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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Allery Relief 24hr
Generic Name
Allery Relief 24hr
Active Ingredient
Levocetirizine DihydrochlorideCategory
Other
Variants
1
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 5 mg/1 | TABLET, FILM COATED | ORAL | 69168-451 |
Detailed information about Allery Relief 24hr
References used for this content
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Allery Relief 24hr, you must consult a qualified healthcare professional.
Levocetirizine Dihydrochloride is a second-generation H1-receptor antagonist used to treat allergic rhinitis and chronic idiopathic urticaria. It provides 24-hour relief by selectively inhibiting peripheral histamine receptors.
For adults and adolescents 12 years of age and older, the standard recommended dose of Levocetirizine Dihydrochloride is 5 mg once daily. Clinical data suggests that taking the medication in the evening is most effective for many patients, as it ensures peak levels are present the following morning when allergy symptoms are often most severe, and it allows any potential somnolence (drowsiness) to occur during sleep.
For patients with Chronic Idiopathic Urticaria, the dose remains 5 mg once daily. It is important not to exceed this dose, as clinical trials have shown that higher doses do not necessarily provide additional relief but do significantly increase the risk of side effects.
Pediatric dosing is strictly based on age to ensure safety and efficacy:
Because the kidneys are the primary route for removing this drug from the body, dosage adjustments are mandatory for patients with reduced kidney function.
In patients with purely hepatic (liver) impairment, no dosage adjustment is typically required because the liver plays a minimal role in metabolizing the drug. However, if a patient has both liver and kidney impairment, the renal guidelines must be followed.
Selection of the dose for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not double the dose to catch up, as this increases the risk of excessive sedation.
Symptoms of overdose in adults may include extreme drowsiness. In children, an overdose may initially cause agitation and restlessness, followed by drowsiness. In the event of a suspected overdose, contact your local Poison Control Center or seek emergency medical attention immediately. Treatment is generally supportive, as there is no specific antidote for levocetirizine, and it is not effectively removed by dialysis.
> Important: Follow your healthcare provider's dosing instructions precisely. Do not adjust your dose or stop taking the medication without medical guidance, as your symptoms may return.
While Levocetirizine Dihydrochloride is generally well-tolerated, some patients may experience side effects. The most commonly reported side effect is somnolence (drowsiness or sleepiness). Although it is a second-generation antihistamine, approximately 6% of adults in clinical trials reported some level of tiredness. This effect is dose-dependent and varies by individual sensitivity.
Other common side effects include:
These effects occur in a smaller percentage of the population but are well-documented:
Rarely, patients may experience:
In rare instances, Levocetirizine Dihydrochloride can cause severe reactions. You should contact emergency services or your doctor immediately if you experience:
> Warning: Stop taking Levocetirizine Dihydrochloride and call your doctor immediately if you experience any signs of a serious allergic reaction or inability to urinate.
For most people, levocetirizine is safe for long-term use when taken as directed. However, some patients may develop a 'rebound' effect if the medication is stopped abruptly after years of use. This is known as discontinuation pruritus (intense itching after stopping the drug). This itching can be severe and may last for several days or weeks before resolving. It is not an allergic reaction to the drug's absence but rather a physiological response of the H1 receptors. If you have been taking levocetirizine for a long duration, discuss a tapering schedule with your doctor.
There are currently no FDA black box warnings for Levocetirizine Dihydrochloride. It is considered to have a high safety profile when used according to the established dosing guidelines and in the absence of severe renal impairment.
Report any unusual symptoms or side effects to your healthcare provider. Monitoring your body's response is essential for safe long-term allergy management.
Levocetirizine Dihydrochloride, while effective, requires careful use under certain conditions. The most critical safety point is the risk of Central Nervous System (CNS) depression. Patients must be aware that even though it is marketed as a non-drowsy antihistamine, it can cause significant somnolence in some individuals. This risk is compounded when the drug is taken with other substances that also depress the CNS, such as alcohol or sedatives.
