amphetamine is decreased compared to when administered alone; monitor patients for changes in clinical effect and adjust therapy based on clinical response.estazolamMonitor Closely (1)estazolam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ethanolMonitor Closely (1)ethanol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.etherSerious - Use Alternative (1)ether increases toxicity of methamphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.ethosuximideMinor (1)methamphetamine decreases levels of ethosuximide by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.eucalyptusMinor (1)eucalyptus increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.fedratinibMonitor Closely (1)fedratinib will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.fenfluramineMonitor Closely (2)methamphetamine and fenfluramine both decrease sedation. Use Caution/Monitor. fenfluramine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.fluoxetineSerious - Use Alternative (1)fluoxetine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.fluphenazineMonitor Closely (2)fluphenazine, methamphetamine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. fluphenazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.flurazepamMonitor Closely (1)flurazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.formoterolMonitor Closely (2)formoterol and methamphetamine both decrease sedation. Use Caution/Monitor. formoterol and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.givosiranSerious - Use Alternative (1)givosiran will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.green teaMonitor Closely (1)green tea, methamphetamine. Other (see comment). Use Caution/Monitor. Comment: Green tea may include caffeine. Caffeine is a CNS-stimulant and additive effects may be seen when coadministered with other CNS stimulants. Caffeine should be avoided or used cautiously.guaranaMinor (1)guarana increases effects of methamphetamine by pharmacodynamic synergism. Minor/Significance Unknown.haloperidolMonitor Closely (2)haloperidol will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. haloperidol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydralazineMonitor Closely (1)hydralazine, methamphetamine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.hydrocodoneMonitor Closely (1)hydrocodone, methamphetamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.hydromorphoneMonitor Closely (1)hydromorphone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydroxyzineMonitor Closely (1)hydroxyzine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.iloperidoneMonitor Closely (1)iloperidone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.imatinibMonitor Closely (1)imatinib will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.imipramineMonitor Closely (1)imipramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)imipramine, methamphetamine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.iobenguane I 123Contraindicated (1)methamphetamine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.iobenguane I 131Serious - Use Alternative (1)methamphetamine will decrease the level or effect of iobenguane I 131 by Other (see comment). Avoid or Use Alternate Drug. Based on the mechanism of action of iobenguane, drugs that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells, and thus, reduce iobenguane efficacy. Discontinue interfering drugs for at least 5 half-lives before administration of either the dosimetry or an iobenguane dose. Do not administer these drugs until at least 7 days after each iobenguane dose.ioflupane I 123Monitor Closely (1)methamphetamine decreases effects of ioflupane I 123 by receptor binding competition. Use Caution/Monitor. Drugs that bind to dopamine transporter receptor with high affinity may interfere with the image following ioflupane I 123 administration.isocarboxazidContraindicated (1)isocarboxazid increases effects of methamphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.isofluraneSerious - Use Alternative (1)isoflurane increases toxicity of methamphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.isoproterenolMonitor Closely (2)isoproterenol and methamphetamine both decrease sedation. Use Caution/Monitor. isoproterenol and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.ketotifen, ophthalmicMonitor Closely (1)ketotifen, ophthalmic increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lansoprazoleMinor (1)lansoprazole decreases levels of methamphetamine by Other (see comment). Minor/Significance Unknown. Comment: Time to maximum concentration (Tmax) of amphetamine is decreased compared to when administered alone; monitor patients for changes in clinical effect and adjust therapy based on clinical response.levalbuterolMonitor Closely (2)levalbuterol and methamphetamine both decrease sedation. Use Caution/Monitor. levalbuterol and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.levorphanolMonitor Closely (1)levorphanol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.linezolidContraindicated (1)linezolid increases effects of methamphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.lisdexamfetamineMonitor Closely (2)lisdexamfetamine and methamphetamine both decrease sedation. Use Caution/Monitor. lisdexamfetamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.lofepramineMonitor Closely (1)lofepramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)lofepramine, methamphetamine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.lofexidineMonitor Closely (1)lofexidine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.loprazolamMonitor Closely (1)loprazolam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lorazepamMonitor