phenylephrine/guaifenesin (OTC)

Brand and Other Names:Sudafed PE Non-Drying Sinus Caplets

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

phenylephrine/guaifenesin

caplet

  • 5mg/200mg
  • 10mg/400mg

tablet

  • 5mg/200mg
  • 10mg/400mg

liquid

  • (7.5mg/100mg)/5mL
  • (2.5mg/100mg)/5mL
  • (10mg/200mg)/5mL
  • (5mg/100mg)/5mL

syrup

  • (5mg/200mg)/5mL
  • (2.5mg/50mg)/5mL

Congestion with Mucus

2 tabs/caps [(5mg/200mg)/tab] PO q4hr; not to exceed 12 tabs/24hr

Administration

Give with food if GI upset occurs

Dosage Forms & Strengths

phenylephrine/guaifenesin

caplet

  • 5mg/200mg
  • 10mg/400mg

tablet

  • 5mg/200mg
  • 10mg/400mg

liquid

  • (7.5mg/100mg)/5mL
  • (2.5mg/100mg)/5mL
  • (10mg/200mg)/5mL
  • (5mg/100mg)/5mL

syrup

  • (5mg/200mg)/5mL
  • (2.5mg/50mg)/5mL

Congestion with Mucus

<6 years

  • Safety and efficacy not established

6-12 years

  • 10 mL [(2.5mg/50mg)/5mL] PO q4hr PRN; not to exceed 60 mL/24hr
  • 10 mL [(2.5mg/100mg)/5mL] PO q4hr PRN; not to exceed 60 mL/24hr

>12 years

  • 2 tabs/caps [(5mg/200mg)/tab] PO q4hr; not to exceed 12 tabs/24hr
Next:

Interactions

Interaction Checker

and phenylephrine/guaifenesin

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      Serious - Use Alternative

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            Contraindicated (7)

            • iobenguane I 123

              phenylephrine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.

            • isocarboxazid

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

            • linezolid

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

            • phenelzine

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

            • procarbazine

              procarbazine increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

            • selegiline transdermal

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

            • tranylcypromine

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

            Serious - Use Alternative (27)

            • amitriptyline

              amitriptyline, phenylephrine. 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, phenylephrine. 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.

            • cabergoline

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

            • clomipramine

              clomipramine, phenylephrine. 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 phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

              desflurane increases levels of phenylephrine by decreasing metabolism. Contraindicated.

            • desipramine

              desipramine, phenylephrine. 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, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • dihydroergotamine intranasal

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

            • doxapram

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

            • doxepin

              doxepin, phenylephrine. 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, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • ergotamine

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

            • ether

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

            • etomidate

              etomidate increases levels of phenylephrine by decreasing metabolism. Contraindicated.

            • imipramine

              imipramine, phenylephrine. 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.

            • isoflurane

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

            • lofepramine

              lofepramine, phenylephrine. 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.

            • maprotiline

              maprotiline, phenylephrine. 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 phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

            • methylergonovine

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

            • nortriptyline

              nortriptyline, phenylephrine. 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.

            • propofol

              propofol increases levels of phenylephrine by decreasing metabolism. Contraindicated.

            • protriptyline

              protriptyline, phenylephrine. 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.

            • sevoflurane

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

              sevoflurane increases levels of phenylephrine by decreasing metabolism. Contraindicated.

            • trazodone

              trazodone, phenylephrine. 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, phenylephrine. 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.

            • yohimbe

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

            Monitor Closely (169)

            • albuterol

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

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

            • alfentanil

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

            • alprazolam

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

            • amitriptyline

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

            • amobarbital

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

            • amoxapine

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

            • arformoterol

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

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

            • aripiprazole

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

            • armodafinil

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

            • atomoxetine

              atomoxetine, phenylephrine. Other (see comment). Use Caution/Monitor. Comment: Due to the potential for increases in blood pressure and heart rate, atomoxetine should be used cautiously with vasopressors such as phenylephrine.

