1. ADVERSE DRUG REACTIONS
Dr. Rita Grace Y. Alvero

2. Adverse Drug Reactions
Introduction

3. Adverse Drug Reactions
Definition
any response to a drug that is noxious and unintended and that occurs at doses of an appropriately given drug used in man for prophylaxis, diagnosis or therapy

4. Adverse Drug Reactions
Significance
adverse - beneficial
significant - insignificant
apparent - hidden
severity
acute - chronic

5. Adverse Drug Reactions
Incidence
30% or > ADR
3% severe reaction
0.3% die
5% - OP basis
extremes of age
♀ > ♂
28% past Hx

6. Factors Affecting ADR Patient Related age sex genetic influences
concurrent diseases
compliance with dosing regimen
total number of medications
previous ADRs
misc. (diet, smoking, environment)

7. Factors Affecting ADR Drug Related doses, duration inherent toxicity
pharmacokinetics
pharmacodynamics

8. Types of ADR Type A (Augmented) Type B (Bizzare) Type C (Continuous)
Type D (Delayed)
Type E (Ending of Use)
Type F (Failure of treatment)

9. Type A
2 types – extension
side effect

10. Type B no formal response curve
very small doses can elicit the reaction
immunological

11. Type C
continuous, long term
dose and duration of therapy

12. Type D longer period of time
carcinogenesis, teratogenecity, immunotoxicity

13. Type E
withdrawal reactions

14. Type F substandard presence of toxic excipients
antimicrobial resistance
tolerance

15. Recognizing ADRs
Has this drug ever caused this type of reaction as reported in the lit?
Is the timing of the patient’s response to the drug typical of previous reports?
Can other likely reasons or causes for the patient’s syndrome be eliminated?
Has the patient ever had a similar response to this drug?
If the drug is discontinued, does the patient improve?
If the drug is restarted, does the syndrome recur?

16. Scoring 10 – 12 - likely ADR 7 – 9 - probable ADR 4 – 6 - possible ADR
0 – unlikely ADR

17. Management of AD

18. Points to Remember to Reduce Occurrence of ADR
Critically review the total cond of the patient
Use as few drugs as possible
Know well the drugs that you use
Do not change from 1 drug to another
Do not hesitate to use textbooks and other references
Be very careful when prescribing drugs known to exhibit a large variety of reactions / interactions

19. Points to Remember to Reduce Occurrence of ADR
Be aware of interactions
Regularly make an inventory of the drugs your patient is receiving
If your patient shows sign and symptom not clearly explained by the course of illness, think of ADR

20. 75 year old female
Dx: HPN (BP – 170/105)
Tx: Nifedipine 20 mg BID
Follow - up
1 mo later
(1st ff-up)
1 mo later
(2nd ff-up)
2 wks later
(3rd ff-up)
1 mo later
(4th ff-up)
BP 120/70
BP controlled
BP controlled
BP 180/100
Problems
dizziness
dyspepsia
swollen ankles
gout
swollen ankles
hypokalemia
Nifedipine
Furosemide
K supplements
Diclofenac 50 mg TID
+ Allopurinol Tx
Nifedipine 20 mg BID
Furosemide 2.5 mg OD
Ranitidine 150 mg BID
Nifedipine
Furosemide 5 mg OD
K supplement 2 tab BID