synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.pretomanidSerious - Use Alternative (1)butabarbital will decrease the level or effect of pretomanid by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Pretomanid is a CYP3A4 substrate. Avoid coadministration of strong or moderate CYP3A4 inducers.primidoneMonitor Closely (1)butabarbital and primidone both increase sedation. Use Caution/Monitor.procarbazineMinor (1)procarbazine increases levels of butabarbital by decreasing metabolism. Minor/Significance Unknown. Theoretical interaction.prochlorperazineMonitor Closely (1)butabarbital and prochlorperazine both increase sedation. Use Caution/Monitor.promethazineMonitor Closely (1)promethazine and butabarbital both increase sedation. Use Caution/Monitor.propafenoneMonitor Closely (1)butabarbital decreases levels of propafenone by increasing metabolism. Use Caution/Monitor.Minor (1)butabarbital will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.propofolMonitor Closely (1)propofol and butabarbital both increase sedation. Use Caution/Monitor.propranololMonitor Closely (1)butabarbital decreases levels of propranolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butabarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.propylhexedrineMonitor Closely (1)butabarbital increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protamineSerious - Use Alternative (1)butabarbital decreases effects of protamine by increasing metabolism. Avoid or Use Alternate Drug.protriptylineMonitor Closely (1)butabarbital and protriptyline both increase sedation. Use Caution/Monitor.Minor (1)butabarbital, protriptyline. Other (see comment). Minor/Significance Unknown. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.quazepamMonitor Closely (1)butabarbital and quazepam both increase sedation. Use Caution/Monitor.quetiapineMonitor Closely (2)butabarbital will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. butabarbital and quetiapine both increase sedation. Use Caution/Monitor.quinidineMonitor Closely (1)butabarbital will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.quinineMinor (1)butabarbital will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.rabeprazoleMinor (2)butabarbital will decrease the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown. butabarbital will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ramelteonMonitor Closely (2)butabarbital will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. butabarbital and ramelteon both increase sedation. Use Caution/Monitor.Minor (2)butabarbital will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown. butabarbital will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.ranolazineSerious - Use Alternative (1)butabarbital will decrease the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.remimazolamMonitor Closely (1)remimazolam, butabarbital. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.repaglinideMonitor Closely (1)butabarbital will decrease the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifampinMonitor Closely (1)rifampin decreases levels of butabarbital by increasing metabolism. Use Caution/Monitor.riluzoleMinor (1)butabarbital will decrease the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.rimegepantSerious - Use Alternative (1)butabarbital will decrease the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.risperidoneMonitor Closely (1)butabarbital and risperidone both increase sedation. Use Caution/Monitor.ritonavirMonitor Closely (1)butabarbital will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.romidepsinSerious - Use Alternative (1)butabarbital will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rose hipsMinor (1)butabarbital decreases levels of rose hips by increasing elimination. Minor/Significance Unknown.sageMinor (1)butabarbital and sage both increase sedation. Minor/Significance Unknown.salmeterolMonitor Closely (1)butabarbital increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.saquinavirMonitor Closely (1)butabarbital will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.saxagliptinMinor (1)butabarbital will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.scullcapMonitor Closely (1)butabarbital and scullcap both increase sedation. Use Caution/Monitor.secobarbitalMonitor Closely (1)butabarbital and secobarbital both increase sedation. Use Caution/Monitor.selegiline transdermalMinor (1)selegiline transdermal increases levels of butabarbital by decreasing metabolism. Minor/Significance Unknown. Theoretical interaction.selinexorSerious - Use Alternative (1)selinexor, butabarbital. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.selumetinibSerious - Use Alternative (1)butabarbital will decrease the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.shepherd's purseMonitor Closely (1)butabarbital and shepherd's purse both increase sedation. Use Caution/Monitor.Siberian ginsengMinor (1)Siberian ginseng increases effects of butabarbital by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.sildenafilMonitor Closely (1)butabarbital will decrease the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.silodosinSerious - Use Alternative (1)butabarbital will decrease the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.simvastatinSerious - Use Alternative (1)butabarbital will decrease the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.siponimodSerious - Use Alternative (1)butabarbital will decrease the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a drug that causes moderate CYP2C9 plus a moderate or strong CYP3A4 inducer is not recommended. Coadministration with moderate or strong CYP3A4 inducers alone is not recommended for patients with CYP2C9*1/*3 and*2/*3 genotype.sirolimusSerious - Use Alternative (1)butabarbital will decrease the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.sodium oxybateContraindicated (1)butabarbital, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Contraindicated. Coadministration with alcohol or sedative hypnotics are contraindicated because of additive CNS depression.solifenacinMonitor Closely (1)butabarbital will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.sorafenibMonitor Closely (1)butabarbital decreases levels of sorafenib by increasing metabolism. Use Caution/Monitor.sotalolMonitor Closely (1)butabarbital decreases levels of sotalol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butabarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.sotorasibSerious - Use Alternative (1)butabarbital will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.stiripentolSerious - Use Alternative (2)butabarbital will decrease the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP3A4 inducers, increase stiripentol dose. stiripentol, butabarbital. Either increases effects of the other by sedation. Avoid or Use Alternate Drug. