ADVERSE DRUG REACTIONS Dr. Rita Grace Y. Alvero. Adverse Drug Reactions Introduction.

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