Studied by 0 people
Looks like no one added any tags here yet for you.
Drug-Drug Interactions (DDIs)
reaction between two or more drugs that alters the pharmacokinetics or pharmacodynamics of the drugs
Pharmacokinetic DDIs
Affect the ADME (Absorption, Distribution, Metabolism, Excretion) of either drug.
Pharmacodynamic DDIs
causes
Altered absorption
Changes in the amount of drug that reaches systemic circulation
Altered distribution
Changes in the distribution of drugs within the body
Displacement from proteins
Two drugs that are both highly bound to plasma proteins will 'compete' for binding
Altered excretion
Changes in the elimination of drugs from the body
Altered metabolism
Changes in the metabolic processes of drugs
Enzyme induction
A drug leads to increased quantities of the CYP (usually by increasing CYP expression)
Enzyme inhibition
A drug binds tightly to the CYP and prevents metabolism of other drugs
Indirect PK DDIs
Alter ADME by changing physiologic function (i.e. cardiac output, renal function, hepatic blood flow)
CYP450 Enzymes
Primary metabolizing enzymes that play a key role in drug metabolism
CYP450 Inducers
Induce expression of the CYP, leading to increased hepatic metabolism of the drug
CYP450 Inhibitors
Inhibit access to the CYP, leading to decreased hepatic metabolism of the drug
Clinically Significant CYP Inhibitors
Includes SSRI Antidepressants, Ritonavir, Macrolide Antibiotics
Clinically Significant CYP Inducers
Includes Rifampin, Cigarette smoke, Anticonvulsants
Severity of the DDI
Severity is concentration dependent; higher dose of the CYP inhibitor or inducer leads to greater effect
Intentional and Beneficial PK DDIs
Some combination drug products take advantage of a DDI to boost the effects of one of the drugs
Drug Transporters
Transporters exist in the intestine, liver, kidneys, bile ducts, placenta, and CNS endothelium
P-glycoprotein (Pgp)
Best studied transporter involved in drug transport
Transporter Interaction Example
Rosuvastatin uses OATP transporters for hepatic uptake; Cyclosporine inhibits OATP transporters
Pharmacodynamic DDIs
Interactions that affect the therapeutic effects of drugs
Synergistic Effects
Overall effect of the drug combination is greater than the sum of the effects of the two drugs individually
Additive Effects
Overall effect caused by the drug combination is the sum of the pharmacologic effects of each individual agent
Antagonistic Effects
Effect of one drug is decreased by the other drug
Pediatric Body Composition Changes
Higher total body water and lower body fat affect drug handling in pediatrics
Geriatric Body Composition Changes
Lower total body water and higher body fat affect drug handling in geriatrics
Polypharmacy
The regular use of 5 or more medications, common in the geriatric population
eGFR
Estimated glomerular filtration rate, used to stage kidney function/disease
CrCl
Creatinine clearance, used for making dose adjustments in medications based on kidney function
Higher incidence of chronic medical conditions
Cardiovascular disease, diabetes, osteoporosis, autoimmune disorders.
Consequences of polypharmacy
What are the consequences of polypharmacy?
Risk of side effects
Increased likelihood of adverse effects from medications.
Risk of drug-drug interactions
Increased chance of negative effects when multiple medications are taken together.
Risk of medication errors
Increased likelihood of taking medication at the wrong time, in the wrong quantity, etc.
Prescribing cascade
A situation where a medication is prescribed to treat the side effects of another medication.
Beers Criteria
A comprehensive list of medications that may be inappropriate for patients over 65 years old.
Economic factors
Financial considerations that affect medication access and adherence in the elderly.
Functional factors
Physical abilities or limitations that impact medication management in older adults.
Sociocultural factors
Social and cultural influences that affect the health and medication practices of the elderly.
Food vs meds
The consideration of food intake in relation to medication schedules.
Vision loss
Impairment in sight that can affect medication management.
Cheaper OTC vs $$$ Rx
The choice between over-the-counter medications and expensive prescription drugs.
Loss of social support
The absence of a support system that can assist with medication management.
Cognitive dysfunction
Impaired cognitive abilities that can lead to difficulties in managing medications.
Use of outdated meds
The continued use of medications that may no longer be appropriate or effective.
Loss of motivation
Decreased willingness or ability to manage medications properly.
Musculoskeletal disorders
Physical conditions that can affect the ability to manage medications.
Sharing meds
The practice of taking someone else's medication, which can lead to risks.
Proton-Pump Inhibitors (PPIs)
Medications used for the treatment of gastric reflux and GI ulcers.
