use caution. Minor/Significance Unknown.albuterolMonitor Closely (2)albuterol and phendimetrazine both decrease sedation. Use Caution/Monitor. albuterol and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.alfentanilMonitor Closely (1)alfentanil increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.alprazolamMonitor Closely (1)alprazolam increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptylineMonitor Closely (1)amitriptyline increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, phendimetrazine. 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.amobarbitalMonitor Closely (1)amobarbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amoxapineMonitor Closely (1)amoxapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amoxapine, phendimetrazine. 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.arformoterolMonitor Closely (2)arformoterol and phendimetrazine both decrease sedation. Use Caution/Monitor. arformoterol and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.aripiprazoleMonitor Closely (1)aripiprazole increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.armodafinilMonitor Closely (1)armodafinil and phendimetrazine both decrease sedation. Use Caution/Monitor.azelastineMonitor Closely (1)azelastine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.belladonna and opiumMonitor Closely (1)belladonna and opium increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benazeprilMonitor Closely (1)phendimetrazine decreases effects of benazepril by pharmacodynamic antagonism. Use Caution/Monitor.benperidolMonitor Closely (1)benperidol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benzphetamineMonitor Closely (2)benzphetamine and phendimetrazine both decrease sedation. Use Caution/Monitor. benzphetamine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.brompheniramineMonitor Closely (1)brompheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine buccalMonitor Closely (1)buprenorphine buccal increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine subdermal implantMonitor Closely (1)phendimetrazine, 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)phendimetrazine, 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.butabarbitalMonitor Closely (1)butabarbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butalbitalMonitor Closely (1)butalbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butorphanolMonitor Closely (1)butorphanol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cabergolineSerious - Use Alternative (1)cabergoline, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.caffeineMonitor Closely (1)caffeine and phendimetrazine both decrease sedation. Use Caution/Monitor.captoprilMonitor Closely (1)phendimetrazine decreases effects of captopril by pharmacodynamic antagonism. Use Caution/Monitor. Phendimetrazine may decrease the antihypertensive effects of ACE Inhibitors.carbinoxamineMonitor Closely (1)carbinoxamine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chloral hydrateMonitor Closely (1)chloral hydrate increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlordiazepoxideMonitor Closely (1)chlordiazepoxide increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpheniramineMonitor Closely (1)chlorpheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpromazineMonitor Closely (2)chlorpromazine, phendimetrazine. 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 phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cinnarizineMonitor Closely (1)cinnarizine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clemastineMonitor Closely (1)clemastine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clomipramineMonitor Closely (1)clomipramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)clomipramine, phendimetrazine. 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 phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clorazepateMonitor Closely (1)clorazepate increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clozapineMonitor Closely (1)clozapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.codeineMonitor Closely (1)codeine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyclizineMonitor Closely (1)cyclizine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyproheptadineMonitor Closely (1)cyproheptadine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.desfluraneSerious - Use Alternative (1)desflurane increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.desipramineMonitor Closely (1)desipramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)desipramine, phendimetrazine. 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 phendimetrazine by pharmacodynamic synergism. Minor/Significance Unknown.dexchlorpheniramineMonitor Closely (1)dexchlorpheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexfenfluramineMonitor Closely (2)dexfenfluramine and phendimetrazine both decrease sedation. Use Caution/Monitor. dexfenfluramine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dexmedetomidineMonitor Closely (1)dexmedetomidine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmethylphenidateMonitor Closely (2)dexmethylphenidate and phendimetrazine both decrease sedation. Use Caution/Monitor. dexmethylphenidate and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dextroamphetamineMonitor Closely (2)dextroamphetamine and phendimetrazine both decrease sedation. Use Caution/Monitor. dextroamphetamine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dextromoramideMonitor Closely (1)dextromoramide increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diamorphineMonitor Closely (1)diamorphine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diethylpropionMonitor Closely (2)diethylpropion and phendimetrazine both decrease sedation. Use Caution/Monitor. diethylpropion and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.difenoxin hclMonitor Closely (1)difenoxin hcl increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dihydroergotamineSerious - Use Alternative (1)dihydroergotamine, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.dihydroergotamine intranasalSerious - Use Alternative (1)dihydroergotamine intranasal, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.diltiazemMonitor Closely (1)phendimetrazine 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 phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenhydramineMonitor Closely (1)diphenhydramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenoxylate hclMonitor Closely (1)diphenoxylate hcl increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dipipanoneMonitor Closely (1)dipipanone increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dobutamineMonitor Closely (2)dobutamine and phendimetrazine both decrease sedation. Use Caution/Monitor. dobutamine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dopamineMonitor Closely (2)dopamine and phendimetrazine both decrease sedation. Use Caution/Monitor. dopamine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.dopexamineMonitor Closely (2)dopexamine and phendimetrazine both decrease sedation. Use Caution/Monitor. dopexamine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.doxapramSerious - Use Alternative (1)doxapram increases effects of phendimetrazine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.doxepinMonitor Closely (1)doxepin increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)doxepin, phendimetrazine. 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.droperidolMonitor Closely (1)droperidol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ephedrineMonitor Closely (3)ephedrine, phendimetrazine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. ephedrine and phendimetrazine both decrease sedation. Use Caution/Monitor. ephedrine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrineMonitor Closely (2)epinephrine and phendimetrazine both decrease sedation. Use Caution/Monitor. epinephrine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.epinephrine inhaledMonitor Closely (1)phendimetrazine, 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 phendimetrazine both decrease sedation. Use Caution/Monitor. epinephrine racemic and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.ergoloid mesylatesSerious - Use Alternative (1)ergoloid mesylates, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.ergotamineSerious - Use Alternative (1)ergotamine, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.esketamine intranasalMonitor Closely (1)esketamine intranasal, phendimetrazine. 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. .estazolamMonitor Closely (1)estazolam increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ethanolMonitor Closely (1)ethanol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.etherSerious - Use Alternative (1)ether increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.eucalyptusMinor (1)eucalyptus increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.fenfluramineMonitor Closely (2)fenfluramine and phendimetrazine both decrease sedation. Use Caution/Monitor. fenfluramine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.fluphenazineMonitor Closely (2)fluphenazine, phendimetrazine. 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 phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.flurazepamMonitor Closely (1)flurazepam increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.formoterolMonitor Closely (2)formoterol and phendimetrazine both decrease sedation. Use Caution/Monitor. formoterol and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.green teaMonitor Closely (1)green tea, phendimetrazine. 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.haloperidolMonitor Closely (1)haloperidol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydralazineMonitor Closely (1)hydralazine, phendimetrazine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.hydromorphoneMonitor Closely (1)hydromorphone increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydroxyzineMonitor Closely (1)hydroxyzine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.iloperidoneMonitor Closely (1)iloperidone increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.imipramineMonitor Closely (1)imipramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)imipramine, phendimetrazine. 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)phendimetrazine 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)phendimetrazine will decrease the level or effect of iobenguane I 131 by Other (see comment). Avoid or Use