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    Drugs & Diseases

    clemastine (Rx, OTC)

    Brand and Other Names:
    • Print

    Dosing & Uses

    AdultPediatricGeriatric

    Dosage Forms & Strengths

    tablet

    • 1.34mg
    • 2.68mg

    syrup

    • 0.67mg/5mL

    Allergic Rhinitis

    1.34 mg PO q12hr; not to exceed 8.04 mg/day for syrup or 2.68 mg/24 hours for tablets

    Urticaria

    2.68 mg PO qDay-q8hr; not to exceed 8.04 mg/day

    Angioedema

    2.68 mg PO qDay-q8hr; not to exceed 8.04 mg/day

    Other Indications & Uses

    Perennial & seasonal allergic & vasomotor rhinitis, relief of symptoms from colds, urticaria, angioedema, anaphylactic reactions, pruritus, allergic conjunctivitis

    Dosage Forms & Strengths

    tablet

    • 1.34mg
    • 2.68mg

    syrup

    • 0.67mg/5mL

    Allergic Rhinitis

    <6 years old: 0.05 mg/kg/day as clemastine base or 0.335-0.67 mg/day clemastine fumarate (0.25-0.5 mg base/day) divided q8-12hr; not to exceed 1.34 mg (1 mg base)  

    6-12 years old: 0.67-1.34 mg clemastine fumarate (0.5-1 mg base) q12hr; not to exceed 4.02 mg/day (3 mg/day base)

    >12 years old: As in adults

    Urticaria

    <6 years old: 0.05 mg/kg/day as clemastine base or 0.335-0.67 mg/day clemastine fumarate (0.25-0.5 mg base/day) divided q8-12hr; not to exceed 1.34 mg (1 mg base)  

    6-12 years old: 0.67-1.34 mg clemastine fumarate (0.5-1 mg base) q12hr; not to exceed 4.02 mg/day (3 mg/day base)

    >12 years old: As in adults

    Administer lower doses to patients >60 years

    Nonanticholinergic antihistamines should be considered first when treating allergic reactions (Beers Criteria)

    Avoid use in elderly because of high incidence of anticholinergic effects

    Clearance reduced with advanced age, greater risk of confusion, dry mouth, constipation, and other anticholinergic effects and toxicity

    May exacerbate existing lower urinary conditions or benign prostatic hyperplasia

    Allergic Rhinitis

    1.34 mg PO q12hr; not to exceed 8.04 mg/day for syrup or 2.68 mg/24 hours for tablets

    Urticaria

    2.68 mg PO qDay-q8hr; not to exceed 8.04 mg/day

    Angioedema

    2.68 mg PO qDay-q8hr; not to exceed 8.04 mg/day

    Next:

    Interactions

    Interaction Checker

    and clemastine

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                Serious - Use Alternative (8)

                • calcium/magnesium/potassium/sodium oxybates

                  clemastine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

                • eluxadoline

                  clemastine, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions.

                • isocarboxazid

                  isocarboxazid increases effects of clemastine by Other (see comment). Avoid or Use Alternate Drug. Comment: Isocarboxazid should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

                • lonafarnib

                  clemastine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

                • metoclopramide intranasal

                  clemastine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

                • pitolisant

                  clemastine decreases effects of pitolisant by Other (see comment). Avoid or Use Alternate Drug. Comment: Pitolisant increases histamine levels in the brain; therefore, H1 receptor antagonists that cross the blood-brain barrier may reduce the efficacy of pitolisant.

                • sodium oxybate

                  clemastine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

                • tranylcypromine

                  tranylcypromine increases effects of clemastine by Other (see comment). Avoid or Use Alternate Drug. Comment: Tranylcypromine should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

                Monitor Closely (202)

                • albuterol

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

                • alfentanil

                  clemastine and alfentanil both increase sedation. Use Caution/Monitor.

                • alprazolam

                  clemastine and alprazolam both increase sedation. Use Caution/Monitor.

                • amifampridine

                  clemastine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

                • amitriptyline

                  clemastine and amitriptyline both increase sedation. Use Caution/Monitor.

                • amobarbital

                  clemastine and amobarbital both increase sedation. Use Caution/Monitor.

                • amoxapine

                  clemastine and amoxapine both increase sedation. Use Caution/Monitor.

                • apomorphine

                  clemastine and apomorphine both increase sedation. Use Caution/Monitor.