No FDA black box warnings for Levocetirizine Dihydrochloride. It is generally regarded as safe for the general population when renal function is taken into account.
Patients with a known hypersensitivity to levocetirizine, cetirizine (Zyrtec), or hydroxyzine (Atarax) should never use this medication. Cross-sensitivity is common among these chemically related compounds. A severe reaction can lead to anaphylaxis, which is life-threatening.
Levocetirizine should be used with caution in patients with pre-disposing factors for urinary retention, such as prostatic hypertrophy (enlarged prostate) or spinal cord lesions. Antihistamines can decrease bladder contractility, making it difficult to urinate. If you experience difficulty starting a stream or feel your bladder is not emptying, consult your doctor immediately.
As the kidneys are responsible for clearing over 80% of the drug, any degree of renal impairment significantly increases the concentration of the drug in the blood. This increases the risk of toxic effects. Regular monitoring of Creatinine Clearance (CrCl) is necessary for patients with known kidney disease.
For most healthy patients, routine lab work specifically for levocetirizine is not required. However, for specific groups:
Patients are cautioned against engaging in hazardous occupations requiring complete mental alertness and motor coordination, such as operating machinery or driving a motor vehicle, until they know how Levocetirizine Dihydrochloride affects them. In clinical trials, somnolence was reported in a significant minority of patients, and its effects can be unpredictable.
Concurrent use of Levocetirizine Dihydrochloride with alcohol or other CNS depressants should be avoided. Alcohol can potentiate (increase) the sedative effects of the antihistamine, leading to severe impairment of judgment and physical coordination.
There is no evidence of physical addiction to levocetirizine. However, as mentioned in the side effects section, some patients experience intense itching (pruritus) upon stopping the medication after long-term use. If you plan to stop the medication after several months of daily use, your doctor may suggest gradually reducing the frequency of the dose rather than stopping 'cold turkey.'
> Important: Discuss all your medical conditions, especially kidney disease or prostate issues, with your healthcare provider before starting Levocetirizine Dihydrochloride.
There are few absolute contraindications for drug combinations with levocetirizine; however, it must NEVER be used in patients with End-Stage Renal Disease (ESRD) who are on hemodialysis. In these patients, the drug cannot be cleared, leading to dangerous accumulation and toxicity.
Drugs such as benzodiazepines (e.g., diazepam, lorazepam), opioids (e.g., oxycodone, hydrocodone), and certain sleep medications (e.g., zolpidem) can have an additive effect with levocetirizine. This means the combination can cause extreme drowsiness, slowed breathing, and impaired motor skills.
Ritonavir, an antiviral used in the treatment of HIV, may increase the plasma levels of certain antihistamines. While the specific interaction with levocetirizine is less pronounced than with cetirizine, caution is advised.
A small decrease (about 16%) in the clearance of levocetirizine has been observed when taken with theophylline (a bronchodilator). While not typically clinically significant for most, it may increase the half-life of the antihistamine slightly.
As noted, alcohol is the most significant 'food' interaction. Even small amounts of alcohol can significantly increase the drowsiness caused by levocetirizine.
Taking levocetirizine with a high-fat meal does not change the total amount of drug your body absorbs, but it does slow down how fast it gets into your system. If you need immediate relief from a sudden allergy flare-up, taking it on an empty stomach may result in slightly faster onset.
Supplements such as Valerian root, Kava, and Melatonin may increase the sedative effects of levocetirizine.
While St. John's Wort primarily affects drugs metabolized by the CYP3A4 enzyme (which levocetirizine does not rely on heavily), it can affect various transport proteins. Patients should inform their doctor if they use this herbal supplement.
Levocetirizine Dihydrochloride can interfere with the results of allergy skin tests. Because the drug prevents the skin from reacting to allergens, it can cause a 'false negative' result.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter cold and flu medicines which may also contain antihistamines.
