NAPLEX 2026 - Drug interactions

P-GP Common substrates:

Anticoagulants: ______, ______

CV drugs: ___, ___, _____

Immunosuppressants: ____, ______

Others: _____

Anticoagulants: rivaroxaban, apixaban

CV drugs: diltiazem, verapamil, digoxin

Immunosuppressants: cyclosporine, tacrolimus

Others: colchicine

P-GP Common Inducers: (decrease concentration)

similar to CYP3A4

Anti-epileptics: ___, ____, ________

Other: ____, _______

Anti-epileptics: Carbamazepine, phenobarbital, phenytoin

Other: rifampin, st john’s wort

P-GP Common Inhibitors: (increase concentration)

similar to CYP3A4

CV drugs: ___, ____, ________

HIV drugs: _____, _____

Immunosuppressants: ____, _______

CV drugs: verapamil, diltiazem, amiodarone

HIV drugs: ritonavir, cobicistat

Immunosuppressants: cyclosporine

CYP3A4 substrates

Analgesics: ____, _____, ____, _____

Anticoagulants: _____, ____, _____

CV drugs: ___, ____, ____, ____

Immunosuppressants: ____, ____, ____

Statins: ____, _____, _____

HIV drugs: ___, ____, _____

PDE-5 inhibitors: sildenafil, tadalafil, vardenafil, avanafil

Analgesics: fentanyl, methadone, hydrocodone, oxycodone

Anticoagulants: s-warfarin, rivaroxaban, apixaban

CV drugs: amiodarone, diltiazem, verapamil, digoxin

Immunosuppressants: cyclosporine, tacrolimus, sirolimus

Statins: atorvastatin, lovastatin, simvastatin

HIV drugs: cobicistat, ritonavir, NNRTIs

PDE-5 inhibitors: sildenafil, tadalafil, vardenafil, avanafil

CYP3A4 inducer

1. ___, ____, ___, _____

2. ____

3. ____

4. ____

1. Carbamazepine, oxcarbazepine, phenobarbital, phenytoin

2. Rifampin

3. Smoking

4. St John wort

CYP3A4 inhibitor

MADVAP + (Cyclosporine)

Macrolides, azoles, diltiazem, verapamil, amiodarone, protease inhibitors (and cobicistat and ritonavir)

CYP2C9 substrate

S-Warfarin

CYP2C9 inducer (same as CYP3A4)

Carbamazepine, phenobarbital, phenytoin, st john wort, smoking

CYP2C9 inhibitor

BAMIF

Bactrim, amiodarone, metronidazole, itraconazole (and other azoles), FQs

CYP2C19 PPIs

esomeprazole, omeprazole

CYP2D6 SUBSTRATES

___, ____, ____

CYP2D6 INHIBITORS

____, ____, ___, ___

meperidine, tramadol, codeine

Amiodarone, duloxetine, paroxetine, fluoxetine

CYP1A2 SUBSTRATES

___, ____

CYP1A2 INHIBITORS INDUCERS (same as CYP2C9, CYP3A4)

CYP1A2 INHIBITORS

____, ____

theophyline, warfarin

ciprofloxacin, fluvoxamine

Opioids with serotonergic activity (contraindicated within 14 days of MAO-I)

___, ____, ____, ____ (there is a risk with any but particularly these)

meperidine, fentanyl, methadone, tramadol, codeine

MAO inhibitors

Antidepressants: _____, _____, _____

Selective MAO-Is: _____, _____

Others: _____, _____

Antidepressants: isocarboxazid, phenelzine, tranylcypromine

Selective MAO-Is: selegeline, rasagiline

Others: linezolid, methylene blue

Serotonin syndrome can cause altered mental status such as ___ and ____ as well as neuromuscular excitation like ___ and ____. Avoid using serotonergic drugs together, but if used the doses should be within recommended ranges. A washout period is ____ weeks or ____ weeks for drugs with a longer duration of action such as _____.

agitation and delirium ; rigidity and seizures ; 2 weeks ; 5 weeks ; fluoxetine

Amiodarone ______ CYP____ which would usually ____ warfarin. If using warfarin 1st and adding amiodarone _______.

inhibits CYP3A4 ; metabolize ; reduce warfarin dose by 30-50%

Amiodarone inhibits ____. Digoxin is a substrate of it, and inhibition of this means that drugs will not be pumped back into the stomach for excretion. More circulation, more toxicity. If using digoxin first and adding amiodarone then _____.

P-GP ; reduce digoxin 50%

Which statins are contraindicated with strong CYP3A4 inhibitors?

Simvastatin and lovastatin

Valproate ____ ____ of lamotrigine. When initiating lamotrigine use the starter kit with ___ ___

reduces metabolism (increase risk for SJS/TENS) ; lower dose

Many ASM and ____ are metabolized by CYP enzymes. Inducers such as ____ will reduce levels. (IT is an autoinducer)

contraceptives ; carbamazepine

QT prolongation

Antiarrhythmics

Anti-infectives: FMT, ___ (except ___), antimalarials (_____)

Anti-depressants: ____, _____, _____, mirtazapine, trazodone, venlafaxine

Anti-emetics: ___, ____, promethazine

To avoid QT prolongation (especially in the elderly) do not exceed citalopram doses of ___ (or ____ if >65). Do not exceed escitalopram doses of ___ (or ____ if >65). Do not use ____ inpatient.

40 mg (20 mg) ; 20 mg (10 mg) ; droperidol

CNS depression: Several ER formulations act like short-acting ones when taken with ____. This increases rate of mortality.

alcohol

Cisplatin is basically GUARANTEED kidney damage. If available use ___to protect kidneys.

amifostine

PDE-5s + NITRATES: _____

PDE-5s + CYPCA4 inhibitor: ____ staring dose

PDE-5s + Alpha-1 blocker: start with ____ ____ aka _____ _____.

contraindicated

half

low dose ; half starting-dose