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Flashcards in Ger 7 Drug Interactions Deck (69)
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What is a drug-drug interaction?

The effect that one drug has on another


What are the 2 types of drug-drug interactions?

1. Pharmacokinetic (what the body does to the drug)
2. Pharmacodynamics (what the drug does to the body)


What is a pharmacokinetic drug interaction?

The effects of one drug on the absorption, distribution, metabolism, or excretion of another drug


What can pharmacokinetic drug interactions result in?

Changes in serum drug concentrations and might change clinical response


What is most frequently involved in pharmacokinetic drug interactions?

1. CYP P450
2. P-Glycoprotein
3. Organic anion transporters


What is a pharmacodynamic drug interaction and what is the outcome?

-Related to the pharmacological activity of interacting drugs
-The outcome is an amplification or decrease in the therapeutic effects or side effects of a specific drug


What are other types of drug interactions?

1. Drug-Food
2. Drug-Alcohol
3. Drug-Herbal Product
4. Drug-Nutritional Status
5. Drug-Disease or Drug-Patient interactions
*Review Chart in Objectives for Specific Examples


When do drug-disease or drug-patient interactions occur?

They take place when a drug has the potential to exacerbate and underlying disease or medical disorder


What are the 3 new groups of patients at risk for drug-drug interactions?

1. Organ transplant
2. Mental-health problems
3. HIV patients that survived to late life


What are 3 common drug interactions?

1. Patients taking drugs with a narrow therapeutic index
2. Patients taking drugs that are substrates, inhibitors, or inducers of CYP450 isoenzymes
3. Drug-Disease Interactions


What are examples of drugs with a narrow therapeutic index involved in drug-drug interactions?

1. Digoxin
2. Phenytoin
3. Warfin


What are examples of drugs that are substrates, inhibitors, or inducers, of CYP450 isoenzymes commonly involved in drug-drug interactions?

1. CYP3A4
2. CYP2D6


What diseases are common to cause drug-disease interactions?

1. Constipation
2. Dementia
3. Postural Hypotension


When are complex interactions seen?

Patients with 9 or more drugs and 5 or more comorbidities
-Although the choice of drugs individually makes sense to treat the patient, the total combination could yield unwanted results (drug-drug interactions and drug-disease interactions)


What is the increased risk of drug interactions due to in elderly patients?

1. Patient factors
2. Prescriber factors
3. Difficulties within the health-care system (Inefficient communication between health professionals and patients)
-All of these need to be considered for prescribing medications for elderly patients


What are patient factors that can increase the risk of drug interactions in elderly patients?

Age related pharmacokinetic and pharmacodynamic changes (these can potentially increase the risk of adverse effects from drug interactions)


What 3 things decrease as you age than can affect pharmacokinetics and pharnacodynamics?

Cellular, organ, and systems reserves


What results in heterogeneity between people as they age?

Individual genetics, lifelong living habits, and environment


Will all 85 year old women react to the same specific dose of a drug in the same way?



Can you use a prototypical male (80kg) that models adult medicine in prediction of treatment for the elderly population?



What is a prescriber factor?

-Physicians are often not aware of all the drugs that the elderly patients are taking
-Physician was unaware that the patient was not following the doctor's orders by not taking a drug prescribed to them


What is a big problem physicians face?

Incomplete documentation of past medical history and active drug profile


What happens as a result of incomplete documentation of past medical history and active drug profile?

EM physicians aren't considering interactions as a possible cause of presenting complaints of patients
--> This results in a typical presentation of disease or vague presenting complaints such as confusion, falls, urinary incontinence, and weakness masking or confusing the detection of drug interactions


What are 2 of the difficulties within the health system?

1. Receive prescriptions from several physicians
2. Take prescriptions to be filled at many pharmacies


What is the risk of receiving and inappropriate drug combination directly related to?

The number of physicians prescribing drugs for that elderly patient


Describe cascading interactions.

-Prescribing cascade begins when an adverse drug reaction is misinterpreted as a new medical disorder
-Another drug is then prescribed, and the patient is placed at risk of developing additional adverse effects related to this potentially unnecessary treatment
-This can produce pharmacokinetic or pharmacodynamic interactions


With regards to cascading interactions, what are patients at increased risk of receiving who had dementia and were dispensed cholinesterase inhibitors?

An anticholinergic drug to manage new urinary incontinence


What is usually diagnostic with regards to drug interactions?

A complete and careful history of the onset of a patient's symptoms and recent treatment changes are usually diagnostic


What is the best elderly patient care?

Elderly patients usually do better when their care is managed by multidisiplinary team that practives the principles of geriatric care


What is the optimum drug management tearm?

A physician (geriatrician), nurse, and pharmacist (communication between these professionals is crucial for success)