Rational Drug Use in Special Patients by Dr. Busari

1. RATIONAL DRUG USE/DRUG USE IN SPECIAL PATIENTS DR BUSARI. A.A (MB.BS, M.Sc., MMCP, FWACP) Dept. Of Pharmacology, Therapeutics and Toxicology

2. What is Rational Use of Drugs? RUD is defined as the prescription of medications appropriate to patient’s clinical needs, in doses that meet their own individual requirements, for an adequate period of time, and at the lowest cost to them and the community. (WHO ) The conference of experts on the rational use of drugs, convened by the WHO in Nairobi in 1985

3. Magnitude of Irrational Use of Medicine (IUM) • Magnitude of irrational use of medicines (IUM) is enormous. • According to the WHO more than half of medicines prescribed, dispensed or sold globally are done inappropriately (WHO. 2014). • Routledge et al., (2004);documented examples of irrational use of medicines to include polypharmacy, and oversuse.

4. Magnitude of IUM • Failure to prescribe following established clinical procedures such as, national treatment guidelines and hospital policies; (Younis et al., 2009) • (Norris et al., 2011) in inadequate dosage and sometimes use of antibiotics for non-bacterial infections are part of IUM • Higher rates of antibiotic use have been reported in several developing countries, including Pakistan, Nepal, Eritrea, Lebanon, Yemen, and Nigeria.

5. Components of rational drug prescribing • Appropriate indication • Appropriate drug in terms of safety, tolerability , efficacy and suitability to the patient • Appropriate dose, duration and route of administration to specific patient features. • No existing contraindications for the patient and adverse drug reactions are minimal. • Correct dispensing with appropriate information given to the patient • Appropriate monitoring of the outcome of the medication to the patient; its effectiveness and untoward effects

6. Factors influencing rational Drug prescribing • Knowledge of the prescriber • Role models: One tends to follow prescription plans of one’s teachers or role models • Desire for prompt symptomatic relief at all cost • Imprecise diagnosis: medications given to cover all possible causes of the illness • Drug promotion and exaggerated claims by manufacturers • Unethical inducements: Gifts, dinner parties, conference delegations • Patient demands: predilection for a particular brand, misconceptions, unrealistic expectations, "pill for every ill" belief.

7. Irrationalities in prescribing • Use of drug when none is needed e.g. antibiotic for viral fevers • Use of drug not related to the diagnosis e.g. antiulcers for any abdominal pain • Selection of wrong drug e.g. β-blockers for an asthmatic hypertensive patient • Incorrect route of administration e.g. injection when drug should be given orally • Incorrect duration of administration e.g. prolonged post-surgical use of antibiotics

8. Irrationalities in prescribing 6. Unecessary use of drug combinations. E.g. ibrupofen and paracetamol as analgesic • Unnecessary use of expensive medicines when cheaper ones available are equally effective (craze for new medicines). • Unsafe use of drugs e.g. anabolic steroids for children

9. Consequences of irrational drug prescription • Ineffective & unsafe treatment • over-treatment of mild illness • inadequate treatment of serious illness • Exacerbation or prolongation of illness • Distress & harm to patient • Increase the cost of treatment • Increased drug resistance - misuse of anti-infective drugs • Increased Adverse Drug Events • Increased morbidity and mortality • Loss of patient’s confidence in doctor (or doctors in general)

10. Steps of rational drug use • Step:- I • Identify the patient’s problem based on symptoms & recognize the need for action • Step:- II • Diagnosis of the disease – define the diagnosis • Step:- III • List possible intervention or treatment (drug or no drug) – Identify the drug • Step:- IV • Start the treatment by writing an accurate & complete prescription e.g. name of drugs with dosage forms, dosage schedule & total duration of the treatment

11. Steps of rational drug use • Step:-V • Given proper information instruction & warning regarding the treatment given e.g. side effects (ADR), dosage schedule & dangers/risk of stopping the therapy suddenly • Step:-VI • Monitor the treatment to check, if the particular treatment has solved the patient’s problem. • Passive monitoring – done by the patient himself. Explain him what to do if the treatment is not effective or if too many side effect occurs • Active monitoring - done by physician and he make an appointment to check the response of the treatment

12. Instruction to the patients Patient instructions Warning (Disulfiram Reaction): • Effects of the Drug • Adverse effects • Instructions • Precautions to be taken • Symptoms: • flushing of the skin • accelerated heart rate • shortness of breathe • nausea, vomiting, throbbing headache • visual disturbance • mental confusion, postural fainting and circulatory collapse

13. USE OF DRUGS IN SPECIAL PATIENTS

14. USE OF DRUGS IN SPECIAL PATIENTS

15. Cockcroft- Gault formula • If only the adult dose is known for drug that requires renal clearance , correction can be made using this formula • Creatinine clearance= (140-age)× Weight(kg) 72 × Serum creatinine (mg/dl)

16. USE OF DRUGS IN SPECIAL PATIENTS

17. USE OF DRUGS IN SPECIAL PATIENTS

18. Paediatric Drug Dosage • Dose calculation on the basis of age, surface area and weight Based on age (young’s rule) • Dose = Adult dose x Age ( years) Age +12 Based on weight • Dose = Adult dose x weight(kg) 150

19. USE OF DRUGS IN SPECIAL PATIENTS

20. Teratogenic effect • Teratogen : any drug or substance is labelled teratogen if: • It produces characteristic sites of malformation with selectivity for certain organs • Exerts its effect at a particular stage of fetal development • Shows a dose dependent incidence Teratogenic mechanism: poorly understood • Indirect action: vasoconstriction leads to reduced uterine blood supply and thus fetal anoxia. Eg: prostagladin analogues, ergot alkaloids • Direct action on process of differentiation eg: vitamin A analogues produce significant teratogenic effect by altering the normal process of differentiation. • Deficiency of a critical substance may cause abnormality eg: spina bifida due to folic acid deficiency

21. Teratogenic effect • Continuous exposure to a teratogen may produce cumulative effect or may affect multiple organs which are undergoing development eg: chronic alcohol consumption leads to undergoing development, facial abnormalities • Direct action: eg : thalidomide when administerd during 4-8 weeks causes phacomelia as arms and legs are developed in this period

22. Teratogenic effect

23. Drugs with significant teratogenic effects

24. FDA category/rating of drugs in pregnancy

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26. USE OF DRUGS IN SPECIAL PATIENTS

27. Formula for dose calculation in renal insufficiency CORRECTED DOSE = NORMAL DOSE X PATIENT’S CREATININE (CL) NORMAL CREATININE (CL)

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