            • azelastine

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

            • belladonna and opium

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

            • benperidol

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

            • benzphetamine

              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.

            • bromocriptine

              bromocriptine, phenylephrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Hypertension, V tach.

            • brompheniramine

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

            • buprenorphine buccal

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

            • butabarbital

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

            • butalbital

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

            • butorphanol

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

            • caffeine

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

            • carbinoxamine

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

            • chloral hydrate

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

            • chlordiazepoxide

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

            • chlorpheniramine

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

            • chlorpromazine

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

              chlorpromazine, phenylephrine. 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.

            • cinnarizine

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

            • clemastine

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

            • clomipramine

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

            • clonazepam

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

            • clorazepate

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

            • clozapine

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

            • codeine

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

            • cyclizine

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

            • cyproheptadine

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

            • desipramine

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

            • dexchlorpheniramine

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

            • dexfenfluramine

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

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

            • dexmedetomidine

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

            • dexmethylphenidate

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

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

            • dextroamphetamine

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

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

            • dextromoramide

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

            • diamorphine

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

            • diethylpropion

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

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

            • difenoxin hcl

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

            • dimenhydrinate

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

            • diphenhydramine

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

            • diphenoxylate hcl

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

            • dipipanone

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

            • dobutamine

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

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

            • dopamine

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

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

            • dopexamine

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

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

            • doxepin

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

            • droperidol

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

            • droxidopa

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

            • ephedrine

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

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

              ephedrine, phenylephrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor.

            • epinephrine

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

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

            • epinephrine inhaled

              phenylephrine, 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 phenylephrine both decrease sedation. Use Caution/Monitor.

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

            • estazolam

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

            • ethanol

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

            • fenfluramine

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

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

            • fluphenazine

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

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

            • formoterol

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

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

            • haloperidol

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

            • hydralazine

              hydralazine, phenylephrine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.

            • hydromorphone

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

            • hydroxyzine

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

            • iloperidone

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

            • imipramine

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

            • indacaterol, inhaled

              phenylephrine increases effects of indacaterol, inhaled by Other (see comment). Use Caution/Monitor. Comment: If additional adrenergic drugs are to be administered by any route, they should be used with caution because the sympathetic effects of indacaterol may be potentiated.

            • insulin degludec

              phenylephrine decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

            • insulin degludec/insulin aspart

              phenylephrine decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

            • insulin inhaled

              phenylephrine decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

            • isoproterenol

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

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

            • ketotifen, ophthalmic

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

            • levalbuterol

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

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

            • levorphanol

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

            • lisdexamfetamine

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

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

            • lofepramine

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

            • lofexidine

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

            • loprazolam

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

            • lorazepam

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

            • lormetazepam

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

            • loxapine

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

            • loxapine inhaled

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

            • maprotiline

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

            • marijuana

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

            • melatonin

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

            • meperidine

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

            • meprobamate

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

            • metaproterenol

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

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

            • methadone

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

            • methamphetamine

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

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

            • methyldopa

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

            • methylenedioxymethamphetamine

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

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

            • midazolam

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

            • midodrine

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

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

            • mirtazapine

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

            • modafinil

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

            • morphine

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

            • motherwort

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

            • moxonidine

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

            • nabilone

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

            • nadolol

              nadolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).

            • nalbuphine

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

            • norepinephrine

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

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

            • nortriptyline

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

            • olanzapine

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

            • olodaterol inhaled

              phenylephrine and olodaterol inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Caution with coadministration of adrenergic drugs by any route because of additive sympathetic effects

            • opium tincture

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

            • oxazepam

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

            • oxycodone

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

            • oxymetazoline topical

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

            • oxymorphone

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

            • oxytocin

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

            • paliperidone

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

            • papaveretum

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

            • pentazocine

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

            • pentobarbital

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

            • perphenazine

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

              perphenazine, phenylephrine. 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

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

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

            • phenobarbital

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

            • phentermine

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

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

            • pholcodine

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

            • pimozide

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

            • pindolol

              pindolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).

