imatinib mesylate

Significantly increased plasma concentrations of imatinib, leading to increased risk of imatinib-related adverse effects (e.g., myelosuppression, fluid retention, hepatotoxicity).

Avoid concomitant use. If co-administration is unavoidable, consider a significant dose reduction of imatinib (e.g., by 25-50%) and close monitoring for adverse effects. Alternatively, use a less potent CYP3A4 inhibitor.

Significantly decreased plasma concentrations of imatinib, potentially leading to loss of efficacy and treatment failure.

Avoid concomitant use. If co-administration is unavoidable, consider a significant dose increase of imatinib (e.g., by 50-100%) and close monitoring for loss of efficacy. Alternatively, use a non-CYP3A4 inducing antitubercular drug.

Decreased plasma concentrations of imatinib, potentially leading to reduced efficacy.

Avoid concomitant use if possible. If unavoidable, monitor imatinib efficacy closely and consider increasing imatinib dose. Consider alternative anticonvulsants.

Increased plasma concentrations of imatinib, leading to increased risk of imatinib-related adverse effects.

Avoid concomitant use if possible. If unavoidable, consider a temporary dose reduction of imatinib (e.g., by 25-50%) and close monitoring for adverse effects. Alternatively, use an antibiotic that is not a strong CYP3A4 inhibitor.

Increased plasma concentrations of cyclosporine, leading to increased risk of cyclosporine-related toxicity (e.g., nephrotoxicity, neurotoxicity).

Monitor cyclosporine trough levels closely when initiating or discontinuing imatinib or changing its dose. Adjust cyclosporine dose as needed to maintain therapeutic levels and minimize toxicity.

Decreased plasma concentrations of imatinib, potentially leading to reduced efficacy.

Monitor for reduced efficacy of imatinib. Consider increasing the imatinib dose if clinically indicated, especially with long-term dexamethasone use. Monitor for imatinib adverse effects if dexamethasone is discontinued.

Increased plasma concentrations of imatinib, potentially leading to increased risk of imatinib-related adverse effects.

Advise patients to avoid consuming grapefruit or grapefruit juice while on imatinib therapy.

Increased plasma concentrations of midazolam, leading to enhanced and prolonged sedative effects.

Exercise caution. Consider reducing the dose of midazolam or using an alternative benzodiazepine not metabolized by CYP3A4 if co-administration is necessary. Monitor for increased sedation.

Decreased plasma concentrations of imatinib, potentially leading to reduced efficacy. Also, imatinib may inhibit phenytoin metabolism, potentially increasing phenytoin levels.

Avoid concomitant use if possible. If unavoidable, monitor imatinib efficacy and phenytoin levels closely. Adjust doses of both drugs as needed. Consider alternative anticonvulsants.

Increased plasma concentrations of simvastatin, leading to an increased risk of statin-related adverse effects, particularly myopathy and rhabdomyolysis.

Avoid concomitant use. If co-administration is necessary, consider using a statin that is not primarily metabolized by CYP3A4 (e.g., pravastatin, rosuvastatin) or significantly reduce the simvastatin dose and monitor for muscle-related symptoms.

Increased plasma concentrations of tacrolimus, leading to increased risk of tacrolimus-related toxicity (e.g., nephrotoxicity, neurotoxicity).

Monitor tacrolimus trough levels closely when initiating or discontinuing imatinib or changing its dose. Adjust tacrolimus dose as needed to maintain therapeutic levels and minimize toxicity.

Increased anticoagulant effect of warfarin, leading to an increased risk of bleeding.

Monitor INR closely (e.g., weekly or more frequently) when initiating or discontinuing imatinib or changing its dose. Adjust warfarin dose as needed to maintain target INR.