Tegretol is a potent inducer of hepatic 3A4 and is also known to be an inducer of CYP1A2, 2B6, 2C9/19 and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP 1A2, 2B6, 2C9/19 and 3A4, through induction of their metabolism. When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
- When Galepsin is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If Galepsin is later withdrawn, the aripiprazole dose should be reduced.
- When Galepsin is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
- The use of concomitant strong CYP3A4 inducers such as Galepsin should be avoided with temsirolimus. If patients must be coadministered Galepsin with temsirolimus, an adjustment of temsirolimus dosage should be considered.
- The use of Galepsin with lapatinib should generally be avoided. If Galepsin is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If Galepsin is discontinued, the lapatinib dose should be reduced.
- Concomitant use of Galepsin with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of Galepsin with nefazodone is contraindicated (see CONTRAINDICATIONS).
- Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
Taking certain heart drugs with Galepsin will increase the level of Galepsin in your body. This can cause side effects. Your doctor may monitor your blood levels of Galepsin if you’re taking it with one of these drugs:
Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING and SPECIAL PRECAUTION sections, call your doctor immediately:
- fast, slow, or pounding heartbeat
- yellowing of the skin or eyes
- dark urine
- pain on the right side of your stomach area
- loss of appetite
- vision changes
- swelling of your face, eyes, eyelids, lips, or tongue
- difficulty swallowing or breathing
- headache, new or increased number of seizures, difficulty concentrating, confusion, weakness, or unsteadiness
- severe rash with one or more of the following: fever, muscle or joint aches, red or swollen eyes, blisters or peeling skin, mouth sores, or swelling of your face or neck
Galepsin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
Taking certain cancer drugs with Galepsin will decrease the level of Galepsin in your body. This means it won’t work as well to treat your condition. Your doctor may monitor your blood levels of Galepsin if you’re taking it with one of these drugs:
Taking other cancer drugs with Galepsin will change the level of the cancer drug in your body. Your doctor should avoid use of these drugs together. However, if they must be used together, you doctor may change the dosage of your cancer drug. Examples of these drugs include:
Taking cyclophosphamide with Galepsin will increase the level of the cancer drug in your body. Your doctor may change your dosage of the cancer drug if you take it with Galepsin.
See also How to Use section.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: certain azole antifungals (isavuconazonium, voriconazole), orlistat.
Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication.
Other medications can affect the removal of Galepsin from your body, which may affect how Galepsin works. Examples include macrolide antibiotics (such as erythromycin), rifamycins (such as rifabutin), St. John's wort, among others.
Galepsin can speed up the removal of other drugs from your body, which may affect how they work. Examples of affected drugs include artemether/lumefantrine, boceprevir, certain drugs used to prevent blood clots (anticoagulants such as apixaban, rivaroxaban), certain calcium channel blockers (such as nifedipine, nimodipine), nefazodone, HIV NNRTIs (such as delavirdine, efavirenz, etravirine, rilpivirine), praziquantel, ranolazine, among others.
This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while taking this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.
Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), and narcotic pain relievers (such as codeine, hydrocodone).
Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
This medication may interfere with certain lab tests (such as thyroid function, some pregnancy tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.