8/8/2016. Overview. Back to Basics: Immunology. Adverse Reactions to Drugs: Dispelling Myths

Transcription

1 Adverse Reactions to Drugs: Dispelling Myths Allison Ramsey, MD NPA Annual Conference September 30, 2016 Overview Review of types of hypersensitivity reactions Penicillin allergy IV contrast allergy Local anesthetic allergy Inactive drug ingredient (excipient) allergy Food allergy and drug allergy Corticosteroid allergy Back to Basics: Immunology 1

2 Clinical Presentation / Common Offenders Reaction Type Presentation Causes Timing Common Offenders Type 1 (IgE) Hives, itching, Drugs Fast: Minutes to Antibiotics, NSAIDs, cough, wheezing, hypotension, GI symptoms Foods Latex Venom IT hours latex Type 2 (AIHA) Anemia Drugs Days Penicillin, sulfa Type 3 (Serum sickness) Type 4 (T cell) Rash, urticaria, lymphadenopathy fever, joint pain Rash, blistering, secondary organ involvement Drugs Antivenin Drugs Topicals 1-3 weeks Penicillin, cephalosporins biologics Variable (days to weeks) Antibiotics, local anesthetics, topical antibiotics, antiepileptics, PPIs Type 1: Urticaria Type 1: Angioedema 2

3 Type IV: Classic drug rash Type IV: Severe cutaneous reaction Stevens Johnson Syndrome Type IV: Toxic epidermal necrolysis 3

4 What constitutes a drug allergy? A) Any negative symptoms a patient experiences after taking a drug B) A family history of allergy to the drug C) An immunologically-mediated response to a drug D) Inability to pronounce the drug name or recall the commercial on which it was advertised Definitions Adverse drug reaction: all unintended pharmacological effects of a drug except therapeutic failures, intentional overdose, abuse of the drug, or errors in administration Drug intolerance: undesirable pharmacologic effect of the drug at low or usual doses without abnormal metabolism, excretion, or bioavailability. Immune mechanisms not thought to be involved, but other mechanism not explained. Drug allergy: Immunologically mediated response to a drug and/or formulation in a sensitized person Solensky and Khan et al Annals of Allergy Asthma & Immunology. High yield history points Age reaction occurred Patient description of symptoms Red flag symptoms: Blistering, mucous membrane involvement, fever, joint symptoms, need for urgent medical attention, hospitalization Tolerance of related medications 4

5 True or False Skin testing is informative for most IgE-mediated drug reactions FALSE Drug Skin Testing Skin testing best validated for penicillin May be helpful for platinum based chemotherapy agents Can perform for other medications Not validated No population data Positive helpful, negative not helpful Penicillin allergy skin prick testing 5

6 Skin testing intradermal test 10% of the population reports a penicillin allergy, but only 1% of these patients are allergic TRUE Macy Perm J. Spring;13(2):

7 Interpretation of penicillin skin test Positive penicillin skin test: 50/50 chance of reaction Avoid penicillin Negative penicillin skin test: Risk approximately that of the baseline population for an IgE-mediated reaction Does NOT address other types of reactions Solensky and Khan et al Annals of Allergy Asthma & Immunology. The cross reactivity between penicillin and cephalosporins is 15% FALSE Penicillins and cephalosporins 2% risk of cross reactivity in skin test positive patients Caveat is that this cross reactivity has been anaphylaxis Risk lower for higher generation cephalosporins Skin test negative patients can receive safely Possible opportunity for graded challenge Direct challenge in low risk patients Solensky and Khan et al Annals of Allergy Asthma & Immunology. 7

8 Patients with shellfish allergy should avoid IV contrast FALSE 8

9 Seafood allergy and radiocontrast Majority of reactions to radiocontrast not IgE-mediated Food allergy is IgE-mediated IgE against PROTEINS in crab, shrimp, lobster Iodine is not even a protein Beaty et al Am. J. Med. 121:2. 158e2-e4. Iodinated Contrast Reaction Incidence: 1-3%, possibly higher Risk Factors: Female gender, asthma, previous reaction Direct histamine release, not IgE mediated Pretreatment regimens effective Local anesthetic allergy is common FALSE 9

10 Local anesthetic allergy True IgE-Mediated Allergy : 0.97% A reaction to a drug is due to inactive ingredients in the drug about half the time FALSE Drug Excipients Inert substance Added for kinetics, absorption, stability, palatability, appearance 2014 review on subject Carboxymethylcellulose, benzyl alcohol, povidone, sodium benzoate, sulfites ***Case reports, small case series only*** Barbaud, A Immunol Allergy Clin N Am. 34:

11 Excipient allergy is rare, but dye allergy is common FALSE Dye Allergy Only 1 patient out of 102 patients reacted Facial swelling and pruritic facial lesions Other dye allergy: scattered case reports only Provocation challenges recommended People with food allergy generally have a low risk of reacting to medications due to food ingredients TRUE 11

12 Food allergy and medication allergy Propofol Egg question largely unsubstantiated Fish oil Highly refined, fish-allergic patients should tolerate Lactose-containing medications Dry powder inhalers, methylprednisolone (case reports) Soy lechitin Inhaler question unsubstantiated Kelso, J JACI. 133: Immediate (IgE-mediated) reactions to corticosteroids occur TRUE Corticosteroid Allergy But they are rare!!!! Patel and Bahna Annals of Allergy, Asthma, Immunol. 115:

13 If a patient is truly allergic to a drug, an allergist can trick the immune system into tolerating the drug for the desired course of treatment TRUE Temporary Induction of Drug Tolerance Example protocol for trimethoprim/sulfamethoxazole Solensky and Khan et al Annals of Allergy Asthma & Immunology. Questions? Thank you! allison.ramsey@rochesterregional.org 13