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Adverse Drug Reactions

Introduction

• Presented by: Gina Baugh, Pharm.D.

• Date: January 2025

• Study focuses on adverse drug reactions (ADRs), medication safety, and patient counseling.

Objectives

• Definitions: Understand adverse drug reactions, adverse events, and side effects.

• Drug Allergies: Identify drug allergies and their implications.

• Reporting Programs: Discuss reporting programs for adverse effects, including vaccines.

• Patient Counseling: Emphasize the importance of counseling patients about ADRs and side effects.

Definitions of Key Terms

Adverse Drug Events (ADEs)

• Harm resulting from adverse drug reactions and inappropriate drug use, includes:

  • Adverse drug reactions (ADRs)

  • Overdoses

• Reference: Nebeker JR et al., Ann Intern Med. 2004.

Definitions

• Adverse Event: Harm in a patient given a drug, not necessarily caused by the drug.

• Adverse Drug Reaction (ADR): Harm directly caused by a drug at normal doses.

• Side Effect: A predictable, dose-dependent effect of a drug that isn't the main therapeutic effect; may be desirable or undesirable.

Examples of Adverse Drug Reactions

Common Medications and Their Reactions

• Phenazopyridine (Pyridium®): Causes orange/red urine.

• Amiodarone (Cordarone®): May change skin color to bluish/gray.

• Bismuth Subsalicylate (Pepto-Bismol®): May cause black tongue and/or dark tarry stools.

Case Studies for Analysis

Case 1

• Patient: New hyperlipidemia diagnosis.

• Medication: Atorvastatin 10mg QD.

• Reaction: Severe muscle pain (rhabdomylosis).

Case 2

• Patient: Elderly female taking acetaminophen 650mg Q6h prn for arthritis.

• Outcome: Patient dies after 2 weeks hospitalization.

Case 3

• Patient: Using Benadryl® 25mg for allergies at night.

• Reaction: Experiences drowsiness.

Classification of Adverse Drug Reactions

Type A Reactions (Augmented)

• Predictable and dose-dependent reactions based on pharmacology.

• Severity can range from mild to severe.

Type B Reactions (Bizarre)

• Idiosyncratic and unpredictable reactions not based on drug pharmacology.

Reporting of Adverse Drug Reactions

MedWatch

• Purpose: FDA Safety Information and Adverse Event Reporting Program.

• Participants: Healthcare professionals, medical staff, pharmacists, consumers.

• Information on harmful effects and product performance.

Reporting Requirements

• Report adverse effects from:

  • Rx or OTC medications, biologics, medical devices, vaccines, cosmetics, or special nutritional products.

  • Resource: www.fda.gov/medwatch

Impact of Reporting

• Updated drug labeling information, black box warnings, and safety considerations informed to the public.

Vaccine Adverse Event Reporting System (VAERS)

Overview

• A passive reporting system established in 1990 for adverse events related to vaccines.

• Co-managed by CDC and FDA to monitor vaccine safety.

Reporting Requirements

• Healthcare providers must report serious adverse events, administration errors, and contraindications.

• Encourage reporting of any adverse events post-vaccination.

Drug Allergy

Definition

• An immune response causing abnormal reactions to medications, differing from side effects and toxicity.

Characteristics

• Symptoms: Skin rashes, hives, itching, swelling, shortness of breath.

• Severity varies significantly among individuals, with 5-10% of medication reactions classified as allergic.

Anaphylaxis

• A severe life-threatening allergic reaction characterized by symptoms like a drop in blood pressure, dizziness, and potential loss of consciousness.

Comparison of Drug Allergy and Side Effects

Summary

• Understanding ADRs, ADEs, side effects, and drug allergies is crucial.

• Pharmacists must actively counsel patients on these issues and ensure reporting of adverse events is practiced.