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.sufentanilMonitor Closely (1)butabarbital and sufentanil both increase sedation. Use Caution/Monitor.Minor (1)butabarbital will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.sufentanil SLMonitor Closely (1)butabarbital decreases effects of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of CYP3A4 inducers may decrease sufentanil levels and efficacy, possibly precipitating withdrawal syndrome in patients who have developed physical dependence to sufentanil. Discontinuation of concomitantly used CYP3A4 inducers may increase sufentanil plasma concentration.Serious - Use Alternative (1)sufentanil SL, butabarbital. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.sulfamethoxazoleMinor (1)butabarbital will decrease the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.sunitinibMonitor Closely (1)butabarbital will decrease the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tacrolimusMonitor Closely (1)butabarbital will decrease the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tadalafilMonitor Closely (1)butabarbital will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.tamoxifenMonitor Closely (2)butabarbital will decrease the level or effect of tamoxifen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. butabarbital will decrease the level or effect of tamoxifen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tapentadolMonitor Closely (1)butabarbital and tapentadol both increase sedation. Use Caution/Monitor.tazemetostatSerious - Use Alternative (1)butabarbital will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.temazepamMonitor Closely (1)butabarbital and temazepam both increase sedation. Use Caution/Monitor.temsirolimusMonitor Closely (1)butabarbital will decrease the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.terbinafineMonitor Closely (1)butabarbital will decrease the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.terbutalineMonitor Closely (1)butabarbital increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.tezacaftorSerious - Use Alternative (1)butabarbital will decrease the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.thalidomideMonitor Closely (1)thalidomide increases effects of butabarbital by unspecified interaction mechanism. Use Caution/Monitor. Increased sedative effects.theophyllineMonitor Closely (2)butabarbital will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. butabarbital will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.thioridazineMonitor Closely (1)butabarbital and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases levels of butabarbital by unspecified interaction mechanism. Minor/Significance Unknown.thiothixeneMonitor Closely (1)butabarbital and thiothixene both increase sedation. Use Caution/Monitor.thyroid desiccatedMinor (1)butabarbital decreases levels of thyroid desiccated by increasing metabolism. Minor/Significance Unknown.tiboloneMinor (1)butabarbital decreases levels of tibolone by increasing metabolism. Minor/Significance Unknown. Theoretical interaction.timololMonitor Closely (1)butabarbital decreases levels of timolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butabarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.tinidazoleMonitor Closely (1)butabarbital will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tipranavirMonitor Closely (1)butabarbital will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tivozanibSerious - Use Alternative (1)butabarbital will decrease the level or effect of tivozanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.tizanidineSerious - Use Alternative (1)butabarbital will decrease the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.tolbutamideMinor (1)butabarbital will decrease the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.tolterodineMonitor Closely (1)butabarbital will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tolvaptanSerious - Use Alternative (1)butabarbital will decrease the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.topiramateMonitor Closely (1)butabarbital and topiramate both increase sedation. Modify Therapy/Monitor Closely.Minor (1)butabarbital decreases levels of topiramate by increasing metabolism. Minor/Significance Unknown.tramadolMonitor Closely (1)butabarbital and tramadol both increase sedation. Use Caution/Monitor.tranylcypromineMinor (1)tranylcypromine increases levels of butabarbital by decreasing metabolism. Minor/Significance Unknown. Theoretical interaction.trazodoneMonitor Closely (2)butabarbital will decrease the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. butabarbital and trazodone both increase sedation. Use Caution/Monitor.Minor (1)butabarbital, trazodone. Other (see comment). Minor/Significance Unknown. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.triamcinolone acetonide injectable suspensionMonitor Closely (1)butabarbital will decrease the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.triazolamMonitor Closely (2)butabarbital will decrease the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. butabarbital and triazolam both increase sedation. Use Caution/Monitor.triclofosMonitor Closely (1)butabarbital and triclofos both increase sedation. Use Caution/Monitor.trifluoperazineMonitor Closely (1)butabarbital and trifluoperazine both increase sedation. Use Caution/Monitor.trimipramineMonitor Closely (1)butabarbital and trimipramine both increase sedation. Use Caution/Monitor.Minor (1)butabarbital, trimipramine. Other (see comment). Minor/Significance Unknown. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.triprolidineMonitor Closely (1)triprolidine and butabarbital both increase sedation. Use Caution/Monitor.tucatinibSerious - Use Alternative (1)butabarbital will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.ubrogepantSerious - Use Alternative (1)butabarbital will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.upadacitinibSerious