                • arformoterol

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

                • aripiprazole

                  clemastine and aripiprazole both increase sedation. Use Caution/Monitor.

                • armodafinil

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

                • avapritinib

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

                • axitinib

                  clemastine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

                • azelastine

                  azelastine and clemastine both increase sedation. Use Caution/Monitor.

                • baclofen

                  clemastine and baclofen both increase sedation. Use Caution/Monitor.

                • belladonna and opium

                  clemastine and belladonna and opium both increase sedation. Use Caution/Monitor.

                • benperidol

                  clemastine and benperidol both increase sedation. Use Caution/Monitor.

                • benzphetamine

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

                • brexanolone

                  brexanolone, clemastine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

                • brompheniramine

                  brompheniramine and clemastine both increase sedation. Use Caution/Monitor.

                • buprenorphine

                  clemastine and buprenorphine both increase sedation. Use Caution/Monitor.

                • buprenorphine buccal

                  clemastine and buprenorphine buccal both increase sedation. Use Caution/Monitor.

                • butabarbital

                  clemastine and butabarbital both increase sedation. Use Caution/Monitor.

                • butalbital

                  clemastine and butalbital both increase sedation. Use Caution/Monitor.

                • butorphanol

                  clemastine and butorphanol both increase sedation. Use Caution/Monitor.

                • caffeine

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

                • carbinoxamine

                  carbinoxamine and clemastine both increase sedation. Use Caution/Monitor.

                • carisoprodol

                  clemastine and carisoprodol both increase sedation. Use Caution/Monitor.

                • cenobamate

                  cenobamate, clemastine. Either increases effects of the other by sedation. Use Caution/Monitor.

                • chloral hydrate

                  clemastine and chloral hydrate both increase sedation. Use Caution/Monitor.

                • chlordiazepoxide

                  clemastine and chlordiazepoxide both increase sedation. Use Caution/Monitor.

                • chlorpheniramine

                  chlorpheniramine and clemastine both increase sedation. Use Caution/Monitor.

                • chlorpromazine

                  clemastine and chlorpromazine both increase sedation. Use Caution/Monitor.

                • chlorzoxazone

                  clemastine and chlorzoxazone both increase sedation. Use Caution/Monitor.

                • cinnarizine

                  cinnarizine and clemastine both increase sedation. Use Caution/Monitor.

                • clobazam

                  clemastine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

                • clomipramine

                  clemastine and clomipramine both increase sedation. Use Caution/Monitor.

                • clonazepam

                  clemastine and clonazepam both increase sedation. Use Caution/Monitor.

                • clorazepate

                  clemastine and clorazepate both increase sedation. Use Caution/Monitor.

                • clozapine

                  clemastine and clozapine both increase sedation. Use Caution/Monitor.

                • codeine

                  clemastine and codeine both increase sedation. Use Caution/Monitor.

                • cyclizine

                  clemastine and cyclizine both increase sedation. Use Caution/Monitor.

                • cyclobenzaprine

                  clemastine and cyclobenzaprine both increase sedation. Use Caution/Monitor.

                • cyproheptadine

                  clemastine and cyproheptadine both increase sedation. Use Caution/Monitor.

                • dantrolene

                  clemastine and dantrolene both increase sedation. Use Caution/Monitor.

                • desflurane

                  desflurane and clemastine both increase sedation. Use Caution/Monitor.

                • desipramine

                  clemastine and desipramine both increase sedation. Use Caution/Monitor.

                • deutetrabenazine

                  clemastine and deutetrabenazine both increase sedation. Use Caution/Monitor.

                • dexchlorpheniramine

                  clemastine and dexchlorpheniramine both increase sedation. Use Caution/Monitor.

                • dexfenfluramine

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

                • dexmedetomidine

                  clemastine and dexmedetomidine both increase sedation. Use Caution/Monitor.

                • dexmethylphenidate

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

                • dextroamphetamine

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

                • dextromoramide

                  clemastine and dextromoramide both increase sedation. Use Caution/Monitor.

                • diamorphine

                  clemastine and diamorphine both increase sedation. Use Caution/Monitor.

                • diazepam

                  clemastine and diazepam both increase sedation. Use Caution/Monitor.

                • diazepam intranasal

                  diazepam intranasal, clemastine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

                • diethylpropion

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

                • difenoxin hcl

                  clemastine and difenoxin hcl both increase sedation. Use Caution/Monitor.

