Introduction
Clinical pharmacology and therapy is the clinical specialty of using drugs well in real patients: individualised, effective, efficient and safe treatment based on evidence. It differs from pharmacology, which studies drugs mostly in preclinical (animal) settings.
Rational pharmacotherapy and the WHO P-drug concept
Rational pharmacotherapy means the right drug, in the right dose and regimen, at a reasonable cost, matched to the needs of the individual patient. It needs a correct diagnosis, knowledge of the patient (co-morbidities, other drugs, preferences), knowledge of the drug's pharmacokinetics and pharmacodynamics, and monitoring of efficacy and safety.
WHO's P-drug (personal drug) is the doctor's own drug of first choice for a common condition, with its formulation, dosing regimen and duration. It is chosen by four comparative criteria:
The P-drug steps
- Define the problem and the treatment objective.
- Choose a drug group, then a drug within it, by efficacy, safety, suitability and cost (each can be scored and weighted).
- Check the P-drug suits this patient; start treatment.
- Inform and warn the patient: why, how and how long to take it, missed doses, expected benefit, adverse reactions, interactions with alcohol and other drugs.
- Monitor efficacy and safety.
P-drugs differ between countries and doctors (availability, cost, guidelines). Because no treatment is risk-free, every prescription is a benefit–risk decision. Objective drug information comes from the SmPC (Summary of Product Characteristics).