benzphetamine (Rx)

Brand and Other Names:Didrex, Regimex

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet: Schedule III

  • 25mg (Regimex)
  • 50mg (Didrex)

Obesity

Indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction in patients with an initial body mass index (BMI) of ≥30 kg/m² who have not responded to appropriate weight reducing regimen (diet and/or exercise) alone

25-50 mg PO qDay initially; may increase dose or frequency according to response up to TID

Dosage Forms & Strengths

tablet: Schedule III

  • 25mg (Regimex)
  • 50mg (Didrex)

Obesity

Indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction in patients with an initial body mass index (BMI) of ≥30 kg/m² who have not responded to appropriate weight reducing regimen (diet and/or exercise) alone

<12 years: Safety and efficacy not established

≥12 years: 25-50 mg PO qDay initially; may increase dose or frequency according to response up to TID

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Interactions

Interaction Checker

and benzphetamine

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            Contraindicated (6)

            • isocarboxazid

              isocarboxazid increases effects of benzphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • linezolid

              linezolid increases effects of benzphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • methylphenidate

              benzphetamine increases effects of methylphenidate by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • phenelzine

              phenelzine increases effects of benzphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • selegiline transdermal

              selegiline transdermal increases effects of benzphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • tranylcypromine

              tranylcypromine increases effects of benzphetamine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            Serious - Use Alternative (33)

            • abametapir

              abametapir will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

            • amitriptyline

              amitriptyline, benzphetamine. 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.

            • amoxapine

              amoxapine, benzphetamine. 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.

            • apalutamide

              apalutamide will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

            • bosentan

              bosentan will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • cabergoline

              cabergoline, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • clomipramine

              clomipramine, benzphetamine. 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.

            • desflurane

              desflurane increases toxicity of benzphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

            • desipramine

              desipramine, benzphetamine. 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.

            • dihydroergotamine

              dihydroergotamine, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • dihydroergotamine intranasal

              dihydroergotamine intranasal, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • doxapram

              doxapram increases effects of benzphetamine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.

            • doxepin

              doxepin, benzphetamine. 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 mesylates

              ergoloid mesylates, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • ergotamine

              ergotamine, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • ether

              ether increases toxicity of benzphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

            • fexinidazole

              fexinidazole will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

            • idelalisib

              idelalisib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

            • imipramine

              imipramine, benzphetamine. 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 131

              benzphetamine 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.

            • ivosidenib

              ivosidenib will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

            • lofepramine

              lofepramine, benzphetamine. 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.

            • lonafarnib

              lonafarnib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.

            • maprotiline

              maprotiline, benzphetamine. 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.

            • methoxyflurane

              methoxyflurane increases toxicity of benzphetamine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

            • methylergonovine

              methylergonovine, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • nortriptyline

              nortriptyline, benzphetamine. 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.

            • protriptyline

              protriptyline, benzphetamine. 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.

            • trazodone

              trazodone, benzphetamine. 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.

            • trimipramine

              trimipramine, benzphetamine. 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.

            • tucatinib

              tucatinib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

            • voxelotor

              voxelotor will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

            • yohimbe

              yohimbe, benzphetamine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            Monitor Closely (192)

            • acetazolamide

              acetazolamide will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • albuterol

              albuterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              albuterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • alfentanil

              alfentanil increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • alprazolam

              alprazolam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • aluminum hydroxide

              aluminum hydroxide will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • amitriptyline

              amitriptyline increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • amobarbital

              amobarbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • amoxapine

              amoxapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • arformoterol

              arformoterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              arformoterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • aripiprazole

              aripiprazole increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • armodafinil

              armodafinil and benzphetamine both decrease sedation. Use Caution/Monitor.

            • azelastine

              azelastine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • baclofen

              baclofen increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • belladonna and opium

              belladonna and opium increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • benperidol

              benperidol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • brompheniramine

              brompheniramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • buprenorphine

              buprenorphine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • buprenorphine buccal

              buprenorphine buccal increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • butabarbital

              butabarbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • butalbital

              butalbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • butorphanol

              butorphanol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • caffeine

              caffeine and benzphetamine both decrease sedation. Use Caution/Monitor.

