not clear, use caution. Use Caution/Monitor.armodafinilMonitor Closely (1)armodafinil and methamphetamine both decrease sedation. Use Caution/Monitor.artemether/lumefantrineSerious - Use Alternative (1)artemether/lumefantrine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.asenapineMonitor Closely (1)asenapine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.azelastineMonitor Closely (1)azelastine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.belladonna and opiumMonitor Closely (1)belladonna and opium increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benazeprilMonitor Closely (1)methamphetamine decreases effects of benazepril by pharmacodynamic antagonism. Use Caution/Monitor.benperidolMonitor Closely (1)benperidol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benzhydrocodone/acetaminophenMonitor Closely (1)benzhydrocodone/acetaminophen, 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.benzphetamineMonitor Closely (2)methamphetamine and benzphetamine both decrease sedation. Use Caution/Monitor. benzphetamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.bromocriptineMonitor Closely (1)bromocriptine, methamphetamine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Hypertension, V tach.brompheniramineMonitor Closely (1)brompheniramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine buccalMonitor Closely (1)buprenorphine buccal increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine subdermal implantMonitor Closely (1)methamphetamine, buprenorphine subdermal implant. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.buprenorphine, long-acting injectionMonitor Closely (1)methamphetamine, buprenorphine, long-acting injection. Either increases toxicity of the other by serotonin levels. Use Caution/Monitor. Concomitant use could result in life-threatening serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation, and during dose adjustment of the serotonergic drug. Discontinue buprenorphine if serotonin syndrome is suspected.bupropionMonitor Closely (2)bupropion will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. methamphetamine increases toxicity of bupropion by unspecified interaction mechanism. Use Caution/Monitor. May lower seizure threshold; keep bupropion dose as low as possible.butabarbitalMonitor Closely (1)butabarbital increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butalbitalMonitor Closely (1)butalbital increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butorphanolMonitor Closely (1)butorphanol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cabergolineSerious - Use Alternative (1)cabergoline, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.caffeineMonitor Closely (1)caffeine and methamphetamine both decrease sedation. Use Caution/Monitor.captoprilMonitor Closely (1)methamphetamine decreases effects of captopril by pharmacodynamic antagonism. Use Caution/Monitor. Methamphetamine may decrease the antihypertensive effects of ACE Inhibitors. Monitor blood pressure.carbinoxamineMonitor Closely (1)carbinoxamine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.celandineMinor (1)celandine increases effects of methamphetamine by unspecified interaction mechanism. Minor/Significance Unknown. Based on animal studies.celecoxibMonitor Closely (1)celecoxib will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.chloral hydrateMonitor Closely (1)chloral hydrate increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlordiazepoxideMonitor Closely (1)chlordiazepoxide increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chloroquineMonitor Closely (1)chloroquine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.chlorpheniramineMonitor Closely (1)chlorpheniramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpromazineMonitor Closely (2)chlorpromazine, 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. chlorpromazine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cimetidineMonitor Closely (1)cimetidine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.cinnarizineMonitor Closely (1)cinnarizine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.citalopramMonitor Closely (1)methamphetamine, citalopram. Either increases effects of the other by unknown mechanism. Use Caution/Monitor. Risk of serotonin syndrome.clemastineMonitor Closely (1)clemastine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clobazamMonitor Closely (1)clobazam will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly. clomipramineMonitor Closely (1)clomipramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)clomipramine, 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.clonazepamMonitor Closely (1)clonazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clorazepateMonitor Closely (1)clorazepate increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clozapineMonitor Closely (1)clozapine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.codeineMonitor Closely (1)codeine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyclizineMonitor Closely (1)cyclizine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyproheptadineMonitor Closely (1)cyproheptadine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dacomitinibSerious - Use Alternative (1)dacomitinib will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities. darifenacinMonitor Closely (1)darifenacin will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.desfluraneSerious - Use Alternative (1)desflurane increases toxicity of methamphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.desipramineMonitor Closely (1)desipramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)desipramine, 