Usage
Cetirizine + Pseudoephedrine is prescribed for the temporary relief of symptoms associated with seasonal or perennial allergic rhinitis, such as nasal and sinus congestion, sneezing, runny nose, itching, and watery eyes. It combines the effects of an antihistamine (cetirizine) and a decongestant (pseudoephedrine).
- Pharmacological Classification: This drug is a combination product belonging to the following classifications:
- Antihistamine (Cetirizine): H1 receptor antagonist
- Decongestant (Pseudoephedrine): Alpha-adrenergic agonist.
- Mechanism of Action: Cetirizine works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Pseudoephedrine works by constricting blood vessels in the nasal passages, which reduces swelling and congestion.
Alternate Names
This combination medication may also be known as:
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Cetirizine-Pseudoephedrine
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Cetirizine Dihydrochloride and Pseudoephedrine Hydrochloride Extended-Release Tablets
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Brand Names: Zyrtec-D, REACTINE COMPLETE, All Day Allergy-D, Allergy D-12, Allergy Relief Nasal Decongestant, Goodsense Cetirizine D-12 Hour, KS Aller-Tec D-12, Wal-Zyr D, Leader Allergy Relief D
How It Works
- Pharmacodynamics: Cetirizine exerts its effect by competitively inhibiting the binding of histamine to H1 receptors. Pseudoephedrine acts as an alpha-adrenergic agonist, causing vasoconstriction in the nasal mucosa, which reduces nasal congestion.
- Pharmacokinetics:
- Absorption: Both cetirizine and pseudoephedrine are rapidly absorbed after oral administration. Food may slightly delay the absorption of cetirizine but doesn’t affect its overall bioavailability.
- Metabolism: Cetirizine undergoes minimal hepatic metabolism. Pseudoephedrine is partially metabolized in the liver by N-demethylation to norpseudoephedrine.
- Elimination: Cetirizine is primarily excreted unchanged in the urine. Pseudoephedrine is also mainly eliminated through renal excretion, both as the parent compound and its metabolite. The elimination half-life of cetirizine is around 8 hours, while pseudoephedrine’s half-life is 3-6 hours in acidic urine and 9-16 hours in alkaline urine.
- Mode of Action (Cellular/Molecular): Cetirizine selectively binds to peripheral H1 receptors, preventing histamine from binding and triggering the cascade of events leading to allergic symptoms. Pseudoephedrine stimulates alpha-adrenergic receptors on vascular smooth muscle in the nasal mucosa, resulting in vasoconstriction.
- Receptor Binding/Enzyme Inhibition: Cetirizine acts as an H1 receptor antagonist. Pseudoephedrine is an alpha-adrenergic receptor agonist.
- Elimination Pathways: Primarily renal excretion for both cetirizine and pseudoephedrine.
Dosage
Standard Dosage
Adults (12 years and older): One extended-release tablet every 12 hours. Do not exceed two tablets in 24 hours.
Children (4 to 11 years): The combination of cetirizine and pseudoephedrine is generally not recommended. Consult a physician for dosing instructions for individual components if necessary. Children younger than 4 years of age should not receive the combination medication.
Special Cases:
- Elderly Patients (65 years and older): Start with one tablet once daily; may increase to one tablet every 12 hours if needed and tolerated. Consider renal function.
- Patients with Renal Impairment: Dosage adjustment is necessary. For moderate to severe renal impairment (creatinine clearance < 30 mL/min), one tablet daily is recommended.
- Patients with Hepatic Dysfunction: Dosage adjustment is necessary. For moderate to severe hepatic impairment, one tablet daily is recommended.
- Patients with Comorbid Conditions: Use caution in patients with cardiovascular disease, diabetes, hyperthyroidism, glaucoma, or prostatic hypertrophy. Individualized dosing may be necessary.
Clinical Use Cases
Cetirizine + Pseudoephedrine is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, or the ICU. Its primary indication is for the relief of allergy and cold symptoms in an outpatient setting. It is not typically indicated for emergency situations such as status epilepticus or cardiac arrest.
Dosage Adjustments
Dosage adjustments are essential for elderly patients, patients with renal or hepatic impairment, and those with certain comorbid conditions like cardiovascular disease or diabetes.
Side Effects
Common Side Effects:
- Dry mouth
- Drowsiness or unusual sleepiness
- Fatigue
- Dizziness
- Headache
- Insomnia
- Trouble concentrating
- Nausea, stomach pain, constipation
- Nervousness
Rare but Serious Side Effects:
- Allergic reactions (hives, difficulty breathing, swelling)
- Cardiac arrhythmias (fast, pounding, or uneven heartbeat)
- Hypertension (severe headache, buzzing in the ears, chest pain)
- Tremors, severe restlessness, hyperactivity
- Difficulty urinating
- Confusion, hallucinations, psychosis
- Seizures, stroke, myocardial infarction
Long-Term Effects:
Prolonged use can lead to rebound congestion with pseudoephedrine.
Adverse Drug Reactions (ADR):
See “Rare but Serious Side Effects.”