            • calcium carbonate

              calcium carbonate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • carbamazepine

              carbamazepine will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • carbinoxamine

              carbinoxamine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • carisoprodol

              carisoprodol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cenobamate

              cenobamate will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

            • chloral hydrate

              chloral hydrate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • chlordiazepoxide

              chlordiazepoxide increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • chlorpheniramine

              chlorpheniramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • chlorpromazine

              chlorpromazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpromazine, benzphetamine. 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.

            • chlorzoxazone

              chlorzoxazone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cinnarizine

              cinnarizine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clemastine

              clemastine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clomipramine

              clomipramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clonazepam

              clonazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clorazepate

              clorazepate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clozapine

              clozapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • codeine

              codeine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • crofelemer

              crofelemer increases levels of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

            • cyclizine

              cyclizine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cyclobenzaprine

              cyclobenzaprine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cyproheptadine

              cyproheptadine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dabrafenib

              dabrafenib will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • dantrolene

              dantrolene increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • darunavir

              darunavir will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • desipramine

              desipramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dexchlorpheniramine

              dexchlorpheniramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dexfenfluramine

              benzphetamine and dexfenfluramine both decrease sedation. Use Caution/Monitor.

              benzphetamine and dexfenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dexmedetomidine

              dexmedetomidine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dexmethylphenidate

              dexmethylphenidate and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and dexmethylphenidate both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dextroamphetamine

              dextroamphetamine and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and dextroamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dextromoramide

              dextromoramide increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diamorphine

              diamorphine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diazepam

              diazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diethylpropion

              benzphetamine and diethylpropion both decrease sedation. Use Caution/Monitor.

              benzphetamine and diethylpropion both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • difenoxin hcl

              difenoxin hcl increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diltiazem

              benzphetamine will decrease the level or effect of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor. Amphetamines may diminish antihypertensive effects of diltiazem. Monitor BP.

            • dimenhydrinate

              dimenhydrinate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diphenhydramine

              diphenhydramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diphenoxylate hcl

              diphenoxylate hcl increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dipipanone

              dipipanone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dobutamine

              dobutamine and benzphetamine both decrease sedation. Use Caution/Monitor.

              dobutamine and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dopamine

              benzphetamine and dopamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and dopamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dopexamine

              dopexamine and benzphetamine both decrease sedation. Use Caution/Monitor.

              dopexamine and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • doxepin

              doxepin increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • doxylamine

              doxylamine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • droperidol

              droperidol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • droxidopa

              benzphetamine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertension

            • elagolix

              elagolix will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • encorafenib

              encorafenib, benzphetamine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

            • ephedrine

              ephedrine and benzphetamine both decrease sedation. Use Caution/Monitor.

              ephedrine and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • epinephrine

              epinephrine and benzphetamine both decrease sedation. Use Caution/Monitor.

              epinephrine and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • epinephrine inhaled

              benzphetamine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • epinephrine racemic

              epinephrine racemic and benzphetamine both decrease sedation. Use Caution/Monitor.

              epinephrine racemic and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • estazolam

              estazolam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ethanol

              ethanol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • etomidate

              etomidate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • fedratinib

              fedratinib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

            • fenfluramine

              benzphetamine and fenfluramine both decrease sedation. Use Caution/Monitor.

              benzphetamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • fluphenazine

              fluphenazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              fluphenazine, benzphetamine. 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.

            • flurazepam

              flurazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • formoterol

              formoterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              formoterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • green tea

              green tea, benzphetamine. 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.

            • haloperidol

              haloperidol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • hydralazine

              hydralazine, benzphetamine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of hypertension.

            • hydromorphone

              hydromorphone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • hydroxyzine

              hydroxyzine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • iloperidone

              iloperidone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              iloperidone increases levels of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

            • imipramine

              imipramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • isoproterenol

              isoproterenol and benzphetamine both decrease sedation. Use Caution/Monitor.

              isoproterenol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • istradefylline

              istradefylline will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

            • ketotifen, ophthalmic

              ketotifen, ophthalmic increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • levalbuterol

              levalbuterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              levalbuterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • levorphanol

              levorphanol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lisdexamfetamine

              lisdexamfetamine and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and lisdexamfetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • lofepramine

              lofepramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lofexidine

              lofexidine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • loprazolam

              loprazolam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lorazepam

              lorazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lormetazepam

              lormetazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • loxapine

              loxapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • loxapine inhaled

              loxapine inhaled increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • maprotiline

              maprotiline increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • marijuana

              marijuana increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • melatonin

              melatonin increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • meperidine

              meperidine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • meprobamate

              meprobamate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • metaproterenol

              metaproterenol and benzphetamine both decrease sedation. Use Caution/Monitor.

              metaproterenol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • metaxalone

              metaxalone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • metformin

              benzphetamine 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.

