an important ppt for medical students and prescribing clinicians of medicine..... which deals with the methodology of right prescribing...... enjoy reading.... <3.... satya

5. GIVE RELAXED ATTENTION

6. ONE OF THE FIRST DUTIES OF THE
PHYSICIAN IS TO EDUCATE THE
MASSES NOT TO TAKE
MEDICINE….!

7. PRINCIPLES OF
PRESCRIBING
Dr. V.SATHYANARAYANAN M.D
PROFESSOR OF PHARMACOLOGY
SRM MCH & RC

9. PRINCIPLES OF PRESCRIBING
 AT ANY TIME 40-50% OF ADULTS TAKE
PRESCRIBED MEDICINE.
 PRESCRIPTION IS THE FINAL DECIDING
THING FOR THE ILLNESS PATIENT
 INCREASE IN NUMBER OF NEW DRUGS.
 COMPLEX DISEASE PATTERN.
 POLYPHARMACY.

14. IMPACT OF IRRATIONAL
PRESCRIBING
 Delay in cure
 More adverse effects
 Prolonged hospitalisation
 Emergence of antimicrobial resistance
 Loss of patient’s confidence in the doctor
 Loss to the patient/community
 Lowering of health standards

23. WHAT DOES IT REQUIRE?

24. FOLLOW GOOD
PRESCRIBING

25. WHAT IS GOOD
PRESCRIBING?

26. WHAT IS GOOD
PRESCRIBING?
 Appropriate drug
 in the correct dosage of an Appropriate
formulation
 At the correct frequency of administration
 For the correct length of time.

31. GOOD PRESCRIBING
 It includes not prescribing any drug at
all.

33. GOOD PRESCRIBING
REQUIRES:
 DETAILED KNOWLEDGE OF THE
PATHOPHYSIOLOGY OF THE DISEASE
 CLINICAL PHARMACOLOGY OF THE
DRUGS

36. PRESCRIBING IS NOT SIMPLY
MATCHING THE DISEASE AND
THE DRUG….…!

37. INDIVIDUALISE THE
THERAPY

38. TWO HELPFUL CONCEPTS
 BENEFIT: RISK RATIO
 EVIDENCE BASED MEDICINE

39. BENEFIT:RISK RATIO
IN PRESCRIBING

41. THE BENEFIT:RISK RATIO IN
PRESCRIBING
 Benefits to the patient is accompanied by
the risk of Adverse effects
 Always try to assess the likely Benefit : risk
ratio before instituting therapy.

42. ASSESSING RISK:BENEFIT
RATIO
 Consider five factors:
1) The seriousness of the Problem to be treated
1) The efficacy of the drug you intend to use.
2) The seriousness & frequency of possible ADR
3) The safety of other drugs that might be used
instead
4) The efficacy of other drugs that might be used
instead

44. SOME EXAMPLES
 Choice of an antibiotic in UTI in a 2
month pregnant woman.

45. Elderly lady with giant cell arteritis treated with
prednislone

46. Treating male elderly patient with Angina
pectoris for impotence

47. EVIDENCE-BASED
MEDICINE
 Search and evaluate the literature for
 efficacy,
 safety
 Appropriateness of the particular
therapeutic measure

49. Clinical decisions should be based on the
best scientific evidence available at the time.

50. EVIDENCE-BASED
MEDICINE
This can be obtained from:
 Standard text books
 Review articles from leading journals
 Other doctors (lectures, CME etc.)
 Systematic review of clinical trials (published
and unpublished)
 Websites and Database

58. EVIDENCE-BASED MEDICINE
Therapeutic decisions should be
rationally guided by
 Rigorous analysis of the best available
evidence.
 Unbiased analysis.

62. HOW TO CHOOSE A DRUG
?

64. HOW TO CHOOSE A
DRUG ?
 Ask the following sequence of questions before
writing the prescription
 Indicated?!!
 Which drug?
 Which class---which group----which particular drug
 Which route?
 Which formulation?
 What dosage regimen?
 With experience, the process becomes automatic

66. HOW TO CHOOSE A
DRUG ?
ASK THE FOLLOWING QUESTIONS BEFORE
WRITING THE PRESCRIPTION
1)Is drug therapy indicated ?
 A) Is the intending treatment necessary?
 B) Is the benefit greater than the risk?
Ex)
 Vitamins & minerals as tonics in the absence of
any evidence of deficiency
 antibiotics in acute diarrheas
 cerebral vasodilators in senile dementia

68. WHICH DRUG ?
 If drug therapy is indicated,
 select the therapeutic class
 Select the group within the class
 Select the particular drug in the group
Ex) infection antibiotic (therapeutic class) 
penicillins (therapeutic group) amoxicillin
(particular drug).
CHF, hypertension  selection complicated

