Drug Interaction Report

MONITOR: Coadministration of Janus kinase (JAK) inhibitors with corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and/or opioids may increase the risk of gastrointestinal (GI) perforation. Patients with a prior history of peptic ulceration or diverticular disease may also have an increased risk. Adverse events of diverticulitis and GI perforation have been infrequently reported in clinical studies and postmarketing use of JAK inhibitors such as baricitinib, ruxolitinib, tofacitinib, and upadacitinib. However, the role of JAK inhibition in these events has not been determined. In studies with rheumatoid arthritis and ulcerative colitis patients, many were receiving background therapy with NSAIDs or corticosteroids.

MANAGEMENT: Caution is recommended when using JAK inhibitors in patients with a history of peptic ulceration or diverticular disease and in patients receiving concomitant treatment with drugs associated with an increased risk of GI perforation such as corticosteroids, NSAIDs, and opioids. Patients should be advised to contact their healthcare provider if they experience signs and symptoms of GI perforation such as severe abdominal pain, fever, chills, nausea, or vomiting.

ADJUST DOSE: Coadministration with one or more medications that may result in both moderate inhibition of CYP450 3A4 and potent inhibition of CYP450 2C19 may significantly increase the plasma concentrations of tofacitinib, which is primarily metabolized by the former isoenzyme with minor contribution from the latter. In study subjects, administration with the moderate CYP450 3A4 and potent CYP450 2C19 inhibitor fluconazole increased tofacitinib peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 27% and 79%, respectively, compared to administration of tofacitinib alone. Side effects including lymphopenia, neutropenia, anemia, serious infections, and hyperlipidemia may be increased.

MANAGEMENT: The dosage of tofacitinib should be reduced by 50% when used concomitantly with one or more medications that may result in both moderate inhibition of CYP450 3A4 and potent inhibition of CYP450 2C19. For example, the dose for patients receiving 10 mg twice daily should be reduced to 5 mg twice daily and the dose for patients receiving 5 mg twice daily should be reduced to 5 mg once daily. For patients receiving 11 mg once daily of the extended-release formulation, the dose should be reduced to 5 mg once daily of the immediate-release formulation. The dose for patients receiving 3.2 mg twice daily should be reduced to 3.2 mg once daily and the dose for patients receiving 4 mg twice daily should be reduced to 4 mg once daily. Moderate inhibitors of CYP450 3A4 include amiodarone, aprepitant, ciprofloxacin, crizotinib, darunavir, dalfopristin-quinupristin, diltiazem, dronedarone, erythromycin, fluconazole, fusidic acid, grapefruit juice, imatinib, isavuconazonium, netupitant, and verapamil. Potent inhibitors of CYP450 2C19 include fluconazole, fluvoxamine, esomeprazole, lansoprazole, and omeprazole. Inhibitors of CYP450 2C19 alone are unlikely to substantially alter the pharmacokinetics of tofacitinib.

Coadministration with proton pump inhibitors may decrease the oral bioavailability of aspirin and other salicylates. The interaction has been studied with omeprazole and aspirin, although data are conflicting. In one study, pretreatment with omeprazole (20 mg/day for 2 days) in 11 healthy volunteers led to a significant and progressively greater reduction in the mean serum salicylate level at 30, 60, and 90 minutes after administration of aspirin (650 mg single dose). The investigators suggest that acid suppression may reduce the lipophilic nature of aspirin, thereby adversely affecting its absorption from the gastrointestinal tract. Another study found no effect of omeprazole pretreatment (20 mg/day for 4 days) on plasma salicylate and aspirin levels, skin bleeding times, or antiplatelet effect of low-dose aspirin (125 mg single dose) in 14 healthy volunteers. However, these results do not exclude the possibility that omeprazole might interfere with the analgesic, antipyretic, or anti-inflammatory effects of aspirin, which has been demonstrated in rats.

Proton pump inhibitors may enhance the release rate of salicylates from enteric-coated formulations due to premature disruption of the coating and intragastric release of the drug secondary to an increase in gastric pH. In eight healthy volunteers, omeprazole pretreatment (20 mg/day for 4 days) did not affect the bioavailability of salicylate from uncoated aspirin tablets but significantly increased the absorption rate of salicylate from enteric-coated sodium salicylate tablets. The clinical significance of this interaction is unknown. Theoretically, it may increase the risk of gastric adverse effects associated with salicylates.

MONITOR: Grapefruit juice may increase the plasma concentrations of tofacitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. The extent and clinical significance are unknown. Moreover, pharmacokinetic alterations associated with interactions involving grapefruit juice are often subject to a high degree of interpatient variability.

MANAGEMENT: Until more information is available, some authorities recommend avoiding consumption of grapefruit juice during tofacitinib therapy (Canada). Patients receiving tofacitinib therapy who ingest grapefruits or grapefruit juice should be monitored for adverse effects and undue fluctuations in plasma drug levels.

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.

One study has reported that coadministration of caffeine and aspirin lead to a 25% increase in the rate of appearance and 17% increase in maximum concentration of salicylate in the plasma. A significantly higher area under the plasma concentration time curve of salicylate was also reported when both drugs were administered together. The exact mechanism of this interaction has not been specified. Physicians and patients should be aware that coadministration of aspirin and caffeine may lead to higher salicylate levels faster.