pharma 1.5 rdu_marbella

Pharmacology 1.5 July 4, 2012

Rational Drug Therapy Dr. Angeles Marbella

Group 5 | Joie and the Angs of 4

OUTLINE

I. Introduction II. List of Possible Treatments III. Process of Rational Prescribing IV. Cases with Complete Rational Drug Prescribing V. Conclusion

Objectives: • To review the process of rational drug therapy

Information in Times New Roman are taken from the Pharmacology Laboratory Workbook

I. INTRODUCTION Drug • WHO: any substance used to modify or explore physiological

systems or pathological states for the benefit of the recipient

Rational Drug Therapy • The most common decision of a doctor is to give treatment through prescribed drugs

• But not all health problems need treatment with drugs • Rational drug use: based on SANE criteria (safety, affordability,

need & efficacy); described by some pharmacologists as the RULE OF RIGHT: the right drug given to the right Pt.

P-‐Drug and P-‐Treatment • Not all diseases need to be treated by a drug • Not all P-‐treatment includes a P-‐drug Patient #1 Manny, 54 y/o, complains of a severe sore throat. No general symptoms, slight redness in the throat, no other findings. Patient #2 Mario, 43 y/o, complains of a sore throat. Slight redness of the throat, no fever and no other findings. Past history revealed that he is taking Loperamide for his chronic diarrhea. • Loperamide: side effects include decrease peristalsis of

intestine; dryness of mouth • A very important component of your patient’s history is to know

what drugs/medication your patient has been taking. Patient #3 Corazon, 32 y/o, very sore throat, caused by severe bacterial infection, despite penicillin prescribed last week. • Problem: patient stopped taking medicine • Its important to finish the course of treatment (specially

antibiotics) to prevent reoccurrence or resistance of the causative agents.

Patient #4 Magdalena, 23, complains of a sore throat but is also very tired and has enlarged lymph nodes in her neck. She has slight fever and has come for the results of last week’s laboratory exam. • Ask for important incidence/s in the past • Sore throat is secondary to an underlying systemic illness

Patient #5 Leny, 19, student, complains of sore throat. Slight redness of the throat, but no fever and other findings. She is a little shy and has never consulted you before for such a minor complaint. • Sometimes patients come to you for advice that are not related

to their chief complaint. • Further hx: patient would just like to seek an advice for delayed

menstruation that may have been caused by pregnancy Patient #6 Morris, 44, has sleeplessness for the past 6mo and comes for a refill of Diazepam tablets 5mg taken before sleeping. He wants 60 tablets. • Patient is drug-‐dependent. As doctors, you must recognize

which patients really need the drugs and those who just want to get high.

II. LIST OF POSSIBLE TREATMENTS

• Advice and information (to educate your patient) • Non-‐drug treatment (e.g. drink oregano) • Drug treatment: P-‐Drug For General Guidelines for drug use, please refer to page 3 of the Pharmacology laboratory workbook • Referral (if the problem is beyond your scope of expertise)

III. PROCESS OF RATIONAL PRESCRIBING

1. Define the patient’s problem 2. Specify the therapeutic objective 3. Verify whether your P-‐treatment is suitable for this patient 4. Start the treatment 5. Give information, instructions and warnings 6. Monitor (and/or stop) treatment (ask yourself is it effective or not?)

Note from trans group: These steps are almost the same as steps in the Process of Rational Prescribing as stated in the Pharmacology laboratory workbook. Kindly refer to page 3 of the workbook as supplementary reference.

Steps for Selecting a P-‐drug 1. Identify a patient’s problem. 2. Specify the therapeutic objective. 3. Select a drug on the basis of comparative efficacy, safety, suitability and cost (ESSC).

4. Write a correct prescription. 5. Counsel the patient on appropriate use of the medicine. 6. Make appropriate arrangements for follow-‐up. Note from trans group: If you look at it, these are the same steps as the Process of Rational Prescribing. We didn’t merge them since they were stated separately in the lecture and there’s no mention that they’re the same.

1. Define the Patient’s Problem • Diagnosis • Pathophysiology o Must be known to be able to prescribe a correct drug

2. Specify the therapeutic objectives • Possible goal/objectives:


a. Cure-‐ treat the cause. Ex. antibiotics b. Relief-‐ remove the symptom. Ex pain meds c. Prevention. Ex. vaccination d. Modifying physiologic process or underlying pathology. Ex use of contraceptives

• Other examples: o To decrease the diastolic BP o To cure an infectious disease o To suppress feelings of anxiety

Patient #7 5y/o, male child was brought to the clinic because of an open wound measuring about 2cm x 3cm, no pus noted, with minimal tenderness at the left superior portion of his back • Diagnosis: non-‐infected wound • Objective: to prevent infection. • Treatment: Teach the patient’s mom how to clean the wound

Patient #8 1y/o boy was brought to your clinic because of watery based stools, non bloody, non-‐mucoid occurring for 7x. PE: active, not irritable, eyeballs not sunken, dry lips, moist oral mucosa, other systems unremarkable • Diagnosis: diarrhea-‐non-‐infectious, probably viral; could be

acute gastroenteritis; no signs of dehydration • Objective: prevent dehydration. So you replace fluids lost by

giving ORS etc.

