Unknown. lansoprazole increases toxicity of theophylline by Other (see comment). Minor/Significance Unknown. Comment: Prolonged use of proton pump inhibitors can cause hypochlorhydria, which in turn causes peristalsis in small intestine to increase and peristalsis in the proximal colon to decrease; monitor for toxicity.lapatinibMonitor Closely (1)lapatinib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.larotrectinibMinor (1)larotrectinib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lenacapavirMonitor Closely (1)lenacapavir will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.leniolisibSerious - Use Alternative (1)leniolisib will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid leniolisib with CYP1A2 substrates that have a narrow therapeutic indexlevocetirizineMinor (1)theophylline increases levels of levocetirizine by decreasing elimination. Minor/Significance Unknown.levoketoconazoleSerious - Use Alternative (1)levoketoconazole will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.levonorgestrel oral/ethinylestradiol/ferrous bisglycinateMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will increase the level or effect of theophylline by decreasing metabolism. Use Caution/Monitor. Combined oral contraceptives containing EE may inhibit the metabolism and increase plasma concentrations of cyclosporine.levothyroxineMinor (1)levothyroxine decreases levels of theophylline by increasing elimination. Minor/Significance Unknown.liothyronineMinor (1)liothyronine decreases levels of theophylline by increasing elimination. Minor/Significance Unknown.lithiumMinor (1)theophylline decreases levels of lithium by increasing renal clearance. Minor/Significance Unknown.lonafarnibSerious - Use Alternative (1)lonafarnib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.lonapegsomatropinMonitor Closely (2)lonapegsomatropin will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrates lonapegsomatropin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limited published data indicate that growth hormone treatment increases cytochrome P450 (CYP450)-mediated antipyrine clearance. Caution with sensitive CYP substrateslumefantrineMonitor Closely (1)lumefantrine will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.marijuanaMonitor Closely (1)marijuana will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.methimazoleMonitor Closely (1)methimazole increases levels of theophylline by decreasing elimination. Use Caution/Monitor.methotrexateMonitor Closely (1)methotrexate increases levels of theophylline by unknown mechanism. Use Caution/Monitor. Methotrexate may decrease the clearance of theophylline. Theophylline levels should be monitored when used concomitantly with methotrexate.methylprednisoloneMonitor Closely (1)methylprednisolone will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.metoclopramide intranasalSerious - Use Alternative (1)theophylline, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.metoprololMonitor Closely (1)metoprolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.metronidazoleMonitor Closely (1)metronidazole will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.mexiletineMonitor Closely (1)mexiletine will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.miconazole vaginalMonitor Closely (1)miconazole vaginal will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.midazolam intranasalMonitor Closely (1)midazolam intranasal, theophylline. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.mitotaneMonitor Closely (1)mitotane decreases levels of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.modafinilMonitor Closely (1)modafinil will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.nadololMonitor Closely (1)nadolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.nebivololMonitor Closely (1)nebivolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.nefazodoneSerious - Use Alternative (1)nefazodone will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.nelfinavirMonitor Closely (1)nelfinavir will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nevirapineMonitor Closely (1)nevirapine will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nifedipineMonitor Closely (1)nifedipine will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nilotinibMonitor Closely (1)nilotinib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nilutamideMonitor Closely (1)nilutamide will increase the level or effect of theophylline by decreasing metabolism. Use Caution/Monitor.obeticholic acidMonitor Closely (1)obeticholic acid will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. CYP1A2 substrates that have a narrow therapeutic index should be monitored closely and the dose adjusted accordingly.olodaterol inhaledMonitor Closely (1)theophylline and olodaterol inhaled both decrease serum potassium. Use Caution/Monitor.olopatadine intranasalSerious - Use Alternative (1)theophylline and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. omaveloxoloneMonitor Closely (1)omaveloxolone will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Omaveloxolone may reduce systemic exposure of sensitive CYP3A4 substrates. Check prescribing information of substrate if dosage modification is needed. omeprazoleMinor (2)omeprazole will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown. omeprazole increases toxicity of theophylline by Other (see comment). Minor/Significance Unknown. Comment: Prolonged use of proton pump inhibitors can cause hypochlorhydria, which in turn causes peristalsis in small intestine to increase and peristalsis in the proximal colon to decrease; monitor for toxicity.osilodrostatMonitor Closely (1)osilodrostat will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.oxcarbazepineMonitor Closely (1)oxcarbazepine will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.pacritinibSerious - Use Alternative (1)pacritinib will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.pantoprazoleMonitor Closely (1)pantoprazole increases toxicity of theophylline by Other (see comment). Use Caution/Monitor. Comment: Prolonged use of proton pump inhibitors can cause hypochlorhydria, which in turn causes peristalsis in small intestine to increase and peristalsis in the proximal colon to decrease; monitor for toxicity.pefloxacinSerious - Use Alternative (1)pefloxacin will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.peginterferon alfa 2aMonitor Closely (1)peginterferon alfa 2a will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.peginterferon alfa 2bMonitor Closely (1)peginterferon alfa 2b increases levels of theophylline by unknown mechanism. Use Caution/Monitor. Alpha interferons may decrease the clearance of theophylline resulting in increased plasma concentrations.penbutololMonitor Closely (1)penbutolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.pentobarbitalMonitor Closely (2)pentobarbital will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. pentobarbital will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.pentoxifyllineMinor (1)pentoxifylline increases levels of theophylline by decreasing metabolism. Minor/Significance Unknown.phenobarbitalMonitor Closely (2)phenobarbital will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. phenobarbital will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.phenytoinMonitor Closely (1)phenytoin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.phytoestrogensMinor (2)phytoestrogens increases levels of theophylline by decreasing metabolism. Minor/Significance Unknown. phytoestrogens increases levels of theophylline by decreasing elimination. Minor/Significance Unknown.pindololMonitor Closely (1)pindolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.pipemidic acidMonitor Closely (1)pipemidic acid will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.posaconazoleMonitor Closely (1)posaconazole will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prednisoneMonitor Closely (1)prednisone will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.primidoneMonitor Closely (2)primidone will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. primidone will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.propafenoneMinor (1)propafenone increases levels of theophylline by decreasing renal clearance. Minor/Significance Unknown.propranololMonitor Closely (1)propranolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.propylthiouracilMonitor Closely (1)propylthiouracil increases levels of theophylline by decreasing elimination. Use Caution/Monitor.pyrantel pamoateMinor (1)pyrantel pamoate increases levels of theophylline by unspecified interaction mechanism. Minor/Significance Unknown.pyridoxineMinor (1)theophylline decreases levels of pyridoxine by altering metabolism. Minor/Significance Unknown.pyridoxine (Antidote)Minor (1)theophylline decreases levels of pyridoxine (Antidote) by altering metabolism. Minor/Significance Unknown.quinupristin/dalfopristinMonitor Closely (1)quinupristin/dalfopristin will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rabeprazoleMonitor Closely (1)rabeprazole increases toxicity of theophylline by Other (see comment). Use Caution/Monitor. Comment: Prolonged use of proton pump inhibitors can cause hypochlorhydria, which in turn causes peristalsis in small intestine to increase and peristalsis in the proximal colon to decrease; monitor for toxicity.regadenosonSerious - Use Alternative (1)theophylline decreases effects of regadenoson by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid methylxanthines for 12 hours before regadenoson administration.ribociclibMinor (1)ribociclib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.rifabutinSerious - Use Alternative (1)rifabutin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifampinMonitor Closely (1)rifampin will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifapentineMonitor Closely (1)rifapentine will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.riociguatContraindicated (1)theophylline, riociguat. Either increases effects of the other by additive vasodilation. Contraindicated. Coadministration of nonspecific PDE-5 inhibitors (eg, dipyridamole, theophylline) and guanylate cyclase stimulators (eg, riociguat) is contraindicated due to risk of additive hypotension.ritlecitinibMonitor Closely (2)ritlecitinib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Ritlecitinib inhibits CYP3A4 substrates; coadministration increases AUC and peak plasma concentration sensitive substrates, which may increase risk of adverse reactions. Additional monitoring and dosage adjustment may be needed in accordance with product labeling of CYP3A substrates. ritlecitinib will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Ritlecitinib inhibits CYP1A2 substrates; coadministration increases AUC and peak plasma concentration sensitive substrates, which may increase risk of adverse reactions. Additional monitoring and dosage adjustment may be needed in accordance with product labeling of CYP1A2 substrates. ritonavirMonitor Closely (1)ritonavir will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ropeginterferon alfa 2bSerious - Use Alternative (1)ropeginterferon alfa 2b and theophylline both increase Other (see comment). Avoid or Use Alternate Drug. Narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity.rucaparibSerious - Use Alternative (1)rucaparib will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rufinamideMonitor Closely (1)rufinamide will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.sarilumabMonitor Closely (1)sarilumab, theophylline. Other (see comment). Use Caution/Monitor. Comment: Formation of