Interactions / P450 Flashcards
If Colchicine was given with a P450 Inhibitor (Clarithromycin, Intraconazole) what would happen to the plasma levels of colchicine?
Increased plasma levels of Colchicine (leading to toxicity)
If allopurinol was given with an immunosuppressant like azathioprine……
What may occur?
Reduce the efficacy of Allopurinol
Should Allopurinol be given with Warfarin?
No
If Allopurinol is given with Theophylline…..
What may occur?
Increased Theopylline levels
Probenecid ______ (increases/decreases) PCN secretion
Decreases Secretion of PCN which in turn increases PCN levels
Lesinurad is a weak inducer of what P450 isoenzyme?
3A4
Why should vitamin D be avoided in patients on corticosteroids?
Corticosteroids impair Vitamin D metabolism
Can patients on Vitamin D take Orlistat?
No, Orlistat decreases the metabolism of fat-soluble vitamins
Should patients on Phenobarbital or Phenytoin take Vitamin D?
No, because those medications increase Vitamin D metabolism to their inactive compounds
What drugs will Atomoxetine interact with?
2D6 Inhibitors
MAOIs
Albuterol
Zolpidem (Ambien) will interact with medications that a substrates of what P450 isoenzyme?
CYP 3A4 Substrates
Should Eszopiclone (Lunesta) be used in combination with EtOH and CNS Depressants?
No
Why should anticoagulants be avoided with mealtonin?
Melatonin potentiates anticoagulation
Why should patients taking AEDs avoided Melatonin?
Melatonin inhibits the effects of AEDs
Would you expect to see an increased or decreased efficacy of Anti-hypertensives if taken with melatonin?
Increased Efficacy
So you would see a LOWER BP
Why should diabetics avoid melatonin?
Leads to increased glucose levels
Tasimelteon should be avoided with strong CYP 1A2 __________ (inhibitor/Inducer)
Tasimelteon should be avoided with strong CYP 3A4 __________ (inhibitor/Inducer)
1A2 Inhibitors
3A4 Inducers
Should Tasimelteon be used in pregnancy?
No, potential for fetal harm
Which SSRIs are 2D6 Inhibitors?
Fluoxetine
Paroxetine
Sertraline
Which SSRIs are 2C9 Inhibitors?
Paroxetine
Sertraline
Which TWO SSRIs have the fewest drug interactions?
Citalopram
Escitalopram
Levomilnacirpan is a strong 3A4 ________ (inhibitor/Inducer)
Inhibitor
Which SNRIs are 2D6 Inhibitors?
Vortioxetine
Duloxetine
Should SNRIs be used with platelet inhibitors?
No
If Venlafaxine (Effexor) is used in combination with SSRIs, NSAIDs, ASA, or Warfarin……
What is the patient at an increased risk for?
Bleeding
Should Duloxetine (Cymbalta) be used with MAOIs?
No
T/F: Milnacipran has NO P450 interactions
True
Should TCAs be used with Anticholinergic medications?
No (Increased Anticholinergic Effect)
TCAs are CYP 2D6 _______ (inducers/Substrates/Inhibitors)
Substrates
So avoid in poor metabolizers or SSRIs which are inhibitors
St. John’s Wort is a potent P450 ________
Inducer
You should _______ (increase/decrease) the dose of Clozapine when used in combination with Ciprofloxacin
Decrease the Dose of Clozapine with P450 1A2 inhibitors like ciprofloxacin
(Avoid this medication in strong P450 Inhibitors)
