Cetirizine is generally very safe. Taking more than the usual dose is unlikely to harm you or your child.
ZYRTEC® Liquid Gels with Active Ingredient Cetirizine HCl
Children under 6 years of age Ask a doctor. Adults under 65 and children 6 years and older One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less sever symptoms.
Medically reviewed by Drugs.com. Last updated on Oct 18, 2021. take 1 tablet every 12 hours; do not take more than 2 tablets in 24 hours.
Adults and children 6 years and older can take cetirizine capsules and tablets. The usual dosage for adults younger than 65 years and children who are 6 years and older is one 10-milligram (mg) dose per day. You shouldn't take more than 10 mg in 24 hours.
Do NOT "double-up" on a dose. Do NOT take a dose sooner than you're supposed to. Do NOT take two different antihistamines at the same time. Instead, talk to your doctor or pharmacist if you have trouble finding a drug that works well for your allergy symptoms.
Different oral antihistamines such as diphenhydramine, cetirizine, loratadine, levocetirizine, desloratadine, and fexofenadine should never be taken together. Taking different oral antihistamines together can lead to an antihistamine overdose. Signs of an overdose may include the following: Fast or racing heartbeat.
DIRECTIONS. Adults and children 6 years and over: One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less severe symptoms.
ZYRTEC 10 mg film-coated tablets
The maximum recommended daily dose is 20 mg, do not exceed this dose, unless told to do so by your doctor.
Deaths from antihistamine overdose
There have been reports of death due to antihistamine toxicity. These include accidental overdoses and intentional misuse. Death can occur when an overdose causes severe complications such as respiratory distress, cardiac arrest, or seizures.
Although Zyrtec is unlikely to make you drowsy, some people are susceptible to this effect, especially if they are taking dosages at the upper end of the recommended dosage range. Do not drive or operate machinery if Zyrtec makes you drowsy.
Antihistamines that can cause weight gain include: Diphenhydramine (Benadryl and others) Cetirizine (Zyrtec) Levocetirizine (Xyzal)
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The elimination half-life of Zyrtec is between 8 to 9 hours. It takes approximately 5.5 x elimination half-life for a medicine to be cleared from your system. For Zyrtec this is 5.5 x 9 hours which is about 2 days.
If there is no histamine, then antihistamines can't relieve symptoms. If antihistamines aren't working for you and you have allergy-like symptoms, it may not be a bad allergy season—but instead something non-allergic you're reacting to.
All ZYRTEC® medicines start working at hour 1 on the first day you take it.
Greg Panico, a spokesman for Janssen Pharmaceutica, which is owned by Johnson and Johnson, said that the withdrawal was a voluntary business decision. “The decision to voluntarily discontinue it recognises that the allergy marketplace is crowded with a number of other drugs,” Mr Panico said.
If a healthy adult takes only a slightly higher dose of antihistamine, such as accidentally taking two pills instead of one, their symptoms may not be serious, or they may not have any symptoms. However, a larger overdose, especially in children or older adults, may cause serious symptoms.
The U.S. Food and Drug Administration (FDA) is warning that taking higher than recommended doses of the common over-the-counter (OTC) allergy medicine diphenhydramine (Benadryl) can lead to serious heart problems, seizures, coma, or even death.
Why do antihistamines stop working? Antihistamines can stop working because your allergies might be getting worse or you might have immune system changes due to aging. You also might not be taking the medication as directed. If you take an antihistamine after being exposed to an allergy trigger, it won't work as well.
Cetirizine is the most potent antihistamine available and has been subjected to more clinical study than any other.
Does Zyrtec-D (cetirizine / pseudoephedrine) cause trouble sleeping? It can. If taken too close to bedtime, some people find Zyrtec-D (cetirizine / pseudoephedrine) makes it hard for them to get to sleep. The best way to prevent this is to take your dose in the morning or in the early afternoon.
While most anticholinergics can be modified or monitored when taken with loratadine or cetirizine, several should be avoided entirely, including aclidinium, cimetropium, glycopyrrolate, glycopyrronium, ipratropium, oxatomide, tiotropium, and umeclidinium.
One study also suggests cetirizine and hydroxyzine have a greater chance of causing anxiety and mood changes than other antihistamines. Hydroxyzine can also be used to treat anxiety conditions. So if you notice your symptoms worsen after starting this medication, contact your provider to discuss it further.
Histamine H1 receptor antagonist cetirizine impairs working memory processing speed, but not episodic memory.
Both Zyrtec and Claritin may make you drowsy or tired. For that reason, you shouldn't take these medications if you also take muscle relaxers, sleeping pills, or other drugs that cause drowsiness. Taking them at the same time that you take sedating drugs can make you extremely sleepy.
Yes, you can take cetirizine (Zyrtec) only when you need it if you have allergy symptoms once in a while. But if you have allergy symptoms on a daily basis, taking it regularly according to the manufacturer's directions might give you the most relief from your allergies.