70. HOW TO MAKE A RATIONAL
CHOICE OF THE DRUG ?

71. HOW TO MAKE A RATIONAL
CHOICE?
 Choose the drugs which you are most familiar.
Consider following factors:
 Pharmacokinetic (Absorption, distribution,
metabolism, excretion)
 Pharmacodynamic ( potency-sulfonylureas in
DM )
 Therapeutic considerations.( disease features,
severity, co-existing diseases, avoidance of ADR,
Adverse drug Interactions)
 Patient compliance

74. WHICH ROUTE OF
ADMINISTRATION?

75. WHICH ROUTE OF
ADMINISTRATION?
 DICTATED BY THE DRUG CHOSEN. (Ex.
Dopamine)
 Sometimes particular route is preferred for
particular benefit. (Ex. Nitrates in angina
pectoris)
 Rectal route diazepam in children
 I.M depot inj. In schizophrenia to ensure
compliance.
 S.C insulin for prolonged effect.
 I.V Furosemide in CHF

76. WHICH FORMULATION ?

77. WHICH FORMULATION ?
 Oral  tab, cap, granules, suspension, syrup
 Injection powders for reconstitution, solution
ready for inj. (Single, multiple dose)
Choice depends on:
 Ability to produce adequate plasma concentration
 Patient compliance (sustained release)
 Side effects (enteric coated aspirin)
 Age- children –pleasant tasting suspension, old-
tasteless solution

79. WHAT DOSAGE REGIMEN?

80. WHAT DOSAGE REGIMEN?
 IT HAS THREE ASPECTS:
1) The dose of the drug.
2) The frequency of it’s administration.
3) The timing

81. PRINCIPLES THAT GOVERN
DOSAGE REGIMEN: BE FLEXIBLE
 Pharmacokinetic variability-(absorption,
metabolism, elimination) increase Or
decrease Dose
 Pharmacodynamic variability- DRC varies
between individuals, no response in initial
dose increase the dose without ADR
 Patient factors- age, body wt, hepatic and
renal function.
 Disease factors- degree of the disease (ex-
NSAIDS in inflammation)

82. TAILORING THE DOSAGE
REGIMEN : BE SYSTEMATIC
 Look up in a reliable source.
 Consider dose related toxicity of the drug (ex- more
for lithium , gentamicin, digoxin, phenytoin)
 Decide on the initial dosage.( generally start at the
lower end, increase it gradually), be flexible
 Consider pharmacokinetic factors that alter dosage (
renal insufficiency)
 Consider DRC (ex- insulin required more in diabetic
ketoacidosis)
 Consider drug interactions
 Other factors like Age, weight

83. HOW FREQUENTLY?

84. HOW FREQUENTLY TO
ADMINISTER?
 Usually fixed of a given drug in a given
formulation
 Sometimes need to be altered according to
the frequency of symptoms (ex- GTN in
angina)
 To prevent ADR ex-corticosteroids on
alternate days
 To improve compliance –(MR preparations)

85. TIMING

86. TIMING OF DRUG
ADMINISTRATION
 In most cases - Fixed.
 To minimize the ADR- last thing at night
 Timing may be important in some cases ( ex-
diuretics, sedatives, corticosteroids)
 Timing of symptoms ( ex- antacids, NSAIDS,
GTN)
 Timing in relation to the meals (ex-most
penicillins, tetracyclines, azithromycin best before
food, NSAIDs like aspirin with food)

89. FOR HOW LONG ?

90. FOR HOW LONG ?
 It depends on nature of the disease,
symptoms & collective experience.
 The scale varies from single dose of
aspirin for headache to life long treatment
for diabetes, hypertension.
 Difficulty & controversy arise in treatment
of intermediate duration

94. FOR HOW LONG SHOULD
TREATMENT LAST?
 Antibiotics duration varies from infection
to infection
 It depends on infecting organism, site of
infection, response to treatment( ex-
penicillin for tonsillitis- 7-10 days, NGU - 10-
21 days, tuberculosis 6-12 months)
 Warfarin in DFT- duration uncertain

95. GOOD PRESCRIBING IS TO
GIVE:
 RIGHT DRUG IN THE RIGHT DOSAGE
 RIGHT FORMULATION
 AT THE RIGHT FREQUENCY
 FOR THE RIGHT DURATION

97. PROCESS OF RATIONAL
PRESCRIBING
 Establish a diagnosis
 Define therapeutic problem and goal
 Select the right drug by good
prescribing
 Provide proper information
 Monitor compliance
 Monitor goal
 Modify if needed
 Monitor ADR if occur & modify

100. INSTRUCTIONS TO THE
PATIENT
 Effects of the drug
 Side effects
 Why, How and when instructions
 Precautions/ warnings

102. The good physician treats the disease;
The great physician treats the patient
who has the disease !
WILLIAM OSLER