Friday, February 19, 2010

Rational Drug Use

Drugs are an essential component of health care delivery. When used rationally, they produce the desired effect of improving patients ailments. Their irrational use on the hand leads to prolongation of the illness, development of adverse effects, and unnecessary expense. The use of medicines inappropriately and inefficiently is a very serious problem all over the world and at any given time, it is estimated that more than 50 % are either incorrect prescriptions or inappropriately dispensed or sold. Many patients do not know how to correctly take the prescribed drugs or do not have access to essential medicines. Irrational drug use pertains to the use of drugs when they are not needed. It also means prescribing drugs with out adequate scrutiny regarding their efficacy, safety, affordability, and suitability to the patient.
Rational drug use (RDU) is often defined as

"the use of an appropriate, efficacious, safe and cost-effective drug for the correct indication in the right dose and formulation at correct intervals and duration."

This involves adoption of the essential drug concept & development and usage of evidence based clinical guidelines. Other vital strategies to promote RDU include unbiased and independent drug information and continuing medical education.

Types of Irrational use of Medicines:

There are several types of irrational use of medicines -
  1. Use of medicine when no drug therapy is needed (antibiotics in viral upper respiratory tract infections)
  2. Use of wrong medication for conditions requiring specific drug therapy (Fixed drug combination of Norfloxacin and Metronidazole in diarrhea)
  3. Use of medicine of doubtful or unproven efficacy (Vitamins in the absence of deficiency)
  4. Use of medicine of uncertain safety (ayurvedic bhasmas)
  5. Failure to prescribe available, safe and effective agents (Under use of antidepressants or antihypertensives)
  6. Incorrect administration, dosages or duration.
  7. Use of too many drugs per patient (Polypharmacy)
  8. Use of injections when oral formulations available
  9. Inappropriate self-medication, often of prescription only medicine
  10. Incorrect treatment of disorders
  11. Poor compliance

Reasons for Irrational drug use:

  1. Misinformation, misleading beliefs or inability to communicate symptoms correctly on part of the patient.
    • Wants quick response - believes injections work faster
    • Unhappy if no medicine prescribed
    • compliance is big problem - once symptoms subside, stops treatment
      • Adherence of patients to a treatment program is necessary for the success of the program. Non-adherence or non compliance results from factors related to the drug, the patient, the prescriber and the environment.
    • Almost all drugs available OTC
  2. Lack of accurate and correct information of newer agents, workload and pressure to prescribe on part of the prescribers
    • Poor diagnostic support - empirical treatment
    • No evidence based guidelines readily available
    • Continuing education programmes
  3. Poor medical facilities and supply of drugs
    • Vaccines and many other drugs not stored at required temparature
    • Over 80,000 formulations in the country, many doubtful value
  4. Inadequate drug regulation -
    • Process for marketing approval of new drugs
    • Controls on OTC drugs
    • More effective definition of prescriber
    • Quality assurance of products
    • good drug distribution systems
    • availability and price control of essential drugs
    • Unbiased drug information
    • Unethical promotion of drugs

Impact of Irrational Drug use:

  • Poor quality of health care delivery - Increased morbidity and mortality
  • Waste of scant resources on using wrong medicine
  • Irrational drug use leads to ineffective and unsafe treatment, worsening or prolonging of illness and adverse drug reactions.
  • It also unnecessarily adds to the economic burden of the patients, the government or the insurance system.
  • The widespread antibiotic resistance is also partly a result of irrational use of antibiotics.

Guidelines for Rational Drug Use:

