Cetirizine + Phenylpropanolamine

Usage

Cetirizine + Phenylpropanolamine is primarily prescribed for the relief of symptoms associated with the common cold, allergies, and other upper respiratory tract conditions such as allergic rhinitis. This combination medication offers symptomatic relief from clogged nose, sneezing, runny and itchy nose, and itchy, watery eyes. It is categorized as a combination antihistamine and decongestant.

The cetirizine component works by blocking histamine H1 receptors, which reduces the effects of histamine, a chemical mediator responsible for allergic symptoms. Phenylpropanolamine, a decongestant, acts on alpha-adrenergic receptors, causing vasoconstriction in the nasal passages and reducing congestion.

Alternate Names

There are no widely recognized alternate generic names. Brand names may vary regionally. Alnix Plus is one example of a brand name.

How It Works

Pharmacodynamics: Cetirizine antagonizes the H1 histamine receptor, inhibiting histamine-mediated responses such as vasodilation, increased capillary permeability, and smooth muscle contraction in the airways. Phenylpropanolamine acts as an alpha-adrenergic agonist, causing vasoconstriction, which reduces nasal congestion.

Pharmacokinetics: Cetirizine is well-absorbed orally, with peak plasma concentrations reached in approximately 1 hour. It is primarily excreted unchanged in the urine. Phenylpropanolamine is also well-absorbed orally, metabolized in the liver, and excreted in the urine.

Mode of Action: Cetirizine competitively binds to H1 receptors, preventing histamine from binding and initiating its effects. Phenylpropanolamine stimulates alpha-adrenergic receptors in the nasal mucosa, leading to vasoconstriction, decreased blood flow, and reduced mucosal edema.

Elimination Pathways: Both Cetirizine and Phenylpropanolamine are primarily eliminated through renal excretion, with a smaller portion metabolized by the liver.

Dosage

Standard Dosage

Adults: One tablet (containing the typical combination of cetirizine 5mg and phenylpropanolamine 12.5 mg or 25mg depending on the formulation) every 12 hours. The maximum daily dose should not exceed two tablets.

Children:

Dosing varies based on age and formulation (syrup vs. tablet). Consult specific product information and pediatric guidelines. One formulation of syrup contains 5 mg cetirizine and 5 mg phenylpropanolamine per 5mL.

2-5 years old: 2.5 mL every 12 hours.

6-12 years old: 5 mL every 12 hours.

Special Cases:

• Elderly Patients: Dose reduction may be necessary. Start with a lower dose (e.g., 5 mg cetirizine daily) and adjust based on response and tolerance.

• Patients with Renal Impairment: Dose adjustment is required based on the degree of impairment.

• Patients with Hepatic Dysfunction: Dose adjustments may be necessary.

• Patients with Comorbid Conditions: Caution should be used in patients with diabetes, hypertension, cardiovascular disease, hyperthyroidism, and glaucoma. Individualized dosing and close monitoring are recommended.

Clinical Use Cases

This combination is not typically indicated for intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its use is primarily limited to outpatient management of cold and allergy symptoms.

Dosage Adjustments

Dose modifications are based on age, renal and hepatic function, and concomitant medications. Always refer to product-specific information for detailed dosage adjustments.

Side Effects

Common Side Effects

• Drowsiness
• Fatigue
• Dry mouth
• Nausea
• Headache
• Dizziness
• Insomnia
• Restlessness

Rare but Serious Side Effects

• Allergic reactions (rash, itching, swelling, difficulty breathing)
• Hypertension
• Tachycardia
• Cardiac arrhythmias
• Urinary retention
• Hallucinations

Long-Term Effects

Chronic use of phenylpropanolamine can lead to tolerance and rebound congestion.

Adverse Drug Reactions (ADR)

Clinically significant ADRs include severe allergic reactions, cardiac events, and hypertensive crisis. Immediate medical attention is required.

Contraindications

• Hypersensitivity to cetirizine or phenylpropanolamine.
• Severe hypertension or coronary artery disease.
• Severe renal impairment.
• Uncontrolled hyperthyroidism.
• Narrow-angle glaucoma.
• Monoamine oxidase inhibitor (MAOI) therapy.