            • methadone

              methadone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • methamphetamine

              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.

            • methocarbamol

              methocarbamol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • methyldopa

              methyldopa increases effects of benzphetamine by unknown mechanism. Use Caution/Monitor.

            • methylenedioxymethamphetamine

              methylenedioxymethamphetamine and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and methylenedioxymethamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • midazolam

              midazolam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • midodrine

              benzphetamine and midodrine both decrease sedation. Use Caution/Monitor.

              benzphetamine and midodrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • mirtazapine

              mirtazapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • mitotane

              mitotane decreases levels of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

            • modafinil

              modafinil and benzphetamine both decrease sedation. Use Caution/Monitor.

            • morphine

              morphine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • motherwort

              motherwort increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • moxonidine

              moxonidine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nabilone

              nabilone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nalbuphine

              nalbuphine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • norepinephrine

              norepinephrine and benzphetamine both decrease sedation. Use Caution/Monitor.

              norepinephrine and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • nortriptyline

              nortriptyline increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • olanzapine

              olanzapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • opium tincture

              opium tincture increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • orphenadrine

              orphenadrine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • oxazepam

              oxazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • oxycodone

              oxycodone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • oxymorphone

              oxymorphone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • oxytocin

              oxytocin increases effects of benzphetamine by pharmacodynamic synergism. Use Caution/Monitor.

            • paliperidone

              paliperidone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • papaveretum

              papaveretum increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • papaverine

              papaverine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pentazocine

              pentazocine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pentobarbital

              pentobarbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • perphenazine

              perphenazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              perphenazine, benzphetamine. 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.

            • phendimetrazine

              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.

            • phenobarbital

              phenobarbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phentermine

              phentermine and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and phentermine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • phenylephrine

              benzphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

              benzphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • phenylephrine PO

              benzphetamine and phenylephrine PO both decrease sedation. Use Caution/Monitor.

              benzphetamine and phenylephrine PO both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • pholcodine

              pholcodine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pimozide

              pimozide increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pirbuterol

              pirbuterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              pirbuterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • primidone

              primidone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • prochlorperazine

              prochlorperazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              prochlorperazine, benzphetamine. 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.

            • promazine

              promazine, benzphetamine. 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.

            • promethazine

              promethazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              promethazine, benzphetamine. 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.

            • propylhexedrine

              benzphetamine and propylhexedrine both decrease sedation. Use Caution/Monitor.

              benzphetamine and propylhexedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • protriptyline

              protriptyline increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pseudoephedrine

              benzphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • quazepam

              quazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • quetiapine

              quetiapine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ramelteon

              ramelteon increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • risperidone

              risperidone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • rucaparib

              rucaparib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

            • salmeterol

              salmeterol and benzphetamine both decrease sedation. Use Caution/Monitor.

              salmeterol and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • scullcap

              scullcap increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • secobarbital

              secobarbital increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • serdexmethylphenidate/dexmethylphenidate

              serdexmethylphenidate/dexmethylphenidate and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and serdexmethylphenidate/dexmethylphenidate both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • shepherd's purse

              shepherd's purse increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • sodium bicarbonate

              sodium bicarbonate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • sodium citrate/citric acid

              sodium citrate/citric acid will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • sodium lactate

              sodium lactate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

            • solriamfetol

              benzphetamine and solriamfetol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • stiripentol

              stiripentol, benzphetamine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

            • sufentanil

              sufentanil increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • tapentadol

              tapentadol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • tazemetostat

              tazemetostat will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tecovirimat

              tecovirimat will decrease the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

            • temazepam

              temazepam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • terbutaline

              terbutaline and benzphetamine both decrease sedation. Use Caution/Monitor.

              terbutaline and benzphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • thioridazine

              thioridazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              thioridazine, benzphetamine. 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.

            • thiothixene

              thiothixene increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • topiramate

              topiramate increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

            • tramadol

              tramadol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • trazodone

              trazodone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • triazolam

              triazolam increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • triclofos

              triclofos increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • trifluoperazine

              trifluoperazine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              trifluoperazine, benzphetamine. 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.