There are specific circumstances where Levocetirizine Dihydrochloride must never be used due to the high risk of harm:
These are conditions where the drug should be used only if the benefits outweigh the risks, and under close medical supervision:
Patients should be aware of cross-sensitivity with other piperazine derivatives. If you have had a severe rash, hives, or breathing trouble after taking Zyrtec (cetirizine) or Vistaril/Atarax (hydroxyzine), you are highly likely to have the same reaction to Levocetirizine Dihydrochloride. Always provide a full list of drug allergies to your pharmacist.
> Important: Your healthcare provider will evaluate your complete medical history, including your kidney function and past reactions to antihistamines, before prescribing Levocetirizine Dihydrochloride.
Levocetirizine Dihydrochloride was previously classified as Pregnancy Category B. This means that animal reproduction studies have failed to demonstrate a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women.
Levocetirizine is expected to be excreted in human milk, as cetirizine is known to pass into breast milk.
Levocetirizine is FDA-approved for pediatric use down to 6 months of age.
Clinical studies did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. However, because elderly patients are more likely to have decreased renal function, dose selection should be cautious.
As discussed, the dose must be adjusted based on the severity of kidney disease. In patients with moderate to severe impairment, the dosing interval is increased (e.g., taking the pill every 3 days instead of every day) to prevent the drug from building up to dangerous levels.
No dosage adjustment is required for patients with liver disease alone. The drug is primarily excreted unchanged by the kidneys, so the liver's metabolic capacity does not significantly affect how the drug is cleared.
> Important: Special populations, particularly the elderly and those with kidney disease, require individualized medical assessment and frequent monitoring to ensure the medication remains safe and effective.
Levocetirizine Dihydrochloride is the (R)-enantiomer of cetirizine. It is a potent and selective peripheral H1-receptor antagonist. Its primary action is to compete with endogenous (naturally occurring) histamine for H1-receptor sites on the effector cells.
At the molecular level, levocetirizine is considered an inverse agonist. This means it does not just block the receptor but actually stabilizes it in its inactive form, further reducing the 'leakage' of inflammatory signals even when histamine levels are low. It has a high affinity for the H1 receptor—approximately two times higher than that of cetirizine. Because it dissociates (detaches) from the receptor very slowly, it provides a long duration of action, allowing for once-daily dosing.
| Parameter | Value |
|---|---|
| Bioavailability | >70% (Rapidly absorbed) |
| Protein Binding | 91% - 92% |
| Half-life | 8 - 9 hours (Adults) |
| Tmax | 0.9 hours |
| Metabolism | Minimal (<14%), non-CYP dependent |
| Excretion | Renal 85.4%, Fecal 12.9% |
Levocetirizine belongs to the Second-Generation Antihistamine class. It is specifically a 'systemic antihistamine' used for allergic conditions. It is closely related to cetirizine (Zyrtec) and hydroxyzine (Atarax). Compared to first-generation drugs like diphenhydramine (Benadryl), it is significantly less sedating and has a longer half-life.
Common questions about Allery Relief 24hr
Levocetirizine Dihydrochloride is primarily used to relieve symptoms associated with seasonal and year-round allergies, such as sneezing, runny nose, and itchy eyes. It is also FDA-approved to treat chronic idiopathic urticaria, which are long-term hives of an unknown cause. By blocking histamine, it reduces the inflammatory response the body has to allergens like pollen or pet dander. Healthcare providers often recommend it because it provides 24-hour relief with a single dose. It is suitable for both adults and children as young as six months old, depending on the condition being treated.
The most frequently reported side effect of Levocetirizine Dihydrochloride is somnolence, or drowsiness, which affects about 6% of adult users. Other common issues include a dry mouth, fatigue, and a sore throat. In children, parents often report fever, cough, or occasional nosebleeds as common side effects. While these are usually mild, they can be bothersome for some patients. If these symptoms persist or become severe, it is important to consult a healthcare provider. Taking the medication in the evening can often help manage the daytime drowsiness.