  1. Define the patient's problem - define the therapeutic objective
  1. Use drug only when indicated and when potential benefits outweigh any risks
  1. seriousness of the problem to be treated
  2. efficacy of the drug to be used
  3. severity and incidence of possible ADRs
  4. safety and efficacy of alternative drugs if any
    • e.g., phenylbutazone, commonly used in the treatment of osteoarthritis in the past, because of its high benefit-to-risk ratio, is currently replaced with safer drugs.
  5. Assessment of benefit-to-risk ratio may not always be easy. The following examples show this problem:
    • The benefit of adding digoxin to a diuretic and vasodilator vis- à-vis the risk of its toxicity in the treatment of congestive cardiac failure. This might depend on the cause of the heart failure, patient compliance, renal function and ease of monitoring of plasma digoxin concentration
    • The benefit from a course of antibiotic in treating urinary tract infection in two months pregnant as compared to the risk of treatment to the fetus. Here the risk of teratogenesis needs to be compared to the risk of renal damage to the mother as a result of untreated infection
  1. Choose a drug of proven efficacy and safety, which is suitable and affordable for the patient
    • The use of International Non Proprietary Names (INN) or generic names of drugs in prescribing is an essential component of good prescribing practice. This is because generic drugs are less costly, an important factor in our country, and for a generic prescription any suitable product can be dispensed hence avoiding delay while looking for a specific brand.
    • Avoid same class drug
  1. Choose suitable dose
  1. Route of administration: e.g.,
    • Crystalline penicillin is given by intravenous route for severe infections; Intramuscular benzathine penicillin monthly or oral penicillin daily can be given for rheumatic fever prophylaxis.
    • Beta agonists like salbutamol are given through nebulizers or inhalers in acute asthmatic attack for fast action.
  2. Formulations : e.g.,
  • oral formulations include tablets, capsules, granules, elixirs, suspension; injection formulations include lyophilized powders, solution.
    • For acute pain, prescribe soluble buffered aspirin because of fast action
    • For chronic rheumatic disease, prescribe enteric-coated formulation
  1. Dosage regime(dose) frequency/timing of administration: the following need to be considered
    • Kinetic variability: for poor absorption prescribe larger dose or prescribe another drug/route
    • Dynamic variability: for less effect, prescribe larger dose
    • Characteristics of the patient: tailor the dose according to body weight and other factors while prescribing
    • Characteristic of the disease: e.g., dose of codeine used to suppress cough is lower than that required to relieve pain
    • Choosing a dosage regimen by
      • referring to a reliable source of information
      • considering dose related toxicity
      • deciding the initial dose: when there is no guide, start with low dose and increase gradually (ACE inhibitors, levodopa); for some drugs to increase the dose may be necessary because of tolerance (opiates); sometimes starting with a loading dose before giving a maintenance dose is required (digoxin); in some cases to start with high dose and reduce gradually might be required (corticosteroids)
      • Considering kinetic factors which may alter dosage requirements: e.g., impaired renal function
      • Considering dose response relationship for the patients: e.g., higher dose of insulin for ketoacidosis, and lower dose of antipsychotic drugs in treatment naive patients
      • Considering other patient characteristics like age, sex weight, etc
    • Frequency of drug administration:
      • usually fixed for a given formulation;
      • sometimes may be altered (e.g., splitting the dose of spiranolactone - in two to avoid GI irritation),
      • frequency of nitroglycerin administration depends on the frequency of symptoms
      • Timing of drug administration: The following are examples where timing is very important
        • To minimize ADR: tricyclic antidepressants to avoid dry mouth and drowsiness better to take it at bed time; potent diuretics better be given in the morning to avoid disturbance during the night
        • Timing of symptoms: e.g., anginal attack, use of antacids
        • Timing in relation to meals: penicillin to be administered before meal; aspirin to be administered with meal
      • Inform the patient - dose, duration, adverse effects if any
      • Monitor treatment
      • If drug ineffective find reason, any changes needed or monitoring required
      • Whether to continue drug or stop
    • Depends on the nature of the disease or symptom: e.g., A single dose of aspirin for headache;Insulin for chronic therapy; treatment with H2 blockers require six weeks as healing occurs with in this period, but longer periods of nightly administration may be required to prevent recurrence.
    • Duration of treatment of infection depends on: The infecting organisms , Site of infection, Response to treatment, Dosage of antibiotics
Educational strategies:

  • Informing and persuading prescriber - from students to practicing clinicians and community (teaching, seminars, face to face talks, distribution of printed matter, television etc)
The concept of P-treatment and P-drugs :

The first step in rational treatment is defining the patient’s problem, which is making a correct diagnosis. Once a diagnosis is made, one has to specify his/her therapeutic objective, what the physician wants to achieve with the treatment to be applied. Based on the therapeutic objective, one chooses a treatment of proven efficacy, safety, suitability and affordable cost from different alternatives.

The treatment may consist only of giving patients’ advice and information about their illness, non-drug therapy, treatment with drug, or a combination of these. For every diagnosis you make, the treatment plan you choose will be your P (personal)-treatment.

When for a certain diagnosis your P-treatment consists of drug treatment, you have got to choose a drug(s), on the basis of efficacy, safety, suitability, cost and availability. This will be your P - (personal) drug. P-drugs are list of drugs every subscriber got to choose for a particular problem based on the National Essential Drugs list and the Standard Treatment Guideline (STG). The prescriber, by choosing P-drugs which he prescribes regularly, becomes familiar with their effects and side effects. The P-drug concept is more than just the name of a pharmacological substance, it also includes the dosage form, dosage schedule and duration of treatment.


Leave a reply

Recent Blog Posts

Recent Comments