by health care providers: safety patient strategy

  • Elisangela da Costa Lima


Reporting Adverse Drug Reactions (ADRs) is an important component for quality of care
in hospitals, especially for accreditation programs1,2 since ADR are plainly implicated in patient safety
incident conception3. The manipulation and administration of medicines are a common factor for
adverse event discussion. Nevertheless, the ADR avoidability assessment tool may have a relevant role
for prevention of severe events in hospitals. This editorial will highlight factors contribute to the ADR
assessment debate in Brazilian clinical settings.
Unfortunately, limited and fragmented definitions about ADR notion may hamper its
identification and assessment at health services3
. ADRs has been defined as, “an appreciably harmful or
unpleasant reaction, resulting from an intervention related to the use of a medicinal product, which predicts
hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage
regimen, or withdrawal of the product”
.seems more precise, acceptable to pharmacologists and it has
been used in several studies5
. This concept is particularly interesting whereas that points the possibility of
occurrence of adverse reactions due to medication errors6
ADRs are classified in as type A and B reactions. Whilst type A (augmented) reactions are generally dose related and preventable (from the known pharmacology), type B (bizarre) reactions are
not dose related and unpredictable. Incidence and morbidity related type A reactions are high. On the
other hand, type B reactions are regarded to have mortality7
. This classification was expanded and detailed for more four types: C (chronic – some time after prolonged administration), D (delayed – sometime
after use of drug), E (end of treatment – some time after withdraw of drug) and F (failure unexpected of
. This collection of sub-categories is useful to make health professionals aware about the stages
leading up to ADRs.
ADR severity assessment ponders features related outcomes as (i) hospitalisation necessity
or prolongation of hospitalisation, persistence or significant disability, life-threatening and death5
. Severe
ADR report may require fast action for understanding the problem and consequently motivate a local
and/or global (regulatory authorities) intervention. Severe suspect ADR must be promptly recognize and
assessment by hospital pharmacists.
The causality assessment (i.e. relationship between a suspect medicine and ADR) helps
healthcare professionals to make decisions for upcoming therapy8
. Aspects as such strength of the
association and consistency of association, specificity, temporarity, biological gradient, plausibility,
coherence, experimental evidence and analogy (in some circumstances) have been suggested by
Bradford Hill9
more than 50 years ago. Expert assessor judgement, structured guidance as algorithms
and Bayesian statistical method are main ways used to causality assessment10. Scales and algorithms are
largely used, especially the Naranjo algorithm, however, there are some difficulties for applying guidance
for assessment8
All of the attributes above bring useful outlines to improve knowledge and clinical decision
regarding risk and benefit of treatment. However, for the advancement of safety culture, the avoidability
ADR assessment is pivotal for learning and preventing drugs related damage. A meta-analysis of ADR
avoidability showed approximately half of the reactions in adults may be avoided11.
There is no model for ADR avoidability assessments, but some scales grounded on treatment
selection or prescribing appropriateness12. Thinking about Avoidability in hospitals, even in the absence
of a suitable method is extremely important to improve health care since theses scales hold indicators
about possibility of reaction prevention such as (i) proper drug and (ii) dose, route and frequency of
administration suitable for patient`s and clinical condition, (iii) necessity of drug therapeutic monitory
or other laboratory test before or during drug use, (iv) history allergy or prior reaction to the drug, (v)
presence of drug-drug interaction, (vi) poor compliance or (vi) toxic serum drug level description13.


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How to Cite
Lima, E. da C. (2019). Adverse drug reaction assessment by health care providers: safety patient strategy. Revista Brasileira De Farmácia Hospitalar E Serviços De Saúde, 8(1). Retrieved from