It is generally advised to avoid alcohol while taking Levocetirizine Dihydrochloride. Alcohol can significantly increase the sedative effects of the antihistamine, leading to extreme drowsiness and impaired coordination. This combination can make activities like driving or operating machinery very dangerous. Even if you do not feel sleepy after taking the medication alone, alcohol can trigger a much stronger reaction. Always discuss your alcohol consumption habits with your doctor when starting a new medication. Safety is the priority when managing allergy symptoms.
Levocetirizine Dihydrochloride is often considered safe during pregnancy, but it should only be used if clearly necessary and under a doctor's supervision. Animal studies have not shown harm to the fetus, but there is limited data from high-quality human trials. Many doctors prefer using antihistamines with a longer track record of safety in pregnant women. If your allergy symptoms are severe, your healthcare provider will weigh the benefits of the medication against any potential risks. Always inform your obstetrician before starting any over-the-counter or prescription allergy relief. It is classified as Category B in the older FDA system.
Levocetirizine Dihydrochloride is a fast-acting medication, with most patients experiencing relief within about 60 minutes of ingestion. Peak levels of the drug in the bloodstream are typically reached in less than an hour. However, for conditions like chronic hives, it may take a few days of consistent use to see the full therapeutic benefit. Because it lasts for 24 hours, you only need to take it once a day to maintain its effects. If you do not feel any improvement after several days of use, you should contact your doctor. They may need to re-evaluate your diagnosis or adjust your treatment plan.
For most people, stopping Levocetirizine Dihydrochloride suddenly does not cause a traditional withdrawal syndrome. However, some patients who have used the drug daily for a long time report intense itching, known as pruritus, after stopping. This itching can be quite severe but usually resolves on its own within a few days or weeks. To avoid this, some doctors recommend tapering the dose by taking it every other day before stopping completely. If you are taking it for seasonal allergies, you can usually stop once the allergen season ends. Always consult your healthcare provider for the best way to discontinue long-term medications.
If you miss a dose of Levocetirizine Dihydrochloride, you should take it as soon as you remember. However, if it is nearly time for your next scheduled dose, you should skip the missed one and continue with your regular evening schedule. Never take two doses at the same time to make up for a missed one, as this significantly increases the risk of side effects like extreme drowsiness. Consistency is important for managing allergy symptoms effectively, so try to take it at the same time each night. If you frequently forget your doses, using a pill organizer or phone alarm can be helpful. Skipping a single dose may cause a brief return of allergy symptoms.
Weight gain is not a common side effect of Levocetirizine Dihydrochloride, but it has been reported in a very small number of patients during long-term clinical trials. Antihistamines as a class can sometimes interfere with the body's hunger signals, leading to a slight increase in appetite for some individuals. However, this effect is much more common with older, first-generation antihistamines than with newer ones like levocetirizine. If you notice significant or rapid weight gain while taking this medication, it is important to discuss it with your doctor to rule out other causes. For the vast majority of users, weight remains stable during treatment.
Levocetirizine Dihydrochloride can interact with other medications, particularly those that cause sleepiness. You should be cautious if taking it alongside muscle relaxants, sleep aids, or opioid pain medications, as the sedative effects can be additive. It can also interact with theophylline, a medication used for asthma, which might slightly change how the antihistamine is cleared from your body. Most common medications like antibiotics or birth control pills do not have known interactions with levocetirizine. However, you should always provide your healthcare provider with a complete list of all supplements and drugs you use. This ensures that your allergy treatment does not interfere with your other health needs.
Yes, Levocetirizine Dihydrochloride is widely available as a generic medication. Since the patent for the original brand-name drug, Xyzal, expired, many manufacturers produce high-quality generic versions that are just as effective. Generic versions are available both by prescription and over-the-counter (OTC) in many countries. Choosing the generic version can often save patients a significant amount of money while providing the same 24-hour allergy relief. Both the tablet and the oral solution forms are typically available as generics. Check with your pharmacist to find the most cost-effective option for your specific prescription.
Other drugs with the same active ingredient (Levocetirizine Dihydrochloride)