Closely (1)lorazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lorcaserinMonitor Closely (1)lorcaserin will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)methamphetamine and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.lormetazepamMonitor Closely (1)lormetazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.loxapineMonitor Closely (1)loxapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.loxapine inhaledMonitor Closely (1)loxapine inhaled increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lumefantrineSerious - Use Alternative (1)lumefantrine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.maprotilineMonitor Closely (1)maprotiline increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)maprotiline, methamphetamine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.maravirocMonitor Closely (1)maraviroc will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.marijuanaMonitor Closely (2)marijuana will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. marijuana increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.melatoninMonitor Closely (1)melatonin increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.meperidineMonitor Closely (1)meperidine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.meprobamateMonitor Closely (1)meprobamate increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaproterenolMonitor Closely (2)metaproterenol and methamphetamine both decrease sedation. Use Caution/Monitor. metaproterenol and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.metforminMonitor Closely (1)methamphetamine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.methadoneMonitor Closely (1)methadone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methoxyfluraneSerious - Use Alternative (1)methoxyflurane increases toxicity of methamphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.methyldopaMonitor Closely (1)methyldopa increases effects of methamphetamine by unknown mechanism. Use Caution/Monitor.methylenedioxymethamphetamineMonitor Closely (2)methamphetamine and methylenedioxymethamphetamine both decrease sedation. Use Caution/Monitor. methamphetamine and methylenedioxymethamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.methylergonovineSerious - Use Alternative (1)methylergonovine, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.methylphenidateMonitor Closely (1)methamphetamine increases effects of methylphenidate by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.midazolamMonitor Closely (1)midazolam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.midodrineMonitor Closely (2)methamphetamine and midodrine both decrease sedation. Use Caution/Monitor. methamphetamine and midodrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.mirabegronMonitor Closely (1)mirabegron will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineMonitor Closely (1)mirtazapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.modafinilMonitor Closely (1)methamphetamine and modafinil both decrease sedation. Use Caution/Monitor.morphineMonitor Closely (1)morphine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.motherwortMonitor Closely (1)motherwort increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.moxonidineMonitor Closely (1)moxonidine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.nabiloneMonitor Closely (1)nabilone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.nalbuphineMonitor Closely (1)nalbuphine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.nilotinibMonitor Closely (1)nilotinib will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.norepinephrineMonitor Closely (2)norepinephrine and methamphetamine both decrease sedation. Use Caution/Monitor. norepinephrine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.nortriptylineMonitor Closely (1)nortriptyline increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)nortriptyline, methamphetamine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.olanzapineMonitor Closely (1)olanzapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.omeprazoleMinor (1)omeprazole decreases levels of methamphetamine by Other (see comment). Minor/Significance Unknown. Comment: Time to maximum concentration (Tmax) of amphetamine is decreased compared to when administered alone; monitor patients for changes in clinical effect and adjust therapy based on clinical response.opium tinctureMonitor Closely (1)opium tincture increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.oxazepamMonitor Closely (1)oxazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.oxycodoneMonitor Closely (1)oxycodone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.oxymorphoneMonitor Closely (1)oxymorphone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.oxytocinMonitor Closely (1)oxytocin increases effects of methamphetamine by pharmacodynamic synergism. Use Caution/Monitor.ozanimodSerious - Use Alternative (1)ozanimod increases toxicity of methamphetamine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.paliperidoneMonitor Closely (1)paliperidone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.pantoprazoleMinor (1)pantoprazole decreases levels of methamphetamine by Other (see comment). Minor/Significance Unknown. Comment: Time to maximum concentration (Tmax) of amphetamine is decreased compared to when administered alone; monitor patients for changes in clinical effect and adjust therapy based on clinical response.papaveretumMonitor Closely (1)papaveretum increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.parecoxibMonitor Closely (1)parecoxib will increase the level or effect of methamphetamine by