            • trimipramine

              trimipramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • triprolidine

              triprolidine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • xylometazoline

              benzphetamine and xylometazoline both decrease sedation. Use Caution/Monitor.

              benzphetamine and xylometazoline both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • yohimbine

              yohimbine and benzphetamine both decrease sedation. Use Caution/Monitor.

              benzphetamine and yohimbine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • ziconotide

              ziconotide increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ziprasidone

              ziprasidone increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            Minor (9)

            • acetazolamide

              acetazolamide will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • anastrozole

              anastrozole will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • cyclophosphamide

              cyclophosphamide will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • desmopressin

              desmopressin increases effects of benzphetamine by pharmacodynamic synergism. Minor/Significance Unknown.

            • eucalyptus

              eucalyptus increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.

            • larotrectinib

              larotrectinib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • levoketoconazole

              levoketoconazole will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ribociclib

              ribociclib will increase the level or effect of benzphetamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • sage

              sage increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.

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            Adverse Effects

            Frequency Not Defined

            Abdominal pain

            Blood pressure incr

            Constipation

            Diarrhea

            Dizziness

            Dry mouth

            Headache

            Insomnia

            Ischemic cardiac events associated with chronic amphetamine use

            Libido changes

            Nausea

            Palpitations

            Psychotic episodes (rare)

            Restlessness

            Tachycardia

            Tremor

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            Warnings

            Contraindications

            Advanced arteriosclerosis

            Symptomatic cardiovascular disease including arrhythmias

            Hyperthyroidism

            Moderate to severe hypertension

            Hypersensitivity to sympathomimetic amines

            Glaucoma

            Agitated state

            History of drug abuse

            Pregnancy/lactation; women planning to get pregnant

            Use within 14 days of MAOIs

            Do not use in combination with other anorectic agents including prescription, OTC, or herbal

            Use of anorectic agents associated with increased risk of developing pulmonary hypertension (PH) (rare, but often fatal disorder); use >3 months associated with 23-fold increased risk of developing PH (benzphetamine not specifically studied)

            Immediately discontinue if onset or aggravation of exertional dyspnea, or unexplained symptoms of angina pectoris, syncope, or lower extremity edema emerge suggesting possible PH

            Valvular heart disease associated with use of some anorectics (no cases reported with benzphetamine monotherapy)

            Not recommended for patients who used any anorectic agents within prior year

            Cautions

            Discontinue when tolerance develops - DO NOT EXCEED recommended dose

            Diabetics: insulin requirements may be altered

            Mild hypertension

            May impair ability to drive &/or operate heavy machinery

            Alkaline urine will increase half-life

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            Pregnancy & Lactation

            Pregnancy

            Contraindicated

            Lactation

            Excreted in human milk; mothers taking amphetamines should be advised to refrain from nursing

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Amphetamine anorexigenic agent

            Pharmacokinetics

            Metabolism: by cytochrome P450 enzymes

            Excretion: 5-30% unchanged in urine, highly dependent on pH

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            benzphetamine oral
            -
            50 mg tablet
            benzphetamine oral
            -
            50 mg tablet

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Patient Education
            benzphetamine oral

            BENZPHETAMINE - ORAL

            (benz-FET-a-meen)

            COMMON BRAND NAME(S): Didrex

            USES: Benzphetamine is used short-term along with a doctor-approved, reduced-calorie diet, exercise, and behavior change program to help you lose weight. It is used in people who are significantly overweight (obese) and have not been able to lose enough weight with diet and exercise alone. Losing weight and keeping it off can reduce the many health risks that come with obesity, including heart disease, diabetes, high blood pressure, and a shorter life.It is not known how this medication helps people to lose weight. It may work by decreasing your appetite, increasing the amount of energy used by your body, or by affecting certain parts of the brain. This medication is an appetite suppressant and belongs to a class of drugs called sympathomimetic amines.

