Lecture 7 - Drug Reactions and Interactions

‭Key Topics‬ ‭‬ D ● ‭ rug interactions‬ ‭●‬ ‭Adverse drug reactions (ADR)‬ ‭●‬ ‭Review nursing actions used to prevent and reduce the effects of drug interactions‬ ‭Drug Interactions‬ ‭Drug-Drug Interactions‬ ‭‬ O ● ‭ ccur when kinetic or dynamic properties of an individual drug affect another drug‬ ‭●‬ ‭Result in unintended/intended effects‬ ‭○‬ ‭Potentiating (increased effect)‬ ‭○‬ ‭Inhibitory (decreased effect)‬ ‭○‬ ‭New response‬ ‭●‬ ‭Usually result from the patient:‬ ‭○‬ ‭Taking‬‭multiple drugs‬‭for one condition‬ ‭○‬ ‭Taking multiple drugs for multiple conditions‬ ‭ echanisms of Drug-Drug Interactions‬ M ‭Direct Chemical/Physical Interaction‬ ‭●‬ ‭Two drugs‬‭mixed in an IV‬ ‭Pharmacokinetic Drug-Drug Interactions‬ ‭●‬ ‭Absorption:‬ ‭○‬ ‭Change in gastric‬‭pH‬ ‭○‬ ‭Decreased absorption‬ ‭○‬ ‭Slowed‬‭motility‬ ‭○‬ ‭Vomiting‬ ‭●‬ ‭Distribution:‬ ‭○‬ ‭Protein‬‭binding‬ ‭●‬ ‭Metabolism‬ ‭○‬ ‭Inducers/inhibitors‬ ‭●‬ ‭Excretion:‬ ‭○‬ ‭Induct/inhibit‬‭PGP‬ ‭Pharmacodynamic Interactions‬ ‭●‬ ‭May occur at the‬‭same receptor site‬ ‭●‬ ‭2 drugs affect the same processes but at‬‭different‬‭sites‬ ‭●‬ ‭Combined toxicity‬ ‭Question:‬‭Do all drug-drug interactions result in‬‭detrimental effects?‬‭No‬ ‭Outcomes of Drug-Drug Interactions‬ ‭●‬ ‭Potentiative effect:‬ ‭○‬ ‭Positive:‬‭One‬‭drug intensifies/prolongs the effect‬‭of the other‬ ‭○‬ ‭Negative: Increases risk for ADRs‬ ‭●‬ ‭Additive effect: Provides broader coverage‬ ‭●‬ ‭Inhibitory effect:‬ ‭○‬ ‭Positive: Decreases ADRs‬ ‭○‬ ‭Negative: Decreases therapeutic effect‬ ‭■‬ ‭MAO inhibitors and tyramine‬ ‭●‬ ‭Unique new response‬ ‭Minimizing Adverse Drug-Drug Interactions‬ ‭●‬ ‭Minimize number of drugs‬ ‭●‬ ‭Medication‬‭reconciliation‬‭:‬ ‭○‬ ‭Recreational drugs‬ ‭○‬ ‭OTC drugs‬ ‭○‬ ‭Herbal supplements‬ ‭○‬ ‭Alternative therapies‬ ‭Drug-Food Interactions‬ ‭‬ ● ‭●‬ ‭●‬ ‭●‬ ‭ bsorption‬ A ‭Grapefruit juice and P450‬ ‭Toxicity and activity‬ ‭Timing‬ ‭ uestion:‬‭Grapefruit juice primarily inhibits metabolism‬‭of which family of cytochrome P450 in‬ Q ‭which location?‬ ‭a.‬ ‭CYP3A4, liver‬ b‭ .‬ C ‭ YP3A4, intestine‬ ‭c.‬ ‭CYP2A4, kidney‬ ‭d.‬ ‭CYP2D4, pancreas‬ ‭The Grapefruit Effect‬ ‭●‬ ‭Grapefruit juice inhibits metabolism of other drugs, potentially increasing plasma levels‬ ‭●‬ ‭Primarily inhibits‬‭CYP3A4‬ ‭○‬ ‭Bypass by IV administration‬ ‭●‬ ‭The grapefruit effect lasts up to‬‭three days‬ ‭Adverse Drug Reactions (ADRs)‬ ‭●‬ A ‭ ny noxious, unintended, and undesired effect that occurs at normal drug doses (World‬ ‭Health Organization, 1972)‬ ‭Question:‬‭Which patient is at highest risk for the‬‭development of an adverse drug reaction?‬ ‭a.‬ ‭A 1-month-old patient whose mother has allergies to penicilin, aspirin, and codeine‬ ‭b.‬ ‭A 16-year-old patient with multiple traumatic injuries who is taking morphine and an‬ ‭antibiotic‬ ‭c.