Antiarrhythmics
Medications used to restore normal sinus rhythm and treat arrhythmias.
Anticoagulants
Medications that prevent clotting and reduce the risk of stroke and heart attack.
Antihistamines
Medications used to treat allergies.
Antihypertensives
Medications that lower blood pressure.
Anti-Parkinson's Agents
Medications used to treat Parkinson's disease.
Antipsychotics
Medications used for the treatment of psychotic disorders and mood disorders.
Anxiolytics
Medications used to treat anxiety disorders.
Corticosteroids
Medications used to treat inflammatory or autoimmune conditions.
Diuretics
Medications used to treat fluid retention.
Hypoglycemics & Insulin
Medications used for the treatment of diabetes.
Opioids
Medications used to treat pain.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
Medications used for the treatment of pain and fever.
Beta-Agonists for Respiratory Conditions
Medications used to treat asthma and COPD.
Tricyclic Antidepressants
Medications used for the treatment of depression and insomnia.
Management of Polypharmacy
Strategies to reduce the number of medications prescribed to a patient.
Medication Safety Tips for Geriatrics
Guidelines to ensure safe medication practices for elderly patients.
Vision Impairments
Conditions that affect sight, requiring adaptations in medication management.
Dexterity Issues
Physical limitations that affect the ability to handle medications.
Memory Impairments
Cognitive challenges that can hinder medication adherence.
Altered absorption
Changes in the amount of drug that reaches systemic circulation.
Altered distribution
Displacement from proteins or changes in bioavailability due to pH, binding, or GI motility.
Altered excretion
Changes in the elimination of drugs from the body.
Altered metabolism
Changes in the breakdown of drugs, including enzyme induction and inhibition.
Indirect PK DDIs
Alter ADME by changing physiologic function (i.e. cardiac output, renal function, hepatic blood flow).
CYP450 Enzymes
Primary metabolizing enzymes that can be substrates, inhibitors, or inducers.
CYP450 Inducers
Increase the expression of the CYP, leading to faster metabolism of the drug.
CYP450 Inhibitors
Decrease the metabolism of drugs by inhibiting access to the CYP.
Clinically Significant CYP Inhibitors
Examples include SSRI antidepressants, Ritonavir, Macrolide antibiotics.
Clinically Significant CYP Inducers
Examples include Rifampin, cigarette smoke, and St. John's Wort.
Polypharmacy
The regular use of 5 or more medications.
Special Populations
Groups such as pediatrics and geriatrics that may have different drug handling characteristics.
Pediatric Body Composition Changes
Higher total body water and lower body fat and muscle mass affect drug handling.
Geriatric Body Composition Changes
Lower total body water and higher body fat affect drug handling in older adults.
eGFR
Estimated glomerular filtration rate, a key measure of renal function.
CrCl
Creatinine clearance, used for making dose adjustments in medications based on kidney function.
Potentially Inappropriate Medications (PIMS)
Medications that may be inappropriate for patients over 65 years old, according to Beers Criteria.
Proton-Pump Inhibitors (PPIs)
Used for treatment of gastric reflux and GI ulcers, examples include Omeprazole and Pantoprazole.
Antiarrhythmics
Used to restore normal sinus rhythm, examples include Amiodarone and Digoxin.
Anticoagulants
Prevent clotting and reduce the risk of stroke, examples include Warfarin and Rivaroxaban.
Antihistamines
Used to treat allergies, examples include Diphenhydramine and Cetirizine.
Antihypertensives
Lower blood pressure, examples include Lisinopril and Amlodipine.
Anti-Parkinson's Agents
Used to treat Parkinson's disease, examples include Carbidopa/levodopa and Benztropine.
Antipsychotics
Used for treatment of psychotic disorders, examples include Risperidone and Haloperidol.
Anxiolytics
Treat anxiety disorders, examples include Benzodiazepines.
Corticosteroids
Used for treatment of inflammatory or autoimmune conditions, examples include Prednisone.
Diuretics
Treat fluid retention, examples include Furosemide and Hydrochlorothiazide.
Hypoglycemics & Insulin
Used for treatment of diabetes, examples include Glipizide and Insulin glargine.
Opioids
Used to treat pain, examples include Oxycodone/acetaminophen and Tramadol.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
Used for treatment of pain and fever, examples include Ibuprofen and Celecoxib.
Beta-Agonists for Respiratory Conditions
Used to treat asthma/COPD, example includes Albuterol inhaler.
Note 
Flashcard (22)