ADVERSE DRUG REACTIONS Dr. 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 apparent - hidden severity acute - chronic

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 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