Drug interactions

Question 1

What is a DI?

Answer 1

When the effects of one drug are altered by another substance like drugs, food, herbals, alcohol, nicotine, and disease states.

Question 2

What is a DDI?

Answer 2

when a substance precipitating the change in effect is a drug

Question 3

What are the most common DDI causing drugs?

Answer 3

NSAIDs and Digoxin and Warfarin

Question 4

What are high risk conditions for DDIs?

Answer 4

aplastic anemia, asthmas, cardiac arrhythmia, diabetes, seizure disorders, hepatic disorders, hypothyroid, autoimmune diseases, infection, respiratory disorders.

Question 5

What are the 4 high risk populations of DDI?

Answer 5

Elderly, critical care patients, patients with complications, and surgical patients.

Question 6

What is a PK DDII?

Answer 6

It influences the disposition of a drug in the body and effects ADME. They frequently cause marked shifts in serum drug concentrations and altar clinical response.

Question 7

What is a PD DDI?

Answer 7

differences in drugs response at given drug concentrations in the plasma. It happens at the levels of binding sites or secondary messenger systems. Usually associated with synergism, antagonism, or altered transport across cell membranes. They affect organ systems and receptor sites.

Question 8

What are examples of causes of DDIs that can happen prior to administration?

Answer 8

a change in absorption caused by; chelating agents, changes in gastric PH, alterations in GI motility, modify of PGP, alterations in intestinal flora from antibiotic use

Question 9

How can phenytoin become a DDI when mixed with dextrose?

Answer 9

a precipitate forms and the phenytoin becomes an insoluble salt that is no longer dispersed throughout the solution and becomes ineffective

Question 10

What happens when aminoglycosides are mixed with beta lactam antibiotics?

Answer 10

It reduces antibiotic efficacy

Question 11

What drugs do iron, magnesium, calcium, and aluminum decrease the absorption of?

Answer 11

These are chelating agents, and it affects fluoroquinolones, and tetracycline. They should be given at least two hours apart from chelating agents.

Question 12

What drugs do cholestyramine bind to and decrease the absorption of?

Answer 12

Raloxifene, thyroid hormones, and digoxin

Question 13

what drugs can PPI interact with

Answer 13

it neutralizes the stomach acid and drugs that require acid for absorption will be decreased like, ketoconazole, digoxin, iron salts, and ampicillin

Question 14

How do laxatives decrease the absorption of certain drugs?

Answer 14

It causes an increase in GI motility and drugs that require a longer absorption time will be absorbed too fast.

Question 15

What PGP drugs are affected by blocking of pgp?

Answer 15

steroids and digoxin, and blocking can cause increased toxicity of those drugs

Question 16

What drugs do antibiotics decrease the absorption of?

Answer 16

Oral contraceptives by decreasing gut flora

Question 17

What is an example of two drugs that fight for the same binding site and become displaced?

Answer 17

Warfarin and diclofenac, results in a increased level of warfarin and could cause serious affects like bleeding.

Question 18

What are CYP 450 enzyme inducers

Answer 18

Stimulates enzyme production which leads to increased metabolism and decreased drug effect

Question 19

What are CYP 450 inhibitors?

Answer 19

inhibits enzyme production which can leads to decreased drug metabolism and increased drug effect & toxicity.

Question 20

What are examples of enzyme inducers?

Answer 20

barbiturates, carbamazepine, griseofulvin, phenytoin, and rifampin.

Question 21

Is ritonavir a enzyme inhibitor or inducer?

Answer 21

It could be both depending on the situation.

Question 22

What class of drugs are most susceptible to enzyme induction?

Answer 22

CYP3A4 and CYP2C9

Question 23

Inhibitors of which class increases theophylline toxicity?

Answer 23

CYP1A2

Question 24

Inhibitors of which class increase phenytoin oral anticoagulation toxicity?

Answer 24

CYP2C9

Question 25

What is an example of two drugs that use the same transport system to be secreted from renal tubule cells?

Answer 25

methotrexate and ibuprofen- could result in decreased excretion of methotrexate and cause toxicity.

Question 26

Alteration in urine PH affect which two reabsorption pathways?

Answer 26

active and passive tubular reabsorption

Question 27

if the pH of the urine is _______ the reabsorption of acidic drugs is reduced

Answer 27

alkaline

Question 28

if the pH of the urine is _______ the reabsorption of basic drugs is reduced

Answer 28

acidic

Question 29

what two types of drugs alkalinize the urine and decrease the rate of salicylate reabsorption and increase its excretion?

Answer 29

Thiazide diuretics and sodium bicarb

Question 30

What are synergistic effects?

