Alzene is a medication containing the active ingredient cetirizine hydrochloride, a second-generation antihistamine used to treat various allergic conditions. It works by blocking the action of histamine, a natural substance in the body that triggers allergic symptoms like sneezing, runny nose, and itching. While generally considered safe for use, patients should be aware of the full spectrum of potential side effects, both common and rare, to ensure safe and effective treatment. Most common side effects tend to be mild and often subside as the body adjusts to the medication. However, more serious side effects, though infrequent, require immediate medical attention.
Common Side Effects of Alzene
Many patients using Alzene will experience only minor side effects, or none at all. These reactions are typically mild and temporary, and they are frequently linked to the medication's antihistamine properties. These include:
- Drowsiness or Sleepiness (Somnolence): This is one of the most common side effects reported with cetirizine. While a second-generation antihistamine like cetirizine is less sedating than first-generation counterparts, it can still cause sleepiness, especially in higher doses. If affected, it's recommended to take the medication in the evening.
- Fatigue: A general feeling of tiredness and weakness is another frequently reported symptom.
- Dry Mouth: Users may experience dryness in the mouth, which can often be managed with sugar-free candy or gum.
- Headache: Mild to moderate headaches can occur in some patients.
- Gastrointestinal Issues: These can include nausea, vomiting, or abdominal pain.
- Inflammation: A sore throat or nasopharyngitis (inflammation of the throat and nasal passages) has been noted in some cases.
Serious and Rare Side Effects
While rare, some side effects are more serious and require a doctor's immediate attention. It is crucial to be vigilant for any unusual or severe symptoms while taking Alzene.
Allergic Reactions
In rare instances, a severe allergic reaction (anaphylaxis) can occur. Symptoms include:
- Rash, itching, or hives
- Swelling of the face, lips, tongue, or other body parts
- Shortness of breath, wheezing, or trouble breathing
Rebound Pruritus
In May 2025, the FDA issued a warning regarding a rare risk of severe itching, or rebound pruritus, that can occur after discontinuing long-term use of cetirizine, the active ingredient in Alzene. This can occur after months or even years of regular use. Patients who experience severe itching after stopping the medication should consult a healthcare provider.
Other Rare Adverse Effects
- Seizures/Epilepsy: Antihistamines can cause CNS stimulation, especially in children, and patients with epilepsy or a history of seizures should use Alzene with caution.
- Urinary Retention: Some patients may experience difficulty or inability to empty their bladder.
- Visual Disturbances: Blurred vision has been reported in rare cases.
- Aggressive Reactions or Confusion: Although rare, some individuals have reported mood changes or irrational behavior.
Comparison of Alzene with Other Antihistamines
| Feature | Alzene (Cetirizine) | First-Generation Antihistamines (e.g., Diphenhydramine) | Other Second-Generation Antihistamines (e.g., Loratadine) |
|---|---|---|---|
| Sedation | Less sedating than first-gen, but can still cause drowsiness | Highly sedating; often used as a sleep aid | Generally non-drowsy |
| Speed of Action | Starts working relatively quickly, often within an hour | Can have a quick onset due to crossing the blood-brain barrier | May take longer to show full benefits than Alzene |
| Effect on CNS | Minimal CNS effects due to low blood-brain barrier penetration | Significant CNS effects, including drowsiness and impaired mental function | Minimal CNS effects |
| Metabolism | Minimally metabolized; primarily excreted by the kidneys | Extensive liver metabolism; more variable effects and interactions | Metabolized in the liver to desloratadine |
| Drug Interactions | Potential interactions with CNS depressants like alcohol and benzodiazepines | Numerous potential interactions due to liver metabolism | Fewer drug interactions than first-gen, but still possible |
Important Precautions and Warnings
Before taking Alzene, or any medication, it is essential to consider safety precautions to minimize risks and adverse events.
- Avoid Alcohol: Consuming alcohol while on Alzene can significantly increase the risk of drowsiness, dizziness, and sedation.
- Driving and Machinery: Due to the potential for dizziness and sleepiness, users should exercise caution when driving or operating heavy machinery until they understand how the medication affects them.
- Patients with Kidney Problems: Since cetirizine is primarily excreted through the kidneys, individuals with kidney dysfunction may require a dosage adjustment under a doctor's supervision.
- Epilepsy/Seizure Risk: Patients with a history of epilepsy or seizures should be cautious as antihistamines can cause CNS stimulation.
- Elderly Patients: Older patients may be more susceptible to side effects and may require a lower dose, especially if their kidney function is reduced.
- Pregnancy and Breastfeeding: Pregnant or breastfeeding individuals should consult their doctor before using Alzene. Limited data suggests the drug may pass into breast milk.
- Pre-Surgery or Allergy Testing: It is recommended to stop taking Alzene at least three days before an allergy skin prick test, as it can affect the results.
Drug Interactions to Note
It is important to inform your healthcare provider about all medications, supplements, and herbal products you are taking. Interactions can increase the risk of side effects.
- CNS Depressants: Taking Alzene with other CNS depressants, such as certain antidepressants, anti-anxiety medications (like benzodiazepines), or sleeping pills, can amplify the sedative effects.
- Other Antihistamines: Combining Alzene with other antihistamines can increase the risk of side effects and potentially lead to an overdose.
What to Do in Case of Overdose
If you suspect an overdose, seek immediate medical attention. Overdose symptoms may include excessive drowsiness, irritability, and restlessness. You may need urgent medical care. If you have taken too much Alzene, do not drive. For information, contact the Poisons Information Centre or go to the nearest Accident and Emergency department.
Conclusion
As an effective antihistamine, Alzene (cetirizine) provides relief from allergic symptoms for many individuals. The drug's side effects are typically mild and manageable, such as drowsiness, fatigue, and dry mouth. However, it is essential to be aware of the more serious, though rare, side effects, including severe allergic reactions, seizures, and rebound itching upon discontinuation. NPS MedicineWise provides comprehensive patient information. Always adhere to the recommended dosage, avoid alcohol, and consult a healthcare professional regarding any pre-existing conditions or concerns, especially for special populations like the elderly or those with kidney problems. Being informed and cautious allows for the safest and most effective use of this medication.
