Zyrtec-D (cetirizine HCl/pseudoephedrine HCl)

The manufacturer states that patients 12 years of age or older who have impaired renal function (e.g., creatinine clearance of 11-31 mL/minute) or hepatic impairment or who are undergoing hemodialysis (creatinine clearance of less than 7 mL/minute), should receive a cetirizine hydrochloride dosage of 5 mg daily. The manufacturer also states that children 6-11 years of age with impaired renal or hepatic function should use the lower recommended dosage (5 mg once daily). The manufacturer states that use of cetirizine hydrochloride in children younger than 6 years of age with impaired renal or hepatic function is not recommended because administration of doses smaller than 2.5 mg is difficult and not reliable, and pharmacokinetic data are lacking in this patient population.

When extended-release tablets of cetirizine hydrochloride in fixed combination with pseudoephedrine hydrochloride are used in patients 12 years of age or older who have impaired renal function (i.e., creatinine clearance of 11-31 mL/minute) or hepatic impairment or who are undergoing hemodialysis (creatinine clearance of less than 7 mL/minute), the recommended cetirizine hydrochloride dosage is 5 mg once daily.

Pseudoephedrine hydrochloride and sulfate are administered orally.

Pseudoephedrine hydrochloride 240-mg extended-release tablets should be administered orally once daily and swallowed whole with water; the extended-release tablets should not be divided, crushed, chewed, or dissolved. Patients should be advised that the tablet does not completely dissolve and may be passed in the stool.

Cetirizine is administered orally. Cetirizine oral solution (syrup) should be administered using the measuring device (i.e., cup) provided by the manufacturer. Cetirizine chewable tablets may be administered with or without water. Tablets containing cetirizine hydrochloride in fixed combination with pseudoephedrine hydrochloride should be swallowed intact and patients should be instructed not to break or chew such tablets.

The manufacturer states that the time of administration of cetirizine may be adjusted for individual patient requirements. Although food may decrease peak plasma concentrations of cetirizine and lengthen the time to achievement of peak plasma concentrations, the manufacturer states that cetirizine may be administered without regard to food because food does not affect the extent of absorption of the drug when administered as conventional or chewable tablets.

The oral bioavailability of cetirizine hydrochloride conventional tablets is comparable to that of the oral solution and to that of the chewable tablets (administered with or without water).

Because cetirizine is metabolized only minimally in the liver and is excreted mainly unchanged in urine, the drug may have a low potential for adverse drug interactions associated with metabolic enzyme systems.

Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

Mixed & Indirect Sympathomimetics; Oral Phenylephrine/Maois

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine).

CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Fatalities have occurred.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Concurrent use of monoamine oxidase inhibitors and sympathomimetics is contraindicated. The manufacturers of sympathomimetic agents recommend waiting 14 days after discontinuation of MAO inhibitors before initiating the sympathomimetic.

DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors. Linezolid is another antibacterial with monoamine oxidase inhibitor properties. Metaxalone is a weak inhibitor of MAO. Foods containing large amounts of tyramine have also been implicated in this interaction. Methylene blue, when administered intravenously, has been shown to reach sufficient concentrations to be a potent inhibitor of MAO-A. At recommended dosages, rasagiline, oral selegiline, and transdermal selegiline up to 6mg/day are selective for MAO-B; however, at higher dosages they have been shown to lose their selectivity. One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Sympathomimetics/Dihydroergotamine

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Concurrent use of dihydroergotamine and sympathomimetics may result in additive or synergistic effect on peripheral blood vessels.(1)

CLINICAL EFFECTS: Concurrent use of dihydroergotamine and sympathomimetics may result in increased blood pressure due to peripheral vasoconstriction.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Dihydroergotamine is contraindicated with sympathomimetics because the combination may result in additive or synergistic elevation of blood pressure.(1)

DISCUSSION: Significant elevation in blood pressure has been reported in patients treated with dihydroergotamine.(1) Sympathomimetics can be expected to have additional effects on blood pressure.

Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

Agents That Affect Catecholamines/Iobenguane I 123

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells.(1)

CLINICAL EFFECTS: Compounds that reduce catecholamine uptake or that deplete catecholamine stores may interfere with imaging completed with iobenguane.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Discuss the use of agents that affect catecholamines. Discontinue drugs that reduce catecholamine uptake or deplete catecholamine stores prior to imaging with iobenguane. Before imaging with iobenguane, discontinue agents that affect catecholamines for at least 5 biological half-lives, as clinically tolerated.(1)

DISCUSSION: Many agents may reduce catecholamine uptake or deplete catecholamine stores.(1) Examples include: - CNS stimulants or amphetamines (e.g. cocaine, methylphenidate, dextroamphetamine) - norepinephrine and dopamine reuptake inhibitors (e.g. phentermine) - norepinephrine and serotonin reuptake inhibitors (e.g. tramadol) - monoamine oxidase inhibitors (e.g. phenelzine, linezolid) - central monoamine depleting drugs (e.g. reserpine) - non-select beta adrenergic blocking drugs (e.g. labetalol) - alpha agonists or alpha/beta agonists (e.g. pseudoephedrine, phenylephrine, ephedrine, phenylpropanolamine, naphazoline) - tricyclic antidepressants or norepinephrine reuptake inhibitors (e.g. amitriptyline, bupropion, duloxetine, mirtazapine, venlafaxine) - botanicals that may inhibit reuptake of norepinephrine, serotonin or dopamine (e.g. ephedra, ma huang, St. John's Wort, yohimbine)

Agents That Affect Catecholamines/Iobenguane I 131

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells.(1)

CLINICAL EFFECTS: Compounds that reduce catecholamine uptake or that deplete catecholamine stores may impact the dosimetry calculations or effectiveness of iobenguane.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Discuss the use of agents that affect catecholamines. Discontinue drugs that reduce catecholamine uptake or deplete catecholamine stores for at least 5 half-lives before administration of either the dosimetry or a therapeutic dose of iobenguane. Do not administer these drugs until at least 7 days after each iobenguane dose.(1)

DISCUSSION: Many agents may reduce catecholamine uptake or deplete catecholamine stores.(1) Examples include: - CNS stimulants or amphetamines (e.g. cocaine, methylphenidate, dextroamphetamine) - norepinephrine and dopamine reuptake inhibitors (e.g. phentermine) - norepinephrine and serotonin reuptake inhibitors (e.g. tramadol) - monoamine oxidase inhibitors (e.g. phenelzine, linezolid) - central monoamine depleting drugs (e.g. reserpine) - non-select beta adrenergic blocking drugs (e.g. labetalol) - alpha agonists or alpha/beta agonists (e.g. pseudoephedrine, phenylephrine, ephedrine, phenylpropanolamine, naphazoline) - tricyclic antidepressants or norepinephrine reuptake inhibitors (e.g. amitriptyline, bupropion, duloxetine, mirtazapine, venlafaxine) - botanicals that may inhibit reuptake of norepinephrine, serotonin or dopamine (e.g. ephedra, ma huang, St. John's Wort, yohimbine) - calcium channel blockers

Agents That Affect Iodide/Radioactive Iodide

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1)

CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1)

PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less.

PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(2) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(3)

DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1)

Agents That Affect Iodide/Sodium Iodide I 131

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1,2)

CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1,2)

PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less.

PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1,2) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(3) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(4)

DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1,2)

Mixed & Indirect Sympathomimet; Oral Phenylephrine/Slt Maois

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine).

CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Fatalities have occurred with combinations of sympathomimetics and MAO-A inhibitors.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Concurrent use of MAO-A inhibitors and sympathomimetics is contraindicated. The manufacturers of sympathomimetic agents recommend waiting 14 days after discontinuation of MAO inhibitors before initiating the sympathomimetic. Patients receiving indirect acting sympathomimetics should not receive linezolid unless they are monitored for potential increases in blood pressure. Initial dosages of dopamine should be reduced. At recommended dosages, oral selegiline and transdermal selegiline up to 6mg/day are selective for MAO-B; however, at higher dosages they have been shown to lose their selectivity. Patients receiving higher dosages of selegiline should be considered susceptive to this interaction.

DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors. Foods containing large amounts of tyramine have also been implicated in this interaction. A significant pressor response was observed in normal subjects receiving linezolid and tyramine doses of more than 100 mg. Administration of linezolid (600 mg BID for 3 days) with pseudoephedrine (60 mg q 4 hours for 2 doses) increased blood pressure by 32 mmHg. Administration of linezolid (600 mg BID for 3 days) with phenylpropanolamine (25 mg q 4 hours for 2 doses) increased blood pressure by 38 mmHg. One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Mixed & Indirect Sympathomimet;Oral Phenylephrine/Rasagiline

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine).

CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Hypertensive crisis has been reported in patients taking recommended doses of rasagiline with sympathomimetic agents.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: At recommended dosages, rasagiline is selective for MAO-B; however, at higher dosages it has been shown to lose its selectivity. Patients receiving higher dosages of rasagiline should be considered susceptive to this interaction. Concurrent use should be approached with caution.

DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors.

Sympathomimetics/Ergot Alkaloids

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Concurrent use of ergot alkaloids and sympathomimetics may result in additive or synergistic effect on peripheral blood vessels.

CLINICAL EFFECTS: Concurrent use of ergot alkaloids and sympathomimetics may result in increased blood pressure due to peripheral vasoconstriction.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: When possible, avoid the concurrent use of ergot alkaloids and sympathomimetics. If concurrent use is warranted, monitor blood pressure and for signs of vasoconstriction. Decreasing the dose of one or both drugs may be necessary.

DISCUSSION: There have been reports of severe vasoconstriction resulting in gangrene in patients receiving intravenous ergonovine with dopamine or norepinephrine.

Moderate Interaction: Assess the risk to the patient and take action as needed.

Sympathomimetics (DIRECT, MIXED-ACTING)/Guanethidine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Direct or mixed-acting sympathomimetics may inhibit uptake of guanethidine at the adrenergic neuron.

CLINICAL EFFECTS: Decreased antihypertensive effectiveness. Effects may be seen for several days after discontinuation of the direct or mixed-acting sympathomimetic.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Avoid concomitant administration of these drugs. If both drugs are administered, adjust the guanethidine dose as needed based on blood pressure.

DISCUSSION: Documentation supports routine monitoring of this interaction. It should be noted that this interaction can occur quickly.

Sympathomimetics (DIRECT, MIXED-ACTING)/Methyldopa

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Unknown.

CLINICAL EFFECTS: The pressor response to sympathomimetics may be increased.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Start with low doses of sympathomimetics and monitor blood pressure of patients during concurrent administration of sympathomimetics and methyldopa.

DISCUSSION: The pressor response to sympathomimetics has been reported to be increased during methyldopa administration. In addition to increased duration of pressor response, severe hypertension has been reported.

Sympathomimetics/Rauwolfia Alkaloids

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Reserpine depletes catecholamine stores within the peripheral vascular adrenergic nerve endings, thus indirect acting sympathomimetics are unable to trigger the release of catecholamines. The reserpine-induced catecholamine release increases sensitivity to the effects of direct acting sympathomimetics.

CLINICAL EFFECTS: Increased effects of direct acting sympathomimetics. Decreased effects of indirect acting sympathomimetics. Mixed acting sympathomimetics will show effects based on the predominance of either direct or indirect activity.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If these agents are administered concurrently, monitor blood pressure. The dose of the sympathomimetic may need to be adjusted.

DISCUSSION: This interaction has been well documented in animal studies and human case reports have confirmed the interaction. Reserpine has been shown to decrease the response to epinephrine administered for hypotension. Reserpine has also been shown to decrease the effectiveness of ophthalmic epinephrine, a direct acting sympathomimetic. Ophthalmic phenylephrine has been shown to decrease the hypotensive effects of reserpine.

There is no enhanced messaging for this drug.

• Severe coronary artery disease
• Severe uncontrolled hypertension
• Urinary retention

• Angle-closure glaucoma
• Benign prostatic hyperplasia
• Chronic kidney disease stage 4 (severe) GFR 15-29 ml/min
• Chronic kidney disease stage 5 (failure) GFr<15 ml/min
• Diabetes mellitus
• Disease of liver
• Hypertension
• Hyperthyroidism
• Pheochromocytoma

• Kidney disease with reduction in glomerular filtration rate (GFr)
• Severe hepatic disease

