QT Prolonging Drugs: Gilenya has not been studied in patients treated with drugs that prolong the QT interval. Drugs that prolong the QT interval have been associated with cases of torsades de pointes in patients with bradycardia. Since initiation of Gilenya treatment results in decreased heart rate and may prolong the QT interval, patients on QT prolonging drugs with a known risk of torsades de pointes (e.g., citalopram, chlorpromazine, haloperidol, methadone, erythromycin) should be monitored overnight with continuous ECG in a medical facility (see DOSAGE & ADMINISTRATION and PRECAUTIONS).
Ketoconazole: The blood levels of fingolimod and fingolimod-phosphate are increased by 1.7-fold when used concomitantly with ketoconazole. Patients who use Gilenya and systemic ketoconazole concomitantly should be closely monitored, as the risk of adverse reactions is greater.
Vaccines: Gilenya reduces the immune response to vaccination. Vaccination may be less effective during and for up to 2 months after discontinuation of treatment with Gilenya (see Pharmacology under ACTIONS). Avoid the use of live attenuated vaccines during and for 2 months after treatment with Gilenya because of the risk of infection. It is recommended that pediatric patients, if possible, be brought up to date with all immunizations in agreement with current immunization guidelines prior to initiating Gilenya therapy.
Antineoplastic, Immunosuppressive, or Immune-Modulating Therapies: Antineoplastic, immune-modulating or immunosuppressive therapies, (including corticosteroids) are expected to increase the risk of immunosuppression, and the risk of additive immune system effects must be considered if these therapies are coadministered with Gilenya. When switching from drugs with prolonged immune effects, such as natalizumab, teriflunomide or mitoxantrone, the duration and mode of action of these drugs must be considered to avoid unintended additive immunosuppressive effects when initiating Gilenya (see PRECAUTIONS).
Drugs That Slow Heart Rate or Atrioventricular Conduction (e.g., beta blockers or diltiazem): Experience with Gilenya in patients receiving concurrent therapy with drugs that slow the heart rate or AV conduction (e.g., beta blockers, digoxin, or heart-rate slowing calcium channel blockers such as diltiazem or verapamil) is limited. Because initiation of Gilenya treatment may result in an additional decrease in heart rate, concomitant use of these drugs during Gilenya initiation may be associated with severe bradycardia or heart block. Seek advice from the physician prescribing these drugs regarding the possibility to switch to drugs that do not slow the heart rate or atrioventricular conduction before initiating Gilenya. Patients who cannot switch, should have overnight continuous ECG monitoring after the first dose (see DOSAGE & ADMINISTRATION and PRECAUTIONS).
Laboratory Test Interaction: Because Gilenya reduces blood lymphocyte counts via redistribution in secondary lymphoid organs, peripheral blood lymphocyte counts cannot be utilized to evaluate the lymphocyte subset status of a patient treated with Gilenya. A recent CBC should be available before initiating treatment with Gilenya.