‬ ‭A 54-year-old patient with multiple sclerosis who has been enrolled in a clinical trial of a‬ ‭new drug‬ ‭d.‬ ‭An 84-year-old patient with diabetes, heart failure, and HTN who takes seven‬ ‭prescription medications daily‬ ‭Types of Adverse Drug Reactions‬ ‭‬ S ● ‭ ide effect: A nearly unavoidable secondary drug effect produced at therapeutic doses‬ ‭●‬ ‭Toxicity: Dose-related reactions may occur due to:‬ ‭○‬ ‭Renal or hepatic impairment‬ ‭○‬ ‭Age (very young, very old)‬ ‭○‬ ‭Drug-drug or drug-food interactions‬ ‭○‬ ‭Existing underlying illness‬ ‭●‬ ‭Allergic reaction/hypersensitivity: Immune response determined primarily by the degree‬ ‭of sensitization of the immune system rather than by drug dosage‬ ‭○‬ ‭Penicillin rash‬ ‭○‬ ‭Stevens-Johnson Syndrome‬ ‭○‬ ‭Angioedema‬ ‭●‬ ‭Idiosyncratic effect: An uncommon drug response resulting from a genetic‬‭predisposition‬ ‭(Stevens-Johnson Syndrome)‬ ‭●‬ ‭Iatrogenic disease: A disease produced by drugs‬ ‭○‬ ‭Essentially identical to naturally occurring pathology‬ ‭○‬ ‭Chemotherapy and infertility‬ ‭●‬ ‭Physical dependence: Adaptation to a drug and cannot function “normally” without it‬ ‭○‬ ‭If withdrawn, abstinence syndrome is induced‬ ‭○‬ ‭Ex. narcotics‬ ‭●‬ ‭Paradoxical effect: Patient responds in a way opposite to the anticipated drug response‬ ‭●‬ ‭Carcinogenic: Cancer-causing agent‬ ‭●‬ ‭Teratogenic: The drug induces birth defects‬ ‭Severity of Adverse Drug Reactions‬ ‭‬ M ● ‭ inor:‬‭No therapy, antidote, or prolongation of hospitalization‬‭required‬ ‭●‬ ‭Moderate:‬‭Requires‬‭change‬‭in drug therapy, specific‬‭treatment, or prolongs hospital stay‬ ‭●‬ ‭Severe:‬‭Potentially‬‭life-threatening‬‭, causes permanent‬‭damage or requires intensive‬ ‭medical treatment‬ ‭●‬ ‭Lethal:‬‭Directly or indirectly contributes to the‬‭death‬‭of the patient‬ ‭Boxed Warnings‬ ‭Recognizing and Preventing ADRs‬ ‭‬ ● ‭●‬ ‭●‬ ‭●‬ ‭●‬ ‭ arrying out the 5 Rights‬ C ‭Know the side effects or ADRs associated with a drug before administration‬ ‭Assess/monitor patient response to a given drug‬ ‭Learn to recognize signs hat an ADR has occurred‬ ‭Report/document‬ ‭Identifying, Investigating, and Treating an ADR‬ ‭‬ ● ‭●‬ ‭●‬ ‭●‬ ‭●‬ ‭ as the drug given the one that was ordered?‬ W ‭Was it the correct dose and route of administration?‬ ‭Did onset of symptoms coincide with the time that drug was given?‬ ‭If the drug is discontinued, do symptoms/reactions resolve?‬ ‭Is it appropriate to restart the drug?‬ ‭Key Points‬ ‭●‬ U ‭ nderstand drug-drug and drug-food interactions and the role they place in patient safety‬ ‭and outcomes‬ ‭●‬ ‭Define adverse drug reactions (ADRs) and understand the significance of these reactions‬ ‭in the context of patient health‬ ‭●‬ ‭Describe the nursing actions used to prevent and reduce the effects of drug interactions‬