Answer 30

combined drug effects that produce a greater response than the combined two drugs 1+1=3

Question 31

What are additive affects?

Answer 31

combined drug effects produce a reaction that is equal to the combination of the drugs (also called summative) 1+1=2

Question 32

What is potentiation?

Answer 32

One drug increases the effect of the other. It may result in increased toxicity.

Question 33

Beta blockers, ace inhibitors, and nitrates can all reduce BP causing a combined _____ effect

Answer 33

synergistic

Question 34

What are two examples of Additive drug interactions?

Answer 34

combinations of drugs that prolong the QTc interval create ventricular arrythmias or combining drugs with hyperkalemic effects leading to hyperkalemia

Question 35

What are two examples of antagonistic drugs

Answer 35

NSAIDS may inhibit antihypertensive drugs like ACE inhibitors OR benzos inhibited by theophylline

Question 36

What is a beneficial antagonist?

Answer 36

Naloxone used in opioid overdose

Question 37

What is a harmful antagonist?

Answer 37

a beta 1 agonist will have reduced bronchodilation with a non-selective beta blocker

Question 38

What is a prescribing cascade?

Answer 38

When ADRs of a drug aren't recognized and a second drug is prescribed to tx the side effects. It may increase the risk for new ADRs or increase the severity of the same ADR

Question 39

What is combined toxicity?

Answer 39

When two or more drugs have a toxic effect on the same organ and increase the risk for organ damage

Question 40

When penicillin, tetracycline, erythromycin, levodopa, and phenytoin and digoxin are taken with food it ________ the absorption

Answer 40

decreases

Question 41

When spironolactone, Griseofulvin, and itraconazole are taken with food it _______ the absorption

Answer 41

Increases

Question 42

Taking ketoconazole with cola products leads to-

Answer 42

prolonged serum levels of the ketoconazole

Question 43

What foods are high in vitamin and decrease warfarin effects?

Answer 43

Alfalfa tabs, broccoli, brussels sprouts, cabbage, cauliflower, green leafy vegetables, green tea, liver, soybeans, veggie oils, and watercress.

Question 44

What foods and vitamins cause increased levodopa metabolism and have decreased blood levels of dopamine and Anti parkinsonism effects

Answer 44

Vitamin B6, avocados, beans, peas, sweet potatoes. bacon, beef liver, pork, tuna

Question 45

What can calcium interact with to do reduce bioavailability?

Answer 45

Fluoroquinolone antibiotics and phenytoin- decreased antibiotic activity and causes a loss of seizure control

Question 46

What drugs cause weight gain when patients with diabetes take them?

Answer 46

TCAs, mirtazapine, paroxetine, clozapine, olanzapine, quetiapine, risperidone, lithium, valproic acid

Question 47

What drugs should you avoid if you have hypertension?

Answer 47

Venlafaxine, duloxetine, and bupropion because they increase BP

Question 48

What drug should you avoid if you have epilepsy?

Answer 48

Bupropion

Question 49

What drugs should you avoid with Parkinson's disease?

Answer 49

Risperidone, and conventional antipsychotics

Question 50

What drugs should you avoid with Alzheimer's disease?

Answer 50

Antipsychotics, TCAs, Paroxetine, clozapine, and olanzapine

Question 51

What drugs should you remember are high risk for DDIs?

Answer 51

anticonvulsants, antibiotics, antidepressants, digoxin, warfarin, amiodarone

Question 52

What resources can you use to check for DDI?

Answer 52

epocrates, pharmacist, colleague, computerized alert system, and package inserts

Question 53

Where should you report ADE?

Answer 53

MedWatch for serious reactions and drug manufacturer for nonserious reactions

Question 54

Where can you report vaccine ADE?

Answer 54

VAERS

Question 55

Describe the process that is required by the Food and Drug Administration to move a drug from a candidate molecule to a drug approved for clinical use

Answer 55

IND app-> Clinical trials -> NDA submission and approval

Question 56

Describe a rational course of action for the situation where there is a high probability that two or more drugs of a patient’s regimen are interacting with resultant deleterious effects.

Answer 56

The first step is to avoid DDI’s whenever possible: consider who are high-risk patients; which drugs are considered high-risk for DDI’s; report any known or suspected DDI to the pharmacy and appropriate organization

Question 57

Explain what is meant by “Post-Market Surveillance” and the role of advanced practice nurses in this process

Answer 57

Phase IV, The FDA seeks voluntary reporting of ADRs from healthcare professionals on MedWatch. It is important for detecting ADRs that are uncommon and unlikely to be found in clinical trials