                • dimenhydrinate

                  clemastine and dimenhydrinate both increase sedation. Use Caution/Monitor.

                • diphenhydramine

                  clemastine and diphenhydramine both increase sedation. Use Caution/Monitor.

                • diphenoxylate hcl

                  clemastine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

                • dipipanone

                  clemastine and dipipanone both increase sedation. Use Caution/Monitor.

                • dobutamine

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

                • dopamine

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

                • dopexamine

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

                • dosulepin

                  clemastine and dosulepin both increase sedation. Use Caution/Monitor.

                • doxepin

                  clemastine and doxepin both increase sedation. Use Caution/Monitor.

                • doxylamine

                  clemastine and doxylamine both increase sedation. Use Caution/Monitor.

                • droperidol

                  clemastine and droperidol both increase sedation. Use Caution/Monitor.

                • ephedrine

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

                • epinephrine

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

                • epinephrine racemic

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

                • esketamine intranasal

                  esketamine intranasal, clemastine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

                • estazolam

                  clemastine and estazolam both increase sedation. Use Caution/Monitor.

                • ethanol

                  clemastine and ethanol both increase sedation. Use Caution/Monitor.

                • etomidate

                  etomidate and clemastine both increase sedation. Use Caution/Monitor.

                • fenfluramine

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

                • fentanyl

                  fentanyl, clemastine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

                • fentanyl intranasal

                  fentanyl intranasal, clemastine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

                • fentanyl transdermal

                  fentanyl transdermal, clemastine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

                • fentanyl transmucosal

                  fentanyl transmucosal, clemastine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

                • finerenone

                  clemastine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

                • flibanserin

                  clemastine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.

                  clemastine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

                • fluphenazine

                  clemastine and fluphenazine both increase sedation. Use Caution/Monitor.

                • flurazepam

                  clemastine and flurazepam both increase sedation. Use Caution/Monitor.

                • formoterol

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

                • gabapentin

                  gabapentin, clemastine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

                • gabapentin enacarbil

                  gabapentin enacarbil, clemastine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

                • glycopyrronium tosylate topical

                  glycopyrronium tosylate topical, clemastine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

                • gotu kola

                  gotu kola increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • haloperidol

                  clemastine and haloperidol both increase sedation. Use Caution/Monitor.

                • hawthorn

                  hawthorn increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • hops

                  hops increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • hyaluronidase

                  clemastine decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Antihistamines, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect.

                • hydromorphone

                  clemastine and hydromorphone both increase sedation. Use Caution/Monitor.

                • hydroxyzine

                  clemastine and hydroxyzine both increase sedation. Use Caution/Monitor.

                • iloperidone

                  clemastine and iloperidone both increase sedation. Use Caution/Monitor.

                • imipramine

                  clemastine and imipramine both increase sedation. Use Caution/Monitor.

                • isoproterenol

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

                • ivacaftor

                  clemastine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

                • kava

                  kava increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • ketamine

                  ketamine and clemastine both increase sedation. Use Caution/Monitor.

                • ketotifen, ophthalmic

                  clemastine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

                • lasmiditan

                  lasmiditan, clemastine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

                • lemborexant

                  clemastine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

                  lemborexant, clemastine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

                • levalbuterol

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

                • levorphanol

                  clemastine and levorphanol both increase sedation. Use Caution/Monitor.

                • lisdexamfetamine

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

                • lofepramine

                  clemastine and lofepramine both increase sedation. Use Caution/Monitor.

                • lofexidine

                  clemastine and lofexidine both increase sedation. Use Caution/Monitor.

                • lomitapide

                  clemastine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

                • loprazolam

                  clemastine and loprazolam both increase sedation. Use Caution/Monitor.

                • lorazepam

                  clemastine and lorazepam both increase sedation. Use Caution/Monitor.

                • lormetazepam

                  clemastine and lormetazepam both increase sedation. Use Caution/Monitor.

                • loxapine

                  clemastine and loxapine both increase sedation. Use Caution/Monitor.

                • loxapine inhaled

                  clemastine and loxapine inhaled both increase sedation. Use Caution/Monitor.

                • lurasidone

                  lurasidone, clemastine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

                • maprotiline

                  clemastine and maprotiline both increase sedation. Use Caution/Monitor.

