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Flashcards in Drug Interactions Deck (27)
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Inducer

Compounds that either increase the production of an enzyme or increase the activity of the enzyme

Results in lower blood levels of the substrate

My fave been induces the metabolism of drugs at various Cyp sites

1

Inhibitor

compounds that inhibit the activity of the enzyme resulting in less drug metabolism and therefore serum job levels will increase

Example: amiodarone inhibits the metabolism of warfarin and therefore the INR increases

2

Prodrugs

Prodrugs work opposite of other drugs when it comes to an induction and inhibition

Inducers cause more of the drug to be converted to the active form and inhibitors prevent the conversion to the active drug

Example: codeine to morphine

3

P-glycoprotein

Pumps drugs back into the gut to exit out of the body

This process can also be inhibited or induced

4

Strong inhibitors of P-glycoprotein

Itraconazole, ketoconazole, verapamil, antivirals, clarithromycin, erythromycin, amiodarone, Quinidine

5

Strong inducers of P-glycoprotein

Rifampin, carbamazepine, phenytoin, St. John's wort, Ritomavir

6

Substrates of P-glycoprotein

Aliskiren, , colchicine, dabigatran, cyclosporine, digoxin, fexofenadine, posaconazole, ranolazime, rivaroxaban, saxagliptan, tacrolimus

7

Cyp inducers

Phenytoin, smoking, phenobarbital, oxcarbazepine, rifampin, carbamazepine, St. John's wort

8

Strong inhibitors of Cyp

Grapefruit, protease inhibitors, azole antifungal's, cyclosporine, cimetidine, macrolides, amiodarone, non dihydropyridine calcium channel blockers

9

Amiodarone

Decrease the doses of digoxin warfarin quinidine and procainamide by 30 to 50% when starting Amiodarone

Use lower doses of simvastatin, lovastatin, and atorvastatin

10

Digoxin

Levels increase due to decline in renal function or hypokalemia

Be careful when used with other drugs that lower heart rate such as beta blockers, verapamil, diltiazem, Amiodarone, clonidine, opioids

11

Grapefruit juice

Avoid with simvastatin, lovastatin, atorvastatin, and calcium channel blockers as it will cause an increase in the drug concentration

Grapefruit causes the drug metabolizing enzymes to be inactive

12

Lamotrigine and valproate

Combination has high risk for severe rash and requires a careful titration

13

Monoamine oxidase inhibitors

Interactions can cause serotonin syndrome, hypertensive crisis, and potentially are fatal

Monoamines that would have reduced metabolism are dopamine, epinephrine, norepinephrine, and serotonin

Do not use MAOI with SSRIs, SNRIs, TCAs tramadol, levodopa, mitazapine, bupropion buspirone, linezolid, lithium, meperidine dextromethorphan, cyclobenzaprine, triptans

14

Nonselective MAOIs

Should not be used with tyramine rich foods

Examples are aged cheese, air dried meats, wine, beer, anything aged, fermented, pickled or smoked

15

Combination of hydrocodone and tramadol

Both are metabolized by two D6 in patients with out this enzyme or those on 2D6 inhibitors would be an increased risk of respiratory depression

2D6 and inhibitors include fluoxetine paroxetine

16

Codeine

Pts with a lot of 2D6 could receive too much morphine and so could the an infant through breast milk

Conversely those with little 2D6 will have little analgesic effect

17

Oxycodone and methadone

Metabolized by 3A4 and should not be used with 3A4 inhibitors as it can be fatal

18

PDE5 Inhibitors

Contraindicated with nitrates

19

Chelation risk with quinolones and tetracyclines

Antacids, sucralfate,bile acid resins, magnesium, aluminum, calcium, iron, zinc, and multivitamins should be separated from these drugs

20

Statins

3A4 statins: atorvastatin, simvastatin, lovastatin

Drugs that inhibit 3A4 will increase risk of muscle breakdown and pain which could lead to kidney injury

21

Calcineurin inhibitors (tacrolimus and cyclosporine)

Immunosuppressants

Inhibitors of Cyp (Azoles, macrolides, SSRIs,

INDUCER: rifampin

DO NOT TAKE WITH GRAPEFRUIT JUICE

22

Bleeding risk due to additive interaction

Anticoagulants (warfarin, dabigatran, rivaroxaban, heparin)
Anti platelets (aspirin, dipyridamole, clopidogrel, prasugrel, and ticagrelor)
Others: NSAIDs, SSRIs, SNRIs, ginkgo, fish oil, primrose, vit E, garlic, glucosamine ( most of the natural products inc bleeding risk without inc INR

23

Hyperkalemia due to additive effect

Main drugs that effect potassium: spironolactone and eplerenone

Contra to use: k>5 mEq/ml, avoid use with NSAIDs

Additive effects from ACEi, ARBs, Aliskiren, amiloride, triamterene, drospirenone OC

24

CNS depression

alcohol, most pain medications, skeletal muscle relaxants, anticonvulsants, benzos, barbs, hypnotics, mirtazapine, trazodone, propranolol, clonidine, many illicit substances

25

QTc prolongation

Antiarrythmics, FQs, AG, ziprasidone, citalopram, escitalopram and others can be additive

26

Ototoxicity

Salicylates, vancomycin, AG, cisplatin, loops