Drug Interactions

• MAOIs: Concurrent use can lead to a hypertensive crisis.
• Alcohol: Increases the risk of central nervous system depression.
• Antihypertensives: May counteract the effects of antihypertensive medications.
• Other CNS depressants: Additive sedative effects may occur.

Pregnancy and Breastfeeding

Phenylpropanolamine is generally avoided during pregnancy, especially in the first trimester, due to concerns about potential birth defects and in the third trimester due to vasoconstrictive properties. Cetirizine is considered relatively safe during pregnancy, but should be used cautiously.

Both medications can be excreted in breast milk. Consult with a healthcare professional to assess the risks and benefits before use during breastfeeding.

Drug Profile Summary

• Mechanism of Action: Cetirizine: H1 receptor antagonist; Phenylpropanolamine: alpha-adrenergic agonist.
• Side Effects: Drowsiness, dry mouth, nausea, headache, dizziness. Serious side effects are rare but can include cardiac events and allergic reactions.
• Contraindications: Hypersensitivity, severe hypertension, severe renal impairment, MAOI therapy.
• Drug Interactions: MAOIs, alcohol, antihypertensives, CNS depressants.
• Pregnancy & Breastfeeding: Use cautiously during pregnancy. Excreted in breast milk. Consult with a physician.
• Dosage: Adults: One tablet every 12 hours, not to exceed two tablets daily. Pediatric dosing varies by age and formulation.
• Monitoring Parameters: Blood pressure, heart rate.

Popular Combinations

Cetirizine and phenylpropanolamine are often combined with analgesics and antipyretics like paracetamol/acetaminophen for broader symptomatic relief of cold and flu symptoms.

Precautions

• Patients with pre-existing medical conditions, such as diabetes, hypertension, cardiovascular disease, or glaucoma, should be monitored closely.
• Avoid operating machinery or driving while taking this medication due to the risk of drowsiness.
• Patients with renal or hepatic impairment may require dosage adjustments.
• Concurrent use of alcohol or other CNS depressants should be avoided.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Cetirizine + Phenylpropanolamine?

A: The standard adult dosage is one tablet (typically containing 5 mg cetirizine and 12.5-25 mg phenylpropanolamine depending on the formulation) every 12 hours, not to exceed two tablets in 24 hours. Pediatric dosing varies based on age and should be determined by a healthcare professional.

Q2: What are the primary uses of Cetirizine + Phenylpropanolamine?

A: This combination is used to relieve symptoms of the common cold, allergies, and allergic rhinitis, including nasal congestion, sneezing, runny nose, and itchy, watery eyes.

Q3: What are the common side effects?

A: Common side effects include drowsiness, fatigue, dry mouth, nausea, and headache.

Q4: Are there any serious side effects I should be aware of?

A: While rare, serious side effects can occur, including allergic reactions (rash, itching, swelling, difficulty breathing), cardiac events (hypertension, tachycardia, arrhythmias), and urinary retention. Seek immediate medical attention if these occur.

Q5: Can I take this medication if I have high blood pressure?

A: This medication should be used cautiously in patients with hypertension. It’s important to consult a doctor before taking it, as dose adjustments or alternative medications may be necessary.

Q6: Can I take this medication if I am pregnant or breastfeeding?

A: Phenylpropanolamine should generally be avoided during pregnancy, especially in the first and third trimesters. Cetirizine can be used cautiously during pregnancy. Both drugs are excreted in breast milk. Consult a physician before using this medication while pregnant or breastfeeding.

Q7: What are the potential drug interactions I should be aware of?

A: Avoid concurrent use with monoamine oxidase inhibitors (MAOIs), as this can lead to a hypertensive crisis. Alcohol and other CNS depressants can increase drowsiness. This combination may also interact with antihypertensive medications. Consult your doctor about all medications you are taking.

Q8: How does this medication work?

A: Cetirizine is an antihistamine that blocks the action of histamine, a substance in the body that causes allergic symptoms. Phenylpropanolamine is a decongestant that works by constricting blood vessels in the nasal passages, which reduces swelling and congestion.

Q9: Can I operate machinery or drive after taking this medication?

A: Use caution when driving or operating machinery, as this medication can cause drowsiness.

Q10: Are there any dietary restrictions while taking this medication?

A: There are no specific dietary restrictions. However, staying well-hydrated can help to relieve congestion.