                • marijuana

                  clemastine and marijuana both increase sedation. Use Caution/Monitor.

                • melatonin

                  clemastine and melatonin both increase sedation. Use Caution/Monitor.

                • meperidine

                  clemastine and meperidine both increase sedation. Use Caution/Monitor.

                • meprobamate

                  clemastine and meprobamate both increase sedation. Use Caution/Monitor.

                • metaproterenol

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

                • metaxalone

                  clemastine and metaxalone both increase sedation. Use Caution/Monitor.

                • methadone

                  clemastine and methadone both increase sedation. Use Caution/Monitor.

                • methamphetamine

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

                • methocarbamol

                  clemastine and methocarbamol both increase sedation. Use Caution/Monitor.

                • methylenedioxymethamphetamine

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

                • midazolam

                  clemastine and midazolam both increase sedation. Use Caution/Monitor.

                • midazolam intranasal

                  clemastine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.

                  midazolam intranasal, clemastine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

                • midodrine

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

                • mirtazapine

                  clemastine and mirtazapine both increase sedation. Use Caution/Monitor.

                • modafinil

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

                • morphine

                  clemastine and morphine both increase sedation. Use Caution/Monitor.

                • motherwort

                  clemastine and motherwort both increase sedation. Use Caution/Monitor.

                • moxonidine

                  clemastine and moxonidine both increase sedation. Use Caution/Monitor.

                • nabilone

                  clemastine and nabilone both increase sedation. Use Caution/Monitor.

                • nalbuphine

                  clemastine and nalbuphine both increase sedation. Use Caution/Monitor.

                • norepinephrine

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

                • nortriptyline

                  clemastine and nortriptyline both increase sedation. Use Caution/Monitor.

                • olanzapine

                  clemastine and olanzapine both increase sedation. Use Caution/Monitor.

                • opium tincture

                  clemastine and opium tincture both increase sedation. Use Caution/Monitor.

                • orphenadrine

                  clemastine and orphenadrine both increase sedation. Use Caution/Monitor.

                • oxazepam

                  clemastine and oxazepam both increase sedation. Use Caution/Monitor.

                • oxycodone

                  clemastine and oxycodone both increase sedation. Use Caution/Monitor.

                • oxymorphone

                  clemastine and oxymorphone both increase sedation. Use Caution/Monitor.

                • paliperidone

                  clemastine and paliperidone both increase sedation. Use Caution/Monitor.

                • papaveretum

                  clemastine and papaveretum both increase sedation. Use Caution/Monitor.

                • papaverine

                  clemastine and papaverine both increase sedation. Use Caution/Monitor.

                • passion flower

                  passion flower increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • pentazocine

                  clemastine and pentazocine both increase sedation. Use Caution/Monitor.

                • pentobarbital

                  clemastine and pentobarbital both increase sedation. Use Caution/Monitor.

                • perphenazine

                  clemastine and perphenazine both increase sedation. Use Caution/Monitor.

                • phendimetrazine

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

                • phenelzine

                  phenelzine increases effects of clemastine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Coadministration of phenelzine and antihistamines may result in additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

                • phenobarbital

                  clemastine and phenobarbital both increase sedation. Use Caution/Monitor.

                • phentermine

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

                • phenylephrine

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

                • phenylephrine PO

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

                • pholcodine

                  clemastine and pholcodine both increase sedation. Use Caution/Monitor.

                • pimozide

                  clemastine and pimozide both increase sedation. Use Caution/Monitor.

                • pirbuterol

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

                • pregabalin

                  pregabalin, clemastine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

                • primidone

                  clemastine and primidone both increase sedation. Use Caution/Monitor.

                • prochlorperazine

                  clemastine and prochlorperazine both increase sedation. Use Caution/Monitor.

                • promethazine

                  clemastine and promethazine both increase sedation. Use Caution/Monitor.

                • propofol

                  propofol and clemastine both increase sedation. Use Caution/Monitor.

                • propylhexedrine

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

                • protriptyline

                  clemastine and protriptyline both increase sedation. Use Caution/Monitor.

                • quazepam

                  clemastine and quazepam both increase sedation. Use Caution/Monitor.

                • quetiapine

                  clemastine and quetiapine both increase sedation. Use Caution/Monitor.

                • ramelteon

                  clemastine and ramelteon both increase sedation. Use Caution/Monitor.

