AdultPediatricDosage Forms & Strengths capsules, extended release: Schedule III 105mg tablet: Schedule III 35mg Obesity Tablet: 35 mg q8-12hr 1 hr AC Range: 17.5 mg q12hr to 70 mg q8hr; not to exceed 70 mg PO q8hr Extended release capsule: 105 mg qAMBecause pediatric obesity is a chronic condition requiring long-term treatment, the use of amphetamines approved for short-term therapy is not recommended in patients <17 years of ageInteraction CheckerEnter a drug name and phendimetrazineNo Results No Interactions Found Interactions FoundContraindicatedSerious - Use AlternativeSignificant - Monitor CloselyMinorAll Interactions Sort By: SeverityName Contraindicated (9)iobenguane I 123phendimetrazine 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.isocarboxazidisocarboxazid increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.linezolidlinezolid increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.methylphenidatephendimetrazine increases effects of methylphenidate by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.phenelzinephenelzine increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.procarbazineprocarbazine increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.safinamidephendimetrazine, safinamide. Either increases toxicity of the other by serotonin levels. Contraindicated. Concomitant use could result in life-threatening serotonin syndrome.selegiline transdermalselegiline transdermal increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.tranylcyprominetranylcypromine increases effects of phendimetrazine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.Serious - Use Alternative (28)amitriptylineamitriptyline, 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.amoxapineamoxapine, 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.cabergolinecabergoline, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.clomipramineclomipramine, 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.desfluranedesflurane increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.desipraminedesipramine, 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.dihydroergotaminedihydroergotamine, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.dihydroergotamine intranasaldihydroergotamine intranasal, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.doxapramdoxapram increases effects of phendimetrazine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.doxepindoxepin, 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.ergoloid mesylatesergoloid mesylates, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.ergotamineergotamine, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.etherether increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.imipramineimipramine, 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 131phendimetrazine 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.isofluraneisoflurane increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.lofepraminelofepramine, 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.maprotilinemaprotiline, 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.methoxyfluranemethoxyflurane increases toxicity of phendimetrazine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.methylergonovinemethylergonovine, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.nortriptylinenortriptyline, 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.ozanimodozanimod increases toxicity of phendimetrazine 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.protriptylineprotriptyline, 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.rasagilinerasagiline increases effects of phendimetrazine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Phendimetrazine should not be administered during or within 14 days following the use of most MAOIs or drugs with MAO-inhibiting activity. Risk of acute hypertensive episode.selegilineselegiline increases effects of phendimetrazine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Phendimetrazine should not be administered during or within 14 days following the use of most MAOIs or drugs with MAO-inhibiting activity. Risk of acute hypertensive episode. .trazodonetrazodone, 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.trimipraminetrimipramine, 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.yohimbeyohimbe, phendimetrazine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.Monitor Closely (162)albuterolalbuterol 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.alfentanilalfentanil increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.alprazolamalprazolam increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptylineamitriptyline increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amobarbitalamobarbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amoxapineamoxapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.arformoterolarformoterol 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.aripiprazolearipiprazole increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.armodafinilarmodafinil and phendimetrazine both decrease sedation. Use Caution/Monitor.azelastineazelastine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.belladonna and opiumbelladonna and opium increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benazeprilphendimetrazine decreases effects of benazepril by pharmacodynamic antagonism. Use Caution/Monitor.benperidolbenperidol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.benzphetaminebenzphetamine 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.brompheniraminebrompheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine buccalbuprenorphine buccal increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.buprenorphine subdermal implantphendimetrazine, 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 injectionphendimetrazine, 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.butabarbitalbutabarbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butalbitalbutalbital increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.butorphanolbutorphanol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.caffeinecaffeine and phendimetrazine both decrease sedation. Use Caution/Monitor.captoprilphendimetrazine decreases effects of captopril by pharmacodynamic antagonism. Use Caution/Monitor. Phendimetrazine may decrease the antihypertensive effects of ACE Inhibitors.carbinoxaminecarbinoxamine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chloral hydratechloral hydrate increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlordiazepoxidechlordiazepoxide increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpheniraminechlorpheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.chlorpromazinechlorpromazine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.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.cinnarizinecinnarizine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clemastineclemastine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clomipramineclomipramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clonazepamclonazepam increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clorazepateclorazepate increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.clozapineclozapine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.codeinecodeine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyclizinecyclizine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.cyproheptadinecyproheptadine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.desipraminedesipramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexchlorpheniraminedexchlorpheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexfenfluraminedexfenfluramine 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.dexmedetomidinedexmedetomidine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dexmethylphenidatedexmethylphenidate 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.dextroamphetaminedextroamphetamine 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.dextromoramidedextromoramide increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diamorphinediamorphine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diethylpropiondiethylpropion 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 hcldifenoxin hcl increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diltiazemphendimetrazine will decrease the level or effect of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor. Amphetamines may diminish antihypertensive effects of diltiazem. Monitor BP.dimenhydrinatedimenhydrinate increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenhydraminediphenhydramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.diphenoxylate hcldiphenoxylate hcl increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dipipanonedipipanone increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.dobutaminedobutamine 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.dopaminedopamine 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.dopexaminedopexamine 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.doxepindoxepin increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.droperidoldroperidol increases and phendimetrazine decreases sedation. Effect of interaction