            • pirbuterol

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

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

            • primidone

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

            • prochlorperazine

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

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

              promethazine, phenylephrine. 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.

            • propofol

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

            • propranolol

              propranolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).

            • propylhexedrine

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

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

            • protriptyline

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

            • pseudoephedrine

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

            • quazepam

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

            • quetiapine

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

            • rasagiline

              rasagiline increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.

            • risperidone

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

            • safinamide

              phenylephrine and safinamide both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Monitor patients for hypertension if safinamide is prescribed concomitantly with prescription or nonprescription sympathomimetics, including nasal, oral, or ophthalmic decongestants and cold remedies.

            • salmeterol

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

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

            • scullcap

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

            • secobarbital

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

            • selegiline

              selegiline increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.

            • serdexmethylphenidate/dexmethylphenidate

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

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

            • shepherd's purse

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

            • solriamfetol

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

            • sufentanil

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

            • tapentadol

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

            • temazepam

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

            • terbutaline

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

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

            • thioridazine

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

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

            • timolol

              timolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).

            • topiramate

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

            • tramadol

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

            • trazodone

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

            • triazolam

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

            • triclofos

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

            • trifluoperazine

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

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

            • triprolidine

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

            • xylometazoline

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

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

            • yohimbine

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

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

            • ziconotide

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

            • ziprasidone

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

            Minor (12)

            • alfuzosin

              alfuzosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • asenapine

              asenapine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • desmopressin

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

            • doxazosin

              doxazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • eucalyptus

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

            • moxisylyte

              moxisylyte, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • phenoxybenzamine

              phenoxybenzamine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • phentolamine

              phentolamine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • prazosin

              prazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • sage

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

            • silodosin

              silodosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • terazosin

              terazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

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            Adverse Effects

            Frequency Not Defined

            Headache

            Dizziness

            Anxiety

            Nervousness

            Restlessness

            Tremor

            Weakness

            Insomnia

            Hallucinations

            Convulsions

            CNS depression

            Tachycardia

            Palpitations

            Arrhythmias

            Cardiovascular collapse with hypotension

            Respiratory difficulty

            Nausea

            Dysuria

            Pallor

            Rash

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            Warnings

            Contraindications

            Hypersensitivity to either component

            Severe hypertension

            Severe cardiovascular disease

            Use within 14 days of MAO inhibitor

            Closed angle glaucoma

            Cautions

            Do not use as self-medication in chronic or persistent coughs

            Caution in cardiovascular disease, diabetes, increased intraocular pressure/glaucoma, BPH, thyroid dysfunction, or GU obstruction

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            Pregnancy & Lactation

            Pregnancy Category: C

            Lactation: small amounts of phenylephrine excreted in breast milk, caution advised

            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

            Phenylephrine: Strong alpha effects resulting in increased PVR and BP and decreased COand renal perfusion

            Guaifenesin: Reduces viscosity of secretions by increasing amount of respiratory tract fluid

            Half-Life

            Phenylephrine: 2-3 hr

            Guaifenesin: 1 hr

            Onset

            Phenylephrine: 10-15 min

            Guaifenesin: 30 min

            Duration

            Guaifenesin: 4-6 hr

            Phenylephrine: 15 min (IV); 1-2 hr (IM); 50 min (SC)

            Metabolism

            Phenylephrine: Extensively in intestinal wall, moderately in liver

            Guaifenesin: Liver

            Metabolites

            Penylephrine: M-hydroxymandelic acid (inactive)

            Guaifenesin: b-(2-methoxyphenoxy) lactic acid

            Excretion

            Phenylephrine: Urine (80-90%)

            Guaifenesin: Urine

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            Images

            No images available for this drug.
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            Patient Handout

            A Patient Handout is not currently available for this monograph.
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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.