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analyzing reports of adverse drug reactions (ADRs) coming
from all parts of the Philippines. The purpose of the Committee
is NOT to criticize or castigate the prescribers. Neither
does it aim to stop usage of a drug in the market. Its primary
goal is to optimize the usage of pharmaceutical products
and promote rational prescribing. How? By collating reports
of suspected adverse drug reactions, a hypothesis can be
generated and the drug further studied to quantify the true
probability of its ADR. It also allows estimation of other
factors that could explain, confound or precipitate the
ADR. This will eventually lead to valuable information on
how to use the drug optimally and properly. It will also
decrease drug cost because the drug is chosen well taking
into consideration the profile of the patient, the contribution
of the disease to outcome and the influence of the other
drugs to its safety and efficacy.
BACKGROUND OF PHARMACOVIGILANCE
The early 70s saw the inception of pharmacovigilance from
the unfortunate Thalidomide accident which caused varied
limb to neurologic defects among offsprings of mothers who
took the drug during their pregnancies. It was a harsh and
sad reminder that safety with drug use must be established
as diligently as we try to prove its efficacy. However,
unlike efficacy which can be tested using a comparator drug
and clinical outcomes, safety is a function of the time
and number of users. Moreover, there is no comparator since
one does not entirely know what side effects the drug can
cause. Instead, what is available are bacground incidents
of the side effects.Recently, development in genetics and
toxicogenetics has also uncovered the different ways that
patients metabolize drugs causing different likelihood of
idiosyncratic drug reactions.
The longer we use a particular drug,
the greater likelihood of witnessing its adverse effects
and uncovering its secondary indications and benefits. Aspirin-now
an anti-platelet on top of its analgesic and antipyretic
effect, cimetidine-a potential immunostimulant and COX inhibitors
for Alzheimer are just some of examples of drug indications
not originally included in the initial package inserts.
On the other hand, sudden cardiac
arrest from the interaction of non sedating antihistamine,
astemizole with the macrolide antibiotics, anemia from nifedipine,
aplastic anemia from chloramphenicol are examples of unpredictable
adverse effects which became apparent only during the marketing
phrase of the drugs.
The Thalidomide accident also taught
pharmacologists and policy makers the ineffectual consequences
of banning ,withdrawing or prolonging registration of a
drug from the market. First, banning a drug can only shift
prescribing to another drug which may be more harmful that
the banned drug. Second, hypertensive patients in Europe
were already enjoying the beneficial effects of betablockers
much earlier than Americans due to the delay of approval
for marketing by the FDA. More importantly, drugs are limited
resources whose development can run for 5 to 10 years consuming
substantial amount of money and time. It is a waste of resources
if a drug ‘s existence is terminated without looking
at other factors that may have contributed to its adverse
effects. Efficacy should always be balanced by the safety
of the drug choice. Let us protect these resources. Lastly,
there is no safe drug, only unsafe physicians. These are
the realities that paved the way to the birth of Pharmacoepidemiology
and Pharmacovigilance, disciplines which make use of the
investigative tools of epidemiology to explain adverse drug
reactions.
We now challenge all prescribers--
PLEASE REPORT REPORT REPORT all suspected adverse drug reactions
to help optimize the use of pharmaceutical products.Morevoer,
local data which is more relevant to the Filipino patients
can customize therapeutic guidelines. Finally, although
drug treatment for a disease may be the same across races,
health seeking behaviors, patient's compliance, demography
and the health delivery systems which can affect clinical
outcomes can be very different. |
