Introduction
Rational Use of Drugs is usually
linked with 5 Right, which include Right drug, Right patient, Right Dose, Right
time and Right Rout. But these five rights are lacking considerations like Cost
effectiveness, Safety and Toxicity.
WHO defines rational use of drugs as
“Patients receive medications appropriate to their clinical needs, in doses
that meet their own individual requirements, for an adequate period of time,
and at the lowest cost to them and their community.” (WHO, 1985)”.
In contrast to Rational use of drugs
words like Irrational use or Pathological use or Non-Rational use of drugs are used
interchangeably. “It is use of the drugs noncompliant with the rational use of
drugs” as defined above. According to
WHO more then 50 % of drug are in Irrational use in the world. And 50% of
patients take drugs inappropriately due to poor knowledge and guidance about
their drug.
Common types of Irrational use of Drug:
v Use of antibiotics for viral
infections
v Using high dose of drugs instead of
lowers dose
v Use of Antibiotic incase of undefined
Sensitivity to that antibiotic
v Wrong Rout for Drug delivery like IV
when oral Dose is effective, safe and possible.
v Poly Pharmacy
v Inappropriate self-administration
v Use of expensive drugs when low cost
safe and effective alternatives are available
Drawbacks of Irrational Use of Drugs
- v Morbidities and Mortalities associated with the Pathological use of drugs
- v Burdon on Health care system
- v Loss of Patient’s trust on health care system
- v Increased Antibiotic resistance due to inappropriate use of antibiotics
- v Waste of Resources
Steps in Rational Drug Prescribing
For appropriate follow steps must be
considered and they should be done with full concentrations, proper knowledge
and skills.
Diagnosis
Diagnosis is the first step in
rational prescribing. Poor diagnosis lead to pathological or irrational use of
drugs. If any concurrent diagnosis is made (secondary diagnosis) then the decision
of drugs selection should be base on secondary diagnosis as well (the first
priority being the primary diagnosis) i.e Patient with Hypertension and
Diabetes the choices of Different Anti-hypertensives are there but the most suitable
anti-hypertensives ACE inhibitors, Prevent Hypertension and Proteinuria caused
by Diabetes. It is general example, not applicable for all the patient, in
reality prescription selection is totally individualize and vary form patient
to patient.
Prognosis
Diagnosis is followed by prognosis,
which show the condition or status of disease. Poor prognosis lead to poor
selection of drugs or low dose of drugs and inappropriate combinations. Just
like advance Stage of disease may require different drugs or the same drugs
with different dose strengths.
Goal of Therap
Goal of therapy May include
- · Eradication of disease (cancer, infection)
- · Prolong prevention just like (HTN, Diabetes Mellitus)
- · Prophylaxis of a disease in epidemic and endemic areas
- · For Diagnostic purpose
- · Replacing deficiencies
In all of the above conditions Drug
selection depends just like you may go for different antibiotic for bacterial prophylaxis
as compare to the treatment of that specific condition.
Treatment Selection
Treatment Selection totally depends
upon the knowledge of the pharmacodynamics a pharmacokinetics and toxicological
properties of a drugs. Treatment selection may include non-pharmacological
interventions. Just like Patient with Hypertension (HTN) may have various treatment
options for i.e Change in the life style habits, Drugs (Various classed) and Exercise
etc.
Monitoring
Monitoring involves follow ups after
treatment is selected. It checks the patient status, effectiveness of drugs for
that condition, prevention of side effects and adverse effects etc. if patient
is not responding to the therapy modification may be brought like change in the
dose, change in the drugs selected or withdrawal of the drugs. Different
approaches are made just like subjective approaches to find that status of
condition like (reduction in pain or improved quality of life) and objective
approach in condition which are measurable (reduction of infection, changes in
bio-markers of disease).
Factors Influencing Drug selection
Pharmacokinetic factors
Absorption, distribution, Metabolism
and Excretion (ADME) of a drug play immense role in selection. Vancomycin which
is not absorbed through blood brain barriers cant be use in meningitis.
Similarly metabolism also affect the selection of drugs pravastatin and
simvastatin , prioritize pravastatin just because of low chances of drug
interactions due to metabolic enzymes. Elimination also affect the drug
selection or demands in changes in dose i.e in Kidney diseases or hepatic impaired
conditions.
Pharmacodynamics Factors
Pharmacodynamics factors include
Specificity of a drugs (COX2 selective drugs in Ulcer patients), affinity for
other receptors and other sites other then biological target (ACE inhibitors
and ARBs reduction in hypertension and Kidney tubules preventing proteinuria),
ADRs (Aspirin restricted use in asthma).
Prescriber Factors
Prescriber factors include thing like
proper knowledge of drugs, proper
environment for prescriber, Optimum work load etc. Poor knowledge background of
prescriber may exaggerate the current condition of the patient by poor
diagnosis, prognosis, drugs selection and improper monitoring or follow ups.
Patient Factors
Patient factors include things like Propensity
of drugs reactions (allergies to various classes), genetic factors in
metabolism (i.e slow and fast acetylators), compliance to the treatment plan.
No matter how best are the diagnosis and drugs selection made but if the
patient is not compliant with the drugs, therapeutic goal cant be achieved. 
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