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.desmopressinMinor (1)desmopressin increases effects of methamphetamine by pharmacodynamic synergism. Minor/Significance Unknown.desvenlafaxineMonitor Closely (1)desvenlafaxine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mgdexchlorpheniramineMonitor Closely (1)dexchlorpheniramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexfenfluramineMonitor Closely (2)methamphetamine and dexfenfluramine both decrease sedation. Use Caution/Monitor. dexfenfluramine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dexlansoprazoleMinor (1)dexlansoprazole 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.dexmedetomidineMonitor Closely (1)dexmedetomidine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmethylphenidateMonitor Closely (2)dexmethylphenidate and methamphetamine both decrease sedation. Use Caution/Monitor. dexmethylphenidate and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dextroamphetamineMonitor Closely (2)dextroamphetamine and methamphetamine both decrease sedation. Use Caution/Monitor. dextroamphetamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dextroamphetamine transdermalMonitor Closely (1)methamphetamine, dextroamphetamine transdermal. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine transdermal and concomitant serotonergic drug(s).dextromoramideMonitor Closely (1)dextromoramide increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diamorphineMonitor Closely (1)diamorphine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diazepamMonitor Closely (1)diazepam increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diethylpropionMonitor Closely (2)methamphetamine and diethylpropion both decrease sedation. Use Caution/Monitor. diethylpropion and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.difenoxin hclMonitor Closely (1)difenoxin hcl increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dihydroergotamineSerious - Use Alternative (1)dihydroergotamine, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.dihydroergotamine intranasalSerious - Use Alternative (1)dihydroergotamine intranasal, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.diltiazemMonitor Closely (1)methamphetamine will decrease the level or effect of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor. Amphetamines may diminish antihypertensive effects of diltiazem. Monitor BP.dimenhydrinateMonitor Closely (1)dimenhydrinate increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenhydramineMonitor Closely (2)diphenhydramine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. diphenhydramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenoxylate hclMonitor Closely (1)diphenoxylate hcl increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dipipanoneMonitor Closely (1)dipipanone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dobutamineMonitor Closely (2)dobutamine and methamphetamine both decrease sedation. Use Caution/Monitor. dobutamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dopamineMonitor Closely (2)methamphetamine and dopamine both decrease sedation. Use Caution/Monitor. dopamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dopexamineMonitor Closely (2)dopexamine and methamphetamine both decrease sedation. Use Caution/Monitor. dopexamine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.doxapramSerious - Use Alternative (1)doxapram increases effects of methamphetamine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.doxepinMonitor Closely (1)doxepin increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)doxepin, 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.dronedaroneMonitor Closely (1)dronedarone will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.droperidolMonitor Closely (1)droperidol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.droxidopaMonitor Closely (1)methamphetamine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertensionduloxetineMonitor Closely (1)duloxetine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely.eliglustatMonitor Closely (1)eliglustat increases levels of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.elvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.ephedrineMonitor Closely (3)ephedrine, methamphetamine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. ephedrine and methamphetamine both decrease sedation. Use Caution/Monitor. ephedrine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrineMonitor Closely (2)epinephrine and methamphetamine both decrease sedation. Use Caution/Monitor. epinephrine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrine inhaledMonitor Closely (1)methamphetamine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrine racemicMonitor Closely (2)epinephrine racemic and methamphetamine both decrease sedation. Use Caution/Monitor. epinephrine racemic and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.ergoloid mesylatesSerious - Use Alternative (1)ergoloid mesylates, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.ergotamineSerious - Use Alternative (1)ergotamine, methamphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.esketamine intranasalMonitor Closely (1)esketamine intranasal, methamphetamine. Either increases toxicity of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Closely monitor blood pressure with concomitant use of esketamine nasal with stimulants. .esomeprazoleMinor (1)esomeprazole decreases levels of methamphetamine by Other (see comment). Minor/Significance Unknown. Comment: Time to maximum concentration (Tmax) of