Drug Interactions - Quiz 2 Flashcards

1
Q

What is pharmacodynamics?

A

The effect or change that a drug has on the body

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2
Q

What drugs are affected by coadminstration with polyvalent cations?

A

Quinolones, tetracyclines, levothyroxine, bisphosphonates

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2
Q

What is pharmacokinetics?

A

The effect the body has on the drug

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3
Q

What is the primary enzyme expressed in the liver?

A

CYP450

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3
Q

What drug blocks the renal excretion of penicillin?

A

Probenacid

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4
Q

What are prodrugs?

A

Inactive drug that is converted by CYPs to an active drug

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5
Q

What are the benefits of prodrugs?

A
  1. INcrease bioavailability
  2. Prevent drug abuse
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6
Q

What is the activity of prodrugs in the presence of CYP inhibiutors and inducers?

A

Inhibitors: concentration of active drug decreases
Inducers: concnetration of active drugs inrease

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7
Q

What are the most common CYP inhibitors?

A

Grapefruit
Protease Inhibitors
Azole
Cyclosporine, cobicistat
Macrolides (clarithromycin and erythomycin)
Amiodarone
Non-DHP CCBs (diltiazem and verapamil)

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8
Q

What are the common CYP inducers?

A

Phenytoin
Smoking
Phenobarbital
Oxcarbazepine
Rifampin
Carbamazepine
St John’s wort

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9
Q

How long in the lag time when an inducer has been discontinued?

A

2-4 wks

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10
Q

Common Pgp substrates?

A

Anticoagulants: apixaban, rivaroxaban
CV drugs: digoxin, diltiazem, verapamil
Immunosuppressants: cyclosporine, tacrolimus
Colchicine

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11
Q

Common pgp inducers?

A

Carbamazepine, phenobarbital, phenytoin, rifampin, St Johns

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12
Q

Common pgp inhibitors?

A

CV: amiodarone, diltiazem, verapamil
HIV: cobicistat, ritonavir
Cyclosporine

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13
Q

When adding warfarin to amiodarine what do you need to adjust? Vice versa?

A

Warfarin at low dose ≤5 mg

Decrease warafarin dose by 30-50% depending on INR

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14
Q

What is the cause of amiodarone and warfarin interaction?

A

Amiodarone is a CYP2C9 inhibitor increasing risk for bradycardia (Check for other drugs: beta blockers, clonidine, diltiazem, verapamil for decreased HR)

Reduse PO digoxin 50% when adding on amiodarone

15
Q

What is the cause of amiodarone and digoxin interaction?

A

Amiodarone inhibits pgp

16
Q

What electrolytes are decreased by loop diuretics? digoxin?

A

K, Mg, Ca, Na

Decreased K and Mg, increased Ca

17
Q

What are drugs that decrease HR? How should you monito?

A

Amiodarone,digoxine, clonidine, beta blockers, diltiazem, verapamil

Monitor HR: 60-100 BPM

18
Q

What statins are increaed with conmittant use of strong CYP3A4 inhibitors? How do you address interaction?

A

Lovastatin, simvastatin, atorvastatin

Non-CYP statins: pitavastatin, pravastatin, rosuvastatin

19
Q

What enzyme metabolizes waraafarin?

A

CYP2C9

Inhibitors-> Increased levels -> Increased INR and bleeding risk
Inducers -> derease levels -> decreased INR and increases clotting risk

20
Q

What should not be taken with CYP3A4 substrates?

A

Grapefruit juice

21
Q

How do you does lamotrigine and valproate together?

A

Starter kit initiates lamotrigine with lower doses and tritates every 2 wks

22
Q

MOA inhibitors increases what catecholamines?

A

Epi, NE, DA, 5-HT

Hypertensive crisis and serotonin syndrome

23
Q

Counseling points of MAOIs?

A

2 wk wash out period when switching between MOAI and serotonergic agents
* 5 weeks if initiating fluoxetin

Avoid tyramine containig foods (aged cheeses, dried meats, sauerkraut)

24
Q

What opioid are CYP3A4 substrates?

A

Fentanyl, hydrocodone, oxycodone, methadone

25
Q

Smoking induces what CYP enzyme?

A

1A2

26
Q

What drugs increase risk for bleeding?

A
  1. Anticoags
  2. Antiplatelets
  3. NSAIDs
  4. SSRIs, SNRIs
  5. Garlic, ginger, gingko, ginseng, glucosamine
27
Q

Drugs that cause kyperkalemia?

A
  1. RAAS inhibitors
  2. Potassium sparing diuretics (amiloride, triamterene)
  3. salt substitute, calcineurin inhibiotrs
28
Q

QT prolongationcan lead to ?

A

Torsades de pointes

29
Q

q

What are the ADRs asscoaited with CNS depression?

A
  1. Somnolence
  2. DZ
  3. Confusion
  4. Cognitive impairment
  5. Altered consciousness
  6. Falls
30
Q

What medications should not be taken together to avoid CNS depression?

A
  1. Opioids
  2. Benzos
  3. Alcohol
31
Q

Drugs that cause ototoxicity?

A
  1. Aminoglycosides
  2. Cisplatin
  3. Loops
  4. Aspirin
  5. Vancomycin
32
Q

Drugs that cause nephrotox?

A
  1. Aminoglycosides, vanc, amphotericin B, polymixins
  2. Cisplatin
  3. CIs
  4. Loops
  5. NSAIDs
  6. Contrast dyes (radiographic)
33
Q

Anticholinergic toxicity is moreconcerning for who?

A

Elderly

34
Q

Drugs that increase risk for orthostasis>

A

PDE5-I
with
CYP3A4 inhibotrs, Nitrates, or a-1 blockers