Patient #9 21 y/o male consulted because of failure to pass stools for at least a week. No other associated symptoms. PE is unremarkable • Diagnosis: constipation, probably functional constipation • Objective: Restore normal bowel movement of patient through

the use of laxative or dietary change 3. Verify the suitability of your P-‐treatment • Check effectiveness and safety (advice, information, non-‐drug measures, P-‐drug, referral)

• P-‐drug o Is a drug that is ready for action: a drug treatment of first choice with its strength, dosage form, duration of treatment and necessary warnings and information to the patient

Why develop your own set of P-‐drugs? • You have the responsibility for your patient’s well being (you

are responsible for everything you do to your patient and what ever happens to him, you have to know what you’re doing)

• You will learn how to handle pharmacological concepts and data (so, don’t get influenced by med reps, analyze yourself it the drug is good for your patient)

• You will know the alternatives when your P-‐drug choice cannot be used

• You can evaluate new information on new drugs and be able to update list

4. Select a drug on the basis of comparative efficacy, safety, suitability and cost (ESSC) Efficacy • Shows data on pharmacodynamics and pharmacokinetics (absorption, distribution, metabolism, excretion)

• Ability of drug to accomplish what it is intended to do • Each drug must meet adequate standards of quality Safety • Summarizes possible side effects and toxic effect • Research incidence of frequent side effects and safety margins should be listed

• Remember almost all side effects are directly linked to the working mechanism of the drug, with the exception of allergic reactions

Suitability • Applied to individual patients (high risk: pediatric, geriatric, pregnant, lactating mother)

• Contraindications are related to the patient’s condition (e.g. liver or renal failure)

• Interactions with food or other drugs can also diminish or strengthen the effect of the drug (again: always ask if your patient is taking other drugs before prescribing)

• Convenient dosage form or dosage schedule have a strong impact on patient adherence to the treatment o The less frequent it must given (ex. Once daily), the more convenient it is for the patient; thus, better compliance

Cost • Use Total cost of treatment rather than the cost per unit • Give higher points if the drug is cheaper • Factor-‐in the duration of the treatment (ex. Single dose vs. maintenance meds) when you consider the cost.

Table 1. Inventory of Effective Drug Groups (Same table used for specific drugs)

Efficacy Safety Suitability Cost

Drug group1

Drug group2

Drug group3

• Scoring: o Assign percentages to the different criteria, e.g. 60%

efficacy, 20% safety, 10% suitability, 10% cost (Sometimes, cost is not included)

o Use + or -‐ : can range from – to 4+ (not a definite range)

IV. CASES WITH COMPLETE RATIONAL PRESCRIBING

Patient #10

A 60 y/o male, with no previous medical history. During the last month, he has several attacks of suffocating chest pain, which began during physical labour and disappeared quickly after he stopped. He has not smoked for 4 years. His father and brother died of a heart attack. Apart form occasionally taking aspirin he has not used any medication in the past year. PE reveals BP 130/85, regular pulse at 78/min, body weight normal and a murmur over the right carotid artery. 1. Define the problem: Angina pectoris, stable 2. Specify Therapeutic Objectives: • Stop an attack as soon as it starts: By decreasing preload, contractility and afterload


3. Make an inventory of effective drugs: • Nitrates • Beta blockers • Ca channel blockers

4. Choose an Effective group according to ESSC criteria Table 2. Selecting an Effective Group According to ESSC Criteria (sometimes cost is not included)

5. Choose the P-‐drug using the ESSC criteria Table 3. Choosing specific P-‐drug using ESSC Criteria

6. Write the Prescription

7. Counsel the patient on the appropriate use of the drug; Minimum info: 1. Effects of the drugs: when, how long 2. Side effects 3. Instructions 4. Warnings: e.g. do not take more than 5 tablets for it may cause hypotension

5. Future consultations: appointment for follow-‐up 6. Clarify (Is everything clear?)

Patient #11

52 y/o taxi driver complains of a sore throat and cough which started 2 weeks earlier with a cold. He has stopped sneezing but still has a cough, especially at night. The Pt. is a heavy smoker who has often been advised to stop. Further history and examination reveal nothing special apart from throat inflammation. 1. Diagnosis: Post-‐inflammatory cough 2. Therapeutic Objective: Suppress the cough 3. List possible P-‐drug groups:

• Opioid agonist • Anti-‐histamine

4. Drug Group ESSC

Table 4. Choosing an Effective Group Accdg to ESSC criteria

5. Drug ESSC Table 5. Choosing an Effective P-‐DRUG Accdg to ESSC criteria

6. Write the Prescription

Patient #12 A 1y/o boy was brought by the mother because of 7x loose watery stools. Stools are watery, non bloody, non-‐mucoid, non-‐foul smelling amounting to ½ cup per episode. There is no accompanying fever, vomiting or abdominal pain. On examination, the child is active with dry lips, thirsty, eyeballs slightly sunken, clear breath sounds, good cardiac tones, soft and non-‐tender abdomen, pulses full.


1. Diagnosis: acute gastroenteritis, mild dehydration, probably viral

2. Therapeutic Objective: • Rehydrate Pt. • Prevent further dehydration

3. List of possible drugs: • ORS • Opioids • Zinc

4. Drug Group Table 6. Choosing an Effective Group Accdg to ESSC criteria

5. Drug ESSC Table 7. Choosing an Effective P-‐Drug Accdg to ESSC criteria

6. Prescription

V. CONCLUSION A well-‐chosen P-‐DRUG will always depend on the proper assessment of the problem of the Pt. and the knowledge of the pharmacological properties of the different drugs.

-‐FIN-‐

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