Page 1182 - Basic _ Clinical Pharmacology ( PDFDrive )

1168 SECTION X Special Topics

TABLE 66–1 Important drug interactions.

Drug or Properties Promoting
Drug Group Drug Interaction Clinically Documented Interactions
Macrolides The macrolides clarithromycin Benzodiazepines: [P] Decreased metabolism of alprazolam, midazolam, triazolam.
and erythromycin are known to
inhibit CYP3A4 and P-glycoprotein. Eplerenone: [P] Decreased metabolism of eplerenone.
Azithromycin does not appear to Ergot alkaloids: [P] Decreased elimination of ergot alkaloids.
inhibit CYP3A4 but is a modest
inhibitor of P-glycoprotein. Kinase inhibitors: [P] Decreased metabolism of axitinib, bosutinib, ceritinib,
cabozantinib, cobimetinib, crizotinib, dabrafenib, dasatinib, erlotinib, gefitinib, ibrutinib,
idelalisib, imatinib, ixazomib, lapatinib, nilotinib, nintedanib, olaparib, osimertinib,
palbociclib, pazopanib, ponatinib, regorafenib, ruxolitinib, sunitinib, tofacitinib,
vandetanib, and vemurafenib by clarithromycin and erythromycin.
Opioid analgesics: [P] Decreased elimination of alfentanil, fentanyl, methadone,
oxycodone, and sufentanil.
Phosphodiesterase inhibitors: [P] Decreased metabolism of phosphodiesterase
inhibitor.
Pimozide: [P] Increased pimozide concentrations.
Quinidine: [P] Increased serum quinidine concentrations.
Theophylline: [P] Decreased metabolism of theophylline.
See also Anticoagulants, oral; Calcium channel blockers; Carbamazepine; Cisapride;
Colchicine; Cyclosporine; Digitalis glycosides; HMG-CoA reductase inhibitors.
Monoamine Increased norepinephrine stored in Anorexiants: [P] Hypertensive episodes due to release of stored norepinephrine
oxidase adrenergic neuron. Displacement (benzphetamine, diethylpropion, mazindol, phendimetrazine, phentermine).
inhibitors of these stores by other drugs
(MAOIs) may produce acute hypertensive Antidiabetic agents: [P] Additive hypoglycemic effect.
response. MAOIs have intrinsic Buspirone: [NE] Possible serotonin syndrome; avoid concurrent use.
hypoglycemic activity.
Dextromethorphan: [NP] Severe reactions (hyperpyrexia, coma, death) have been
reported.
Guanethidine: [P] Reversal of the hypotensive action of guanethidine.
Mirtazapine: [NE] Possible serotonin syndrome; avoid concurrent use.
Nefazodone: [NP] Possible serotonin syndrome; avoid concurrent use.
Opioid analgesics: [NP] Some patients develop hypertension, rigidity, excitation;
meperidine more likely to interact than morphine; avoid concurrent use.
Phenylephrine: [P] Hypertensive episode, since phenylephrine is metabolized by
monoamine oxidase.
Selective serotonin reuptake inhibitors (SSRIs): [P] Fatalities have occurred
due to serotonin syndrome; contraindicated in patients taking MAOIs; avoid
concurrent use.
Sibutramine: [NE] Possible serotonin syndrome; avoid concurrent use.
Sympathomimetics (indirect-acting): [HP] Hypertensive episode due to release of
stored norepinephrine (amphetamines, ephedrine, isometheptene, phenylpropanol-
amine, pseudoephedrine).
Tramadol: [NP] Possible serotonin syndrome; avoid concurrent use.
Venlafaxine: [NP] Possible serotonin syndrome; avoid concurrent use.
See also Antidepressants, tricyclic and heterocyclic; Levodopa.
E, Expected; HP, Highly predictable. Interaction occurs in almost all patients receiving the interacting combination; P, Predictable. Interaction occurs in most patients receiving the
combination; NP, Not predictable. Interaction occurs only in some patients receiving the combination; NE, Not established. Insufficient data available on which to base estimate
of predictability.
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