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Rare or Very Rare

• Abnormal hepatic function tests
• Acute generalized exanthematous pustulosis
• Acute generalized exanthematous pustulosis
• Anaphylaxis
• Bronchospastic pulmonary disease
• Cardiac arrhythmia
• Cholestasis
• Dehydration
• Dyspnea
• Edema
• Glomerulonephritis
• Hallucinations
• Hearing loss
• Hemolytic anemia
• Hepatitis
• Hypertension
• Ischemic colitis
• Palpitations
• Posterior reversible encephalopathy syndrome
• Reversible cerebral vasoconstriction syndrome
• Seizure disorder
• Seizure disorder
• Thrombocytopenic disorder
• Tongue swelling
• Tonic clonic seizure
• Vomiting

More Frequent

• Drowsy
• Dry nose
• Dry throat
• Headache disorder
• Insomnia
• Xerostomia

Less Frequent

• Acute abdominal pain
• Agitation
• Anorexia
• Diarrhea
• Dizziness
• Drowsy
• Dysuria
• Epistaxis
• Fatigue
• General weakness
• Insomnia
• Nausea
• Nausea
• Nervousness
• Pallor
• Pharyngitis
• Tachycardia
• Tremor

Rare or Very Rare

• Abdominal pain with cramps
• Acne vulgaris
• Acute cognitive impairment
• Aggressive behavior
• Alopecia
• Anorexia
• Anticholinergic toxicity
• Blurred vision
• Cardiac arrhythmia
• Chest tightness
• Constipation
• Cramps in legs
• Dizziness
• Dysgeusia
• Dyskinesia
• Dyspepsia
• Dyspepsia
• Dysuria
• Eructation
• Euphoria
• Excitement
• Excitement
• Flatulence
• Gastritis
• Hallucinations
• Headache disorder
• Hemorrhoids
• Hyperhidrosis
• Hyperhidrosis
• Increased appetite
• Memory impairment
• Nervousness
• Nightmares
• Palpitations
• Parosmia
• Skin photosensitivity
• Skin rash
• Stomatitis
• Symptoms of anxiety
• Syncope
• Syncope
• Tachycardia
• Tinnitus
• Tongue discoloration
• Tremor
• Unsteady gait
• Urinary retention
• Visual changes
• Vomiting
• Weight gain

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Reproduction studies in mice, rats, and rabbits using oral cetirizine hydrochloride dosages up to 96, 225, and 135 mg/kg daily, respectively (approximately 40, 180, and 220 times, respectively, the maximum recommended daily oral dosage in adults on a mg/m2 basis), have not revealed evidence of teratogenicity. Because there are no adequate and controlled studies to date using cetirizine in pregnant women and animal studies are not always predictive of human response, cetirizine hydrochloride should be used during pregnancy only when clearly needed.

Cetirizine hydrochloride in combination with pseudoephedrine has been shown to increase the number of fetal skeletal malformations (rib distortions) and variants (unossified sternebrae) in rats when given orally in a fixed-combination ratio at a dosage of 6/154 mg/kg (approximately 5 times the maximum recommended adult dosage on a mg/m2 basis). These effects were not observed at a dosage of 1.6/38 mg/kg (approximately the maximum recommended adult dosage on a mg/m2 basis). Reproduction studies in rabbits using cetirizine hydrochloride and pseudoephedrine hydrochloride in a fixed-combination ratio at a dosage of up to 6/154 mg/kg (approximately 10 times the maximum recommended adult dosage on a mg/m2 basis) have not revealed evidence of harm to the fetus. There are no adequate and controlled studies to date using cetirizine hydrochloride and pseudoephedrine hydrochloride in pregnant women, and the fixed combination should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.

In lactating beagles, about 3% of a cetirizine dose was distributed in milk. In mice, cetirizine caused retarded pup weight gain during lactation when dams were receiving a cetirizine hydrochloride dosage of 96 mg/kg daily (about 40 times the maximum recommended daily dosage in adults on a mg/m2 basis). In rats, cetirizine hydrochloride and pseudoephedrine hydrochloride caused retarded pup weight gain and decreased viability during lactation when administered orally to dams in fixed combination at a dosage of 6/154 mg/kg (approximately 5 times the maximum recommended adult dosage on a mg/m2 basis) but not when administered at a dosage of 1.6/38 mg/kg (approximately the maximum recommended adult dosage on a mg/m2 basis). Cetirizine is distributed into human milk. Pseudoephedrine also distributes into human milk. Therefore, use of cetirizine hydrochloride alone or in combination with pseudoephedrine hydrochloride in nursing women is not recommended.

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