Introduction
Medical treatment represents the most commonly used treatment modalities
in the world but adverse drug reactions (ADRs) from their usage pose a
great limitation. Adverse drug reactions (ADRs) are an important cause
of hospital admission, morbidity and mortality in hospitalised patients
[1]. Prevalence of ADR-related hospitalisations in developed and
developing countries reported as 6.3 % (3.3-11.0) and 5.5 %
(1.1-16.9), respectively, and the majority of the ADRs are preventable
[2]. ADRs have been reported as a significant cause of deaths among
hospitalised patients. The economic burden resulting from adverse drug
reactions among hospitalised patients is enormous, requiring between
billion United State Dollars ($30 billion) annually in the US [4].
In the Western world, the incidence of adverse reaction reactions varies
between 3.5% and 19.2% [5,6], while the incidence of 5.5% was
reported in Saudi Arabia [7]. In South Africa, the incidence of ADRs
was reported as 6.3% [8]. Adverse drug reactions studies in Nigeria
are rare and where available are retrospective [9], or from
randomized controlled clinical trials [10,11]. Adverse drug reaction
rates vary depending on the methods of ADRs detection employed in
different studies. Medical record review in conjunction with patient
interview yield higher ADR admission rates compared with medical record
review alone.
Adverse drug reactions reporting through pharmacovigilance have been
difficult in Nigeria and most studies have reported a low rate of
reporting [12-15]. Particularly, intense follow up of patients in
order to assess any adverse reaction occurring during the hospital stay
is rare. Our literature search did not reveal and to our knowledge this
is the first prospective cohort studies on adverse drug reactions in
in-patients spanning a period of one year in Nigeria. Aim of the study
is an intensive monitoring of medical patients for ADRs to assess
prevalence, incidence, risk factors, preventability and fatality of ADRs
leading to hospital admission or occurring in the hospital.