Pharm Week 2 Flashcards
Describe a True Drug Allergy.
It is an immune system mediated response.
Describe a Type I Immediate Hypersensitivity Reaction.
Acute, life-threatening allergic reaction. Multiple organ system involvement. Begins within 30 min - 2 hrs. Acute hives occurring within 2 hrs. Antibodies produced. Anaphylaxis
What are the main symptoms of a type I reaction?
Bronchoconstriction, shortness of air, edema, wheezing, angioedema, swelling of lips, face, throat, or tongue, severe hypotension, hives.
Why must patients with a type I response be continuously monitored?
Symptoms may reoccur within 6-8 hours after treatment. Must be observed for at least 12 hours.
What is polymorphism?
The occurrence of genetic variation (such as CYP450 variations)
How does genetic polymorphism affect drug metabolism?
The variant gene will encode a different protein (enzyme) which will vary the rate of metabolism - altered drug metabolism = altered patient response
What criteria of a reaction indicate a true drug allergy?
Occurs in a small percentage of patients
Reaction does not resemble the drug’s pharmacological effect
Similar to other allergic reactions
Lag time between first exposure and reaction
Reaction is reproduced even by minute doses
Reaction is reproduced by agents with similar chemical structure
Eosinophilia is present
Reaction resolves after drug is discontinued
Describe a Type IV (Delayed) Hypersensitivity reaction.
Rash, Hives, Itching
Onset of 24-48 hours after exposure
T-Cells produced.
Describe anaphylaxis?
Life threatening allergic reaction involving multiple organ systems, such as:
vasodilation, bronchoconstriction, slowed heart rate, angioedma
Occurs within 30 min - 2 hours of exposure
When might you see hives?
In a mild allergic reaction.
If they occur within 2 hours of drug administration, might be related to anaphylaxis. Do not take drug again!
If occurs 24-48 hours, just a mild reaction. no big deal
What’s the difference between an allergy and an intolerance/adverse effect?
An allergy is immunologically mediated, while an intolerance/adverse effect is just undesired effects of the drugs
How do allergies relate to dosage?
Even minute amounts will produce the allergic effects.
How do adverse effects relate to dosage?
They are dose related, meaning that the more drug given, the more bad effects you will see
Describe tolerance.
When prolonged usage of a drug produces less of an effect on the body.
More drug is needed to elicit the same effect.
Tolerance is not permanent.
Tolerance can also be built up to side effects.
Describe physical dependence.
When withdrawal symptoms occur with removal of the drug.
Describe withdrawal symptoms.
The withdrawal symptoms are the opposite of what the drug does.
Describe addiction.
Deviant behavior causing an overwhelming involvement in the use of and acquisition of a drug for euphoria.
What is a drug interaction?
The modification of the effects of one drug by the prior or concomitant administration of another drug
What are the four types of drug interactions?
- Altered GI Absorption
- Protein Displacement
- Altered Metabolism
- Synergistic Effects & Antagonistic Effects
Describe Altered GI Absorption.
A drug interaction altering the mucosa or flora of the GI tract, which in turn alters the absorption of another drug
Describe Protein Displacement.
When drugs compete for attachment to proteins, changing each other’s bioavailability.
Describe Altered Metabolism.
When drugs alter the production of enzymes that metabolize other drugs at faster or slower rates.
Describe Synergistic and antagonistic effects
When one drug may either enhance the effects of another drug, or block the effects of another drug
Describe altered intestinal flora and how it relates to drug interactions.
Some drugs (digoxin) are metabolized by intestinal flora. If the patient is given an antibiotic which wipes out the intestinal flora, the drug cannot be metabolized.
Describe altered pH and how it relates to drug interactions.
When a drug that alters the pH of the GI tract interferes with the ionization of another drug that can only be absorbed in a specific pH.
Describe transport protein interactions and how they relate to drug interactions.
Transport proteins in the GI tract can either be inhibited or accelerated by drugs, and these drugs compete for spots on this transport protein.
How do chelation interactions related to drug interactions?
Chelation is a form of strong chemical bonding which reduces their solubility and prevents absorption.
How does food affect drug interactions?
The presence or absence of food can play a significant role in the absorption of medications. It is often multifactorial and include many different processes.
What factors may alter drug metabolism?
Drugs that inhibit certain enzymes.
Drugs that induce certain enzymes.
The body’s ability to produce certain enzymes (polymorphism - CYP450 stuff)
What are three different classes of metabolizers in relation to pharmacogenetics?
Ultra metabolizers - higher than normal levels of certain isozymes, faster than expected drug metabolism
Extensive metabolizers - normally functioning metabolism
Poor metabolizers - abnormally low levels of certain isozymes, slower than expected drug metabolism
What are ways to prevent drug interactions?
Complete medication history.
Be familiar with most common interactions and adverse effects
Avoid using unnecessary drugs
Select non-interacting medications
Separate chelating or pH interacting drugs by at least 2 hours
How can grapefruit juice affect drug metabolism?
It can cause significant CYP450 suppression.
How might caffeine cause a drug interaction?
Can increase theophylline toxicity.
How can vitamin K interact with drugs?
It can decrease efficacy of Warfarin
How can alcohol interact with drugs?
It increases acetaminophen toxicity.
Can increase drowsiness.
What are different patient variables that can affect drug responses?
Pharmacokinetics Allergies Age Weight and Body Size Disease states Genetics Polypharmacy Compliance
What is Medication Adherence?
The degree to which a patient follows a treatment regimen.
What is “America’s other drug problem?”
Medication Nonadherence
How does nonadherence in the pediatric population compare to the rest of the population?
Just as common, if not higher
How might compliance be complicated in the elderly population?
Multiple medications.
Multiple prescribers.
Complex drug regimens.
What are four main sources of medication nonadherence?
Prescriber-Related (lack of trust, poor communication)
Patient-Related (difficulty understanding…)
Medication-Related (cost, complex regimens)
Pharmacy-Related (lack of trust, poor communication)