            HOW TO USE: Take this medication by mouth as directed by your doctor, usually 1 to 3 times a day. Taking this medication late in the day may cause trouble sleeping (insomnia).The dosage is based on your medical condition and response to therapy. Your doctor will adjust the dose to find the best dose for you. Use this medication regularly and exactly as prescribed in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.Benzphetamine is usually taken for only a few weeks at a time. It should not be taken with other appetite suppressants (see also Drug Interactions section). The possibility of serious side effects increases with longer use of this medication and use of this drug along with certain other diet drugs.If you suddenly stop using this medication, you may have withdrawal symptoms (such as depression, severe tiredness). To help prevent withdrawal, your doctor may lower your dose slowly. Withdrawal is more likely if you have used benzphetamine for a long time or in high doses. Tell your doctor or pharmacist right away if you have withdrawal.Though it helps many people, this medication may sometimes cause addiction. This risk may be higher if you have a substance use disorder (such as overuse of or addiction to drugs/alcohol). Do not increase your dose, take it more often, or use it for a longer time than prescribed. Properly stop the medication when so directed.This medication may stop working well after you have been taking it for a while. Talk with your doctor if this medication stops working well. Do not increase the dose unless directed by your doctor. Your doctor may direct you to stop taking this medication.

            SIDE EFFECTS: Dizziness, dry mouth, difficulty sleeping, irritability, nausea, vomiting, diarrhea, or constipation may occur. If these effects last or get worse, notify your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high.Tell your doctor right away if you have any serious side effects, including: fast/irregular/pounding heartbeat, mental/mood changes (such as agitation, uncontrolled anger, hallucinations, nervousness), uncontrolled muscle movements, change in sexual ability/interest.Get medical help right away if you have any very serious side effects, including: severe headache, trouble speaking, seizure, weakness on one side of the body, vision changes (such as blurred vision).This drug may rarely cause serious (sometimes fatal) lung or heart problems (pulmonary hypertension, heart valve problems). The risk increases with longer use of this medication and use of this drug along with other appetite-suppressant drugs/herbal products. If you notice any of the following unlikely but very serious side effects, stop taking this medication and consult your doctor or pharmacist right away: chest pain, difficulty breathing with exercise, decreased ability to exercise, fainting, swelling of the legs/ankles/feet.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: Before taking benzphetamine, tell your doctor or pharmacist if you are allergic to it; or to any other sympathomimetic amines (including decongestants such as pseudoephedrine, stimulants such as amphetamine, appetite suppressants such as phentermine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (such as chest pain, heart attack, heart murmur, fast/irregular heartbeat, heart valve problems), high blood pressure, glaucoma, personal or family history of a substance use disorder (such as overuse of or addiction to drugs/alcohol), mental/mood problems (such as severe anxiety, bipolar disorder, psychosis, schizophrenia), high blood pressure in the lungs (pulmonary hypertension), stroke, overactive thyroid (hyperthyroidism), diabetes, kidney disease, seizures.This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).If you have diabetes, check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication during treatment with this drug.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be at greater risk for dizziness and high blood pressure while using this drug.Benzphetamine must not be used during pregnancy. It may harm an unborn baby. If you become pregnant or think you may be pregnant, inform your doctor right away. Infants born to mothers who have been using this medication for a long time or in high doses may have withdrawal symptoms such as irritability or extreme tiredness. Tell your doctor right away if you notice any of these symptoms in your newborn.This drug may pass into breast milk and could have undesirable effects on a nursing infant. Breast-feeding is not recommended while using this drug. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: phenothiazines (such as prochlorperazine, chlorpromazine), other stimulants (including amphetamines, methylphenidate, street drugs such as cocaine or MDMA/"ecstasy").If you are taking or have taken other appetite-suppressant drugs in the past year (such as phentermine, ephedra/ma huang), tell your doctor or pharmacist before starting this medication.Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication.Some products have ingredients that could raise your heart rate or blood pressure. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products or diet aids).Caffeine can increase the side effects of this medication. Avoid drinking large amounts of beverages containing caffeine (coffee, tea, colas) or eating large amounts of chocolate.

            OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: rapid breathing, unusual restlessness, fast/slow/irregular heartbeat, chest pain, hallucinations, seizures, loss of consciousness.

            NOTES: Do not share this medication with others. Sharing it is against the law.Appetite suppressants should not be used in place of proper diet. For best results, this drug must be used along with a doctor-approved diet and exercise program.Lab and/or medical tests (such as blood pressure, heart/kidney function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

            MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose or late in the evening, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store at room temperature away from light and moisture. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

            Information last revised November 2022. Copyright(c) 2023 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.