ADVERSE DRUG REACTIONS

Dr. Rita Grace Y. AlveroDr. Rita Grace Y. Alvero

Adverse Drug Reactions

Introduction

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

Adverse Drug Reactions

Significance

• adverse - beneficial

• significant - insignificant

• severity

• acute - chronic

• apparent - hidden

Adverse Drug Reactions

Incidence

• 30% - 1 or > ADR

- 3% severe reaction- 0.3% die

• 5% - OP basis

• extremes of age

• ♀ > ♂

• 28% past Hx

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)

Factors Affecting ADR

• Drug Related

• doses, duration

• inherent toxicity

• pharmacokinetics

• pharmacodynamics

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)

Type A

• 2 types – extension

side effect

Type B

• no formal response curve

• very small doses can elicit the reaction

• immunological

Type C

• continuous, long term

• dose and duration of therapy

Type D

• longer period of time

• carcinogenesis, teratogenecity, immunotoxicity

Type E

• withdrawal reactions

Type F

• substandard

• presence of toxic excipients

• antimicrobial resistance

• tolerance

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?

Scoring

10 – 12 - likely ADR

7 – 9 - probable ADR

4 – 6 - possible ADR

0 – 3 - unlikely ADR

Management of AD

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

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

75 year old femaleDx: 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

swollen ankleshypokalemia

gout

TxNifedipine 20 mg BIDFurosemide 2.5 mg ODRanitidine 150 mg BID

NifedipineFurosemide 5 mg ODK supplement 2 tab BID

NifedipineFurosemideK supplementsDiclofenac 50 mg TID + Allopurinol