RATIONAL DRUG SELECTION Flashcards
(22 cards)
rational drug selection
The World Health Organization (WHO) definition of rational drug selection is that “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”
irrational use
50%
examples of irrational medication use outlined by the WHO include polypharmacy, inappropriate prescribing of antimicrobials, overuse of injections versus oral preparations, and failure to follow guidelines when prescribing.
who model
he WHO model for rational drug prescribing has been used for more than 20 years and provides a systematic approach to prescribing (de Vries, Henning, Hogerzeil, & Fresle, 1994; WHO, 2017). The first step in the WHO process is accurate diagnosis and determination of the therapeutic objective—for example, treating an infection. The appropriate treatment is chosen with these factors in mind. It is critical that the provider collaborates with and educates the patient regarding the therapy. The chosen therapy then needs to be monitored to determine the effectiveness of the regimen (Box 3-1).
THE WORLD HEALTH ORGANIZATION’S SIX-STEP MODEL OF RATIONAL
PRESCRIBING
step 1: Define the patient’s problem.
step 2. Specify the therapeutic objective.
step 3: choose the treatment.
Step 4 : Start the treatment.
Step 5 : Educate the patient. Step 6: Monitor effectiveness.
Define the Patient’s Problem
assessment of the patient and formulation of a working diagnosis and possible differential diagnosis.
Early screening of high-risk patients maximizes the benefits of pharmacological treatment (WHO, 2012).
Once the diagnosis is made, the provider develops a plan of care. Is there a clear indication for drug therapy?
What drugs are effective in treating this disorder?
Specify the Therapeutic Objective
Before deciding what medication to prescribe, it is important to clarify the therapeutic objective or goals of therapy
provider clarify whether the treatment goals are curative, symptom relieving, or preventive. The WHO model recommends that the provider include the patient in this stage of the process so the patient is a partner in the treatment regimen
costs
lifestyle
Choose the Treatment
two-step process:
first determine what the appropriate therapy would be using evidence-based guidelines;
second, individualize the drug choice for the specific patient
consider :
pharmacokinetics and pharmacodynamics
ge and gender of the patient, pharmacogenetics, consideration of other drugs that the patient may be taking, and potential interactions
Individualizing drug therapy requires examining the suitability of the drug for the patient. The WHO model recommends that the provider examine the drug and the dose, the dosage schedule, duration of treatment, effectiveness, and safety
THE ‘I Can PresCribE A Drug’ MNEMONIC
Indication
Contraindications
Precautions
Cost/Compliance Efficacy
Adverse effects Dose/Duration/Direction
Start the Treatment
drug, dose, and schedule are accurate. At the time of writing the prescription, drug costs need to be addressed with the patient.
Educate the Patient
Up to 50% of patients do not take their medications as prescribed or do not take them at all
Patient education regarding the purpose of the medication, how the medication works, instructions for administration, what benefits to expect from the medication, and potential adverse drug effects will improve adherence to the medication regimen
Monitor Effectiveness
two types of monitoring:
passive and active
passive =patient
Active monitoring occurs when the provider schedules a follow-up examination to determine the effectiveness of the drug therapy
DRUG FACTORS INFLUENCING DRUG
SELECTION
Pharmacodynamic Factors
Pharmacokinetic Factors
Therapeutic Factors
Safety
Cost
Patient Factors
Provider Factors
selections; Pharmacodynamic Factors
specific and selective to target the tissues affected by the disease to have the greatest therapeutic effect with the
least severe adverse effects
therapeutic index
The relationship between a drug’s desired therapeutic effects and its adverse effects is called its therapeutic index (see Chapter 2). Drugs with a low or narrow therapeutic index may require close monitoring for toxicity or adverse effects, whereas drugs with a wide therapeutic index are fairly safe and require less monitoring.
selection: Pharmacokinetic Factors
When deciding which drug in a class to prescribe, the pharmacokinetic properties of a drug may influence drug selection.
For example, drugs within a drug class may differ in their ability to cross the blood–brain barrier, either being more effective (i.e., antiseizure medications) or causing more adverse central nervous system effects (i.e., first generation antihistamines).
Another consideration is metabolism. Different drugs in a class may use different cytochrome P450 (CYP450) enzymes, which may influence metabolism or drug interactions.
Drugs that are excreted almost exclusively by the kidneys may not be appropriate for a patient with decreased renal function, such as an older adult. Therefore, a patient’s renal function and the pharmacokinetics of the drug need to be evaluated during the drug selection process. Additionally, the dose–response curve and half-life will determine the dosing schedule, with fewer doses per day encouraging adherence to the drug regimen
selection: Therapeutic Factors
reviewed in the literature and observed in the individual patient.
The effect of a drug on decreasing morbidity, mortality, and hospitalization is examined, as well as the drug’s ability to relieve symptoms and treat the disease process
RCT/EBC- be careful as usually healthy patients
NNT/NNH
Using the “numbers
needed to treat” (NNT) or “numbers needed to harm” (NNH), which compare the absolute risk of the medication versus the effectiveness, may be more useful than RCT results
selection: safety
varies with pop/individ
disease process
age , preg
allergies
selection: COST
cost to the patient and the cost to the health-care system or society at large
selection: Patient Factors
drug adverse effects that influence adherence,
health beliefs,
values,
current drug therapy that may interfere with the new drug
age
conditions - mental health
Previous Adverse Drug Reactions;renal dysfunction, are at higher risk of experiencing ADRs.
medication that has the fewest ADRs will promote adherence.
Health Beliefs
Current Drug Therapy-drug interactions
Patient Age
Pregnancy
selection :Provider Factors
Ease of Prescribing or Monitoring
Formularies
