Monitoring of Suspected Adverse Drug Reactions in Oncology Unit ...

International Journal of Research in Pharmaceutical and Biomedical Sciences ISSN: 2229-3701
Spontaneous reporting schemes
The thalidomide tragedy led to the institution, in many countries, of national schemes for voluntary
collection of adverse drug reaction reports, of which the UK Committee on Safety of Medicines adverse
reactions reporting scheme (outlined later) is one. Spontaneous reporting schemes cannot provide estimates
of risk because the true number of cases is invariably under estimated and the denominator is not known.
To be successful, reports should be made despite uncertainty about a causal relationship, irrespective of
whether or not the reaction is well recognized and regardless of other drugs having been giving
concurrently.
The development of pharmacist reporting of adverse drug reactions
[van Grootheest AC and de Jong-van den Berg, 2005; Major E, 2002; Davis S, et al, 1999; Lee A, et al,
1997]
Adverse reactions cause considerable morbidity and mortality and have a significant impact on health
care costs. Reports suggest that ADRs are responsible for 5% of all hospital admissions, with between 0.1
and 0.3% of hospital patients suffering fatal ADRs.
Following the thalidomide disaster in 1961, the Committee on Safety of Medicines was formed and the
‘Yellow Card Scheme’ was introduced in the UK in 1964. The scheme is a spontaneous reporting system
(based on yellow colored cards on which suspected ADRs are to be reported by health professionals) that
was developed to act as an early warning system for the identification of ADRs. It is intended to provide
information on the safely of a medicine throughout its lifespan. The success of the scheme is dependent
upon the vigilance of health professionals. The yellow card scheme solicits reports on all serious reactions
to all medicines licensed in the UK, as well as all reports on new ‘inverted black triangle’ medicines
regardless of the seriousness of the reaction. A black triangle status is assigned to all new medicines and are
described as being intensively monitored while this classification continues. The black triangle status
remains in place until the safety/efficacy ratio that was established in premarketing clinical trials is
adequately assessed. This period can be as short as two years but sometimes can last for upto five years.
The British ‘Yellow card system’ is one of the most successful spontaneous ADR reporting systems in
the world today. In the early 1990s, the number of reports received by the CSM was falling, particularly in
the hospital setting. A pilot study to evaluate the potential contribution of hospital pharmacists was
conducted in the Northern Region and showed a 45% overall increase in ADR reporting, with a 54%
increase in the reporting of serious drug reactions. Hospital pharmacists became recognized contributors to
the Yellow Card Scheme on 1 April 1997. In the first year of the scheme, hospital pharmacists reported a
higher proportion of serious ADRs then doctors did, but fewer for black triangle drugs. Reporting was
facilitated in hospitals where education on the scheme was provided, where there was a designated ADR
Pharmacist and where there was a written procedure for reporting ADRs.
From 1997 to 2002, the total number of reports submitted by pharmacists was 8,395, accounting for
8.5% of the total UK reports for that period. There is, however, still reluctance to reporting which needs to
be addressed through education and increasing awareness and ownership of the scheme.
Prevention of adverse drug reactions – role of the patient [van Grootheest K and de Jong-van den Berg
L, 2004; van Grootheest K et al, 2003; Egberts GPG, et al, 1996]
The prevention of ADRs should be a collective responsibility of the pharmaceutical industry, the doctor
and the patient. Patients themselves can play a significant role in the prevention of adverse reactions. In
particular, ensuring a high level of compliance with medication instructions can maximize therapeutic
effects and avoid or minimize the possible occurrence of potentially adverse reactions. Inadequate
compliance can lead to toxicity or treatment failure (this is clearly exemplified in anticonvulsant,
anticoagulant and immunosuppressive therapy) and consequently to increased treatment costs and / or
possible fatal outcome for the patient. Patients should also reject the belief that there is a “Pill for every ill”
and avoid indiscriminate self-medication and doctor hopping.
Causality assessment of adverse drug reactions
[Diemont WL, 2005; Merle L, et al, 2005; Brown SD Jr and Landry FJ, 2001]
The establishment of a causal relationship between specific drug and a clinical event is a fundamental
problem in pharmacovigilance. Firstly, ADRs frequently mimic other disease and secondly many of the
symptoms attributed to ADRs occur commonly in healthy individuals who are not taking any medication.
There is some evidence that patients themselves are capable of correctly distinguishing probable ADRs,
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