Contraindications
- Hypersensitivity to cetirizine, pseudoephedrine, or hydroxyzine
- Narrow-angle glaucoma
- Urinary retention
- Severe hypertension or coronary artery disease
- Concurrent or recent (within 14 days) use of monoamine oxidase inhibitors (MAOIs)
- Uncontrolled hyperthyroidism
- Severe arrhythmia
Drug Interactions
- CNS Depressants: Alcohol and other medications that cause drowsiness may enhance the sedative effects of cetirizine.
- MAO Inhibitors: Concurrent use is contraindicated and can lead to a hypertensive crisis.
- Tricyclic Antidepressants: May enhance the effects of pseudoephedrine.
- Blood Pressure Medications: Pseudoephedrine can potentially decrease the effectiveness of antihypertensive drugs.
- Digoxin: Pseudoephedrine can increase the risk of cardiac arrhythmias in patients taking digoxin.
- Stimulants and ADHD Medications: Pseudoephedrine can have additive effects with other stimulants.
- Antacids: May increase pseudoephedrine absorption.
- Kaolin: May decrease pseudoephedrine absorption.
- CYP450 Interactions: Cetirizine and pseudoephedrine have limited CYP450 interactions compared to other drugs. However, pseudoephedrine may affect the metabolism of drugs metabolized by CYP2D6.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C
- Fetal Risks: The safety of this combination during pregnancy has not been established. Use only if the potential benefit outweighs the risk to the fetus. Pseudoephedrine can decrease blood flow to the uterus.
- Breastfeeding: Both cetirizine and pseudoephedrine can pass into breast milk. Use is generally not recommended during breastfeeding. Small, infrequent doses of cetirizine may be acceptable, but large or prolonged use, especially in combination with pseudoephedrine, may decrease milk production and cause irritability in the infant.
Drug Profile Summary
- Mechanism of Action: Cetirizine: H1 receptor antagonist; Pseudoephedrine: Alpha-adrenergic agonist
- Side Effects: Dry mouth, drowsiness, headache, insomnia, dizziness, nausea, nervousness, tachycardia, severe allergic reactions, cardiac arrhythmias, hypertension, difficulty urinating.
- Contraindications: Hypersensitivity, narrow-angle glaucoma, urinary retention, severe hypertension/CAD, MAOI use, uncontrolled hyperthyroidism, severe arrhythmia.
- Drug Interactions: CNS depressants, MAOIs, tricyclic antidepressants, blood pressure medications, digoxin, stimulants.
- Pregnancy & Breastfeeding: Use with caution during pregnancy; not recommended during breastfeeding.
- Dosage: Adults: 1 tablet every 12 hours (max 2 tablets/day). Adjust for elderly, renal/hepatic impairment.
- Monitoring Parameters: Blood pressure, heart rate, mental status.
Popular Combinations
Cetirizine + Pseudoephedrine is itself a combination product. Combining it with other medications for allergy or cold symptoms is generally discouraged unless under the guidance of a healthcare professional.
Precautions
- General Precautions: Assess for allergies, renal/hepatic impairment, cardiovascular disease, diabetes, glaucoma, prostatic hypertrophy before administering.
- Specific Populations: Use caution in pregnant or breastfeeding individuals, children under 12 and the elderly.
- Lifestyle Considerations: Avoid alcohol, operating machinery while experiencing drowsiness, and consider potential effects on driving.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cetirizine + Pseudoephedrine?
A: Adults and children 12 years and older: One tablet every 12 hours, not to exceed two tablets in 24 hours. Elderly patients and those with moderate to severe renal or hepatic impairment should generally start with one tablet daily.
Q2: Can I crush or chew the extended-release tablet?
A: No, the extended-release tablet should be swallowed whole. Crushing or chewing it can alter the release of the medication and increase the risk of side effects.
Q3: What are the common side effects?
A: Common side effects include dry mouth, drowsiness, headache, insomnia, and dizziness.
Q4: Can I take Cetirizine + Pseudoephedrine if I have high blood pressure?
A: Use caution in patients with high blood pressure. Pseudoephedrine can elevate blood pressure further. Consult a physician before use.
Q5: Can I take this medication if I am pregnant or breastfeeding?
A: Consult a physician before using during pregnancy. It is generally not recommended during breastfeeding.
Q6: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it’s almost time for the next dose. Do not double the dose.
Q7: Can I drink alcohol while taking this medication?
A: It’s best to avoid alcohol while taking Cetirizine + Pseudoephedrine. Alcohol can enhance the sedative effects of cetirizine.
Q8: What are the signs of an allergic reaction to this medicine?
A: Signs of an allergic reaction include hives, difficulty breathing, and swelling of the face, lips, tongue, or throat. Seek immediate medical attention if these symptoms occur.
Q9: Can I take this medication with other cold or allergy medicines?
A: Consult a physician or pharmacist before combining Cetirizine + Pseudoephedrine with other cold or allergy medicines. Some medications may contain the same ingredients, and combining them could lead to an overdose. Avoid taking other products containing cetirizine, pseudoephedrine, or other antihistamines or decongestants.
Q10: Can this medicine interact with other medications I am taking?
A: Yes, Cetirizine + Pseudoephedrine can interact with various medications, including certain antidepressants, blood pressure medications, and heart medications. Inform your doctor about all medications you are taking, including prescription, over-the-counter drugs, and herbal supplements.