                • risperidone

                  clemastine and risperidone both increase sedation. Use Caution/Monitor.

                • salmeterol

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

                • scullcap

                  clemastine and scullcap both increase sedation. Use Caution/Monitor.

                • secobarbital

                  clemastine and secobarbital both increase sedation. Use Caution/Monitor.

                • sevoflurane

                  sevoflurane and clemastine both increase sedation. Use Caution/Monitor.

                • shepherd's purse

                  clemastine and shepherd's purse both increase sedation. Use Caution/Monitor.

                • stiripentol

                  stiripentol, clemastine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

                • sufentanil

                  clemastine and sufentanil both increase sedation. Use Caution/Monitor.

                • tapentadol

                  clemastine and tapentadol both increase sedation. Use Caution/Monitor.

                • tazemetostat

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

                • temazepam

                  clemastine and temazepam both increase sedation. Use Caution/Monitor.

                • terbutaline

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

                • thioridazine

                  clemastine and thioridazine both increase sedation. Use Caution/Monitor.

                • thiothixene

                  clemastine and thiothixene both increase sedation. Use Caution/Monitor.

                • tinidazole

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

                • topiramate

                  clemastine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

                • tramadol

                  clemastine and tramadol both increase sedation. Use Caution/Monitor.

                • trazodone

                  clemastine and trazodone both increase sedation. Use Caution/Monitor.

                • triazolam

                  clemastine and triazolam both increase sedation. Use Caution/Monitor.

                • triclofos

                  clemastine and triclofos both increase sedation. Use Caution/Monitor.

                • trifluoperazine

                  clemastine and trifluoperazine both increase sedation. Use Caution/Monitor.

                • trimipramine

                  clemastine and trimipramine both increase sedation. Use Caution/Monitor.

                • triprolidine

                  clemastine and triprolidine both increase sedation. Use Caution/Monitor.

                • valerian

                  valerian increases effects of clemastine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

                • xylometazoline

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

                • yohimbine

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

                • ziconotide

                  clemastine and ziconotide both increase sedation. Use Caution/Monitor.

                • ziprasidone

                  clemastine and ziprasidone both increase sedation. Use Caution/Monitor.

                • zotepine

                  clemastine and zotepine both increase sedation. Use Caution/Monitor.

                Minor (7)

                • ashwagandha

                  ashwagandha increases effects of clemastine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.

                • brimonidine

                  brimonidine increases effects of clemastine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

                • eucalyptus

                  clemastine and eucalyptus both increase sedation. Minor/Significance Unknown.

                • nettle

                  nettle increases effects of clemastine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.

                • ruxolitinib

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

                • sage

                  clemastine and sage both increase sedation. Minor/Significance Unknown.

                • Siberian ginseng

                  Siberian ginseng increases effects of clemastine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.

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                Adverse Effects

                Varies in incidence & severity with the individual drug; also individual patients vary in susceptibility

                Frequency Not Defined

                CNS depression

                Drowsiness

                Sedation ranging from mild drowsiness to deep sleep (most frequent)

                Dizziness

                Lassitude

                Disturbed coordination

                Muscular weakness

                Restlessness, insomnia, tremors, euphoria, nervousness, delirium, palpitation, seizures is less common

                Epigastric distress

                Anorexia

                Nausea

                Vomiting

                Diarrhea

                Constipation

                Cholestasis, hepatitis, hepatic failure, hepatic function abnormality, jaundice is rare

                Eczema, pruritus, inflammation, papular rash, erythema on exposed skin may occur with topical formulation

                Tachycardia, palpitation ECG changes (eg, widened QRS) Arrhythmias (eg, extrasystole, heart block)

                Hypotension

                Hypertension

                Dizziness, sedation, and hypotension may occur in geriatric patients

                Dryness of mouth, nose, and throat

                Dysuria

                Urinary retention

                Impotence

                Vertigo

                Visual disturbances

                Blurred vision

                Diplopia; tinnitus

                Acute labyrinthitis

                Insomnia

                Tremors

                Nervousness

                Irritability

                Facial dyskinesia

                Tightness of the chest

                Thickening of bronchial secretions

                Wheezing

                Nasal stuffiness

                Sweating

                Chills

                Early menses

                Toxic psychosis

                Headache

                Faintness

                Paresthesia

                Agranulocytosis

                Hemolytic anemia

                Leukopenia

                Thrombocytopenia

                Pancytopenia

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                Warnings

                Contraindications

                Documented hypersensitivity

                Lower respiratory disease, eg, asthma (controversial)

