Medications ch 7 Flashcards
Types of Drug Interactions
Drug, Dietary Supplement, Disease, Laboratory
Pharmacodynamic
Changes how the drug affects the body
Pharmacokinetic
Changes how the body handles the drug
Additive
Drugs with similar effects result in those effects added together (Think addition)
SYNERGISTIC
Drug effects are amplified in combination to result in an effect that is more pronounced than just the two added together (think multiplication)
Antagonistic
Drugs counteract each other
Pharmacokinetic drug Interactions
Changes in drug absorption
Changes in drug metabolism
Changes in drug elimination
Drug indications range from smallest to greatest
- Mild
- Moderate
- Major/Severe
- Life-Threatening
Contraindications
Infers that a drug should not be used due to a heightened safety concern for a particular patient
Absolute
Avoid at all costs, risks certainly outweigh any benefit
Relative
Should be avoided unless there is a compelling benefit that will outweigh the risk
Potential Reasons
Allergy, Existing Health Condition, Drug Interaction, Genetics, Age or disease-related changes in organ function
Alcohol
- can cause additive depression of the CNS with drugs that have those effects (Opiates, benzodiazepines, muscle relaxants, etc.
- Can cause liver toxicity when combined with Acetaminophen
Antacids
Many of these can decrease the absorption of other drugs rendering them less effective
Antihistamines
Can have additive sedative effects with other sedating medications
Beta-Blockers
-Can mask symptoms of hypoglycemia from Insulin
-Can lead to Brachycardia when combined with Diltiazem or verapamil
Cabamazepine
Reduces the effectiveness of many drugs by inducing metabolism
Erythromycin
Increases the risk of side effects from many drugs by inhibiting metabolism
Fluconazole
Increases the risk of side effects from many drugs by inhibiting metabolism
Grapefruit Juice
Increases the risk of side effects from many drugs by inhibiting metabolism
Metronidazole
Inhibits metabolism of Alcohols
NSAIDS
Increase risk of bleeding with anticoagulants and antiplatelets due to additive anticoagulent effect
Phenytoin
Reduces effectiveness of many drugs by inducing metabolism
Rifampin
Reduces effectiveness of many drugs by inducing metabolism
Ritonavir
Increases toxicity of many drugs by inhibiting metabolism
St. Johns wort
Reduces the effectiveness of many drugs by inducing metabolism.
SSRIs
Can cause a potentially life-threatening condition called “serotonin syndrome”
Amiodarone
Prolongs QT interval and increases the risk for a potentially fatal heart arrhythmia called “torsades de pointes”
Antidepressants and Antipsychotics
Cause many side effects: easy for additive or synergistic effects to occur when combined with other drugs
Digoxin
Metabolized by several enzymes that are often implicated in drug interactions
Drugs for Epilepsy
Commonly metabolized by enzymes that are prone to interactions
Warfarin
-Metabolized by many enzymes that can be affected in drug interactions
-Dietary Vitamin K intake
Asthma and COPD
Beta Blocker can cause Bronchiospasm and counteract beta agonists
Chronic Kidney Disease
NSAIDs can cause kidney Failure
Heart Failure
Diltiazem, Verapamil, Pioglitazone, and some anti-arrhythmic
Hypertension
NSAIDs
Peptic Ulcer Disease
Aspirin, NSAIDs and Corticosteroids
Liver Disease
Metabolism of many drugs is impaired
Seizures
Can be precipitated by antipsychotics, bupropion, tramadol, and others
Allergy
Hypersensitivity
The result of the body’s immune system activating against a substance or drug
Allergen
Substance that triggers the allergy
Allergies can occur?
With any medication
Drug Allergy Risk
Risk of developing allergy increases with repeated exposure to a medication
Cross sensitivity
The development of an allergy to one drug may result in a similar reaction to other drugs that share similar chemical structures.