                Preemies & neonates

                Nursing women

                Caution

                Caution in narrow angle glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, or bladder neck obstruction

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                Pregnancy & Lactation

                Pregnancy Category: B

                Lactation: enters breast milk/not recommended

                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

                Histamine H1-receptor antagonist in blood vessels, respiratory tract, and gastrointestinal tract

                Pharmacokinetics

                Onset: 5-7 hr

                Duration: 8-12 hr

                Peak Plasma Time: 2-5 hr

                Vd: 800 L

                Metabolism: Hepatic

                Bioavailability: ~40%

                Half-life elimination: 21 hr

                Excretion: Urine

                Sedation: Low to moderate

                Antihistamine activity: Low to moderate

                Anticholinergic activity: High

                Antiemetic effects: Low to moderate

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                Images

                BRAND FORM. UNIT PRICE PILL IMAGE
                clemastine oral
                -
                		2.68 mg tablet

                Copyright © 2010 First DataBank, Inc.

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                Patient Handout

                Patient Education
                clemastine oral

                CLEMASTINE - ORAL

                (KLEM-ast-een)

                COMMON BRAND NAME(S): Tavist

                USES: Clemastine is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, watery eyes, itchy eyes/nose/throat/skin, cough, runny nose, and sneezing. This medication works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. By blocking another natural substance made by your body (acetylcholine), it helps dry up some body fluids to relieve symptoms such as watery eyes and runny nose.Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).

                HOW TO USE: If you are taking the over-the-counter product, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed.Take the tablet or liquid form by mouth with or without food. Follow the directions for dosing on the label, or take as directed by your doctor. This medication may be taken with food or milk if stomach upset occurs.If you are using the liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.Your dosage is based on your age, medical condition, and response to therapy. Do not increase your dose or take this medication more often than recommended by your doctor or the package instructions without your doctor's approval. Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.If your condition persists or worsens, or if you think you may have a serious medical problem, seek immediate medical attention.

                SIDE EFFECTS: Drowsiness, dizziness, headache, constipation, stomach upset, blurred vision, trouble walking/clumsiness, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. Clemastine can dry up and thicken mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, drink plenty of fluids unless otherwise directed by your doctor.If your doctor has prescribed this medication, remember that 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.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (e.g., hallucinations, irritability, nervousness, confusion), ringing in the ears, trouble urinating, easy bruising/bleeding, fast/irregular heartbeat, seizure.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 clemastine, tell your doctor or pharmacist if you are allergic to it; 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: breathing problems (e.g., asthma, emphysema), a certain eye problem (glaucoma), heart problems, high blood pressure, liver disease, seizures, stomach problems (e.g., ulcers, blockage), overactive thyroid (hyperthyroidism), urination problems (e.g., trouble urinating due to enlarged prostate, urinary retention).This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).To minimize dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.Liquid preparations of this product may contain sugar and/or alcohol. Caution is advised if you have diabetes, alcohol dependence, or liver disease. Ask your doctor or pharmacist about the safe use of this product.Older adults may be more sensitive to the side effects of this drug, especially drowsiness, constipation, problems urinating, or confusion. Drowsiness and confusion can increase the risk of falling.Children may be more sensitive to the effects of antihistamines. In young children, this medication may cause agitation/excitement instead of drowsiness.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This drug passes into breast milk and may have undesirable effects on a nursing infant. 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: antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray).Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or other antihistamines (such as cetirizine, diphenhydramine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

                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: large pupils, flushing, fever, hallucinations, weakness, shaking (tremor), muscle twitching, loss of consciousness, seizures. In children, excitement may occur first, and may be followed by loss of coordination, drowsiness, loss of consciousness, seizures.

                NOTES: If your doctor has prescribed this medication, do not share it with others.Keep all regular medical and laboratory appointments.Do not take for several days before allergy testing because test results can be affected.

                MISSED DOSE: If you are taking this medication on a regular schedule and miss a dose, take it as soon as you remember. If it is near the time of your next dose, 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. Do not store in the bathroom. Do not freeze liquid forms of this medication. 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 August 2021. Copyright(c) 2021 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.

                Create Your List of Plans

                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.

                View explanations for tiers and restrictions
                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.
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