As well as taking a non-drowsy antihistamine during the day (such as cetirizine or loratadine), your doctor may advise that you take a drowsy antihistamine at night time if the itching is making it difficult to sleep. Do not take 2 antihistamines together unless recommended by your doctor.
Antihistamines are used to relieve or prevent the symptoms of your medical problem. Take them only as directed. Do not take more of them and do not take them more often than recommended on the label, unless otherwise directed by your doctor. To do so may increase the chance of side effects.
Official answer. No, the maximum recommended daily dose of loratadine is 10mg once daily.
Don't take more than 1 tablet in 24 hours. Children's Zyrtec (ages 2+) chewable tablets contain 2.5 mg of cetirizine per tablet. If you are under 65 years old, chew and swallow 2 to 4 tablets (5 mg to 10 mg) once daily.
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.
Do not take 2 antihistamines together unless recommended by your doctor.
The recommended dose is one tablet (180 mg) daily. Take your tablet with water before a meal. This medicine starts to relieve your symptoms within 1 hour and lasts for 24 hours. If you take too many tablets, contact your doctor or the nearest hospital emergency department immediately.
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.
ZYRTEC 10 mg film-coated tablets
Others may need to take 20 mg, e.g. larger people or those who find that 10 mg is not enough. The maximum recommended daily dose is 20 mg, do not exceed this dose, unless told to do so by your doctor.
It's natural to worry if you realize you've accidently doubled your dose, but in most cases, you won't need to do anything if you mistakenly take two pills. Even children usually don't need treatment after a double dose. Just manage any symptoms you or your child has.
The usual dose for treating hives is 180mg once a day for adults and children aged 12 years and over. Fexofenadine is not recommended for treating hives in children under 12.
How long to wait between doses of two oral antihistamines depends on the specific medications. If you've taken an antihistamine like Zyrtec, its effects can last for up to 24 hours. So you'd want to wait until it's been at least 24 hours since taking Zyrtec to take Benadryl (or another antihistamine).
Sedating antihistamines
As well as sedation, overdose often presents with anticholinergic symptoms (see Anticholinergic Syndrome). At higher doses, they can also cause sodium channel blockade with subsequent cardiovascular effects including QT prolongations and Torsades de Pointes.
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.
What happens if I take more than one dose of Claritin®? Taking more than the recommended dose of Claritin® may cause drowsiness. In the case of overdose, get medical help or contact a Poison Control Center right away- always follow label directions. See individual product pages for label directions.
Some antihistamines are taken every 4 to 6 hours, and some are longer-lasting antihistamines that are taken every 12 to 24 hours. Consult the drug label and ask your health care provider how long and how often you should take an antihistamine.
Zyrtec. Zyrtec (cetirizine) is the strongest of the second-generation antihistamines, says Dr. Garcia-Ibáñez. And because there is less chance of toxicity with this medication, the dosage can be increased substantially, at the discretion of your doctor, he says.
Medically reviewed by Drugs.com. Last updated on Mar 11, 2022. one 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours.
Take 1 tablet every 12 hours; do not take more than 2 tablets in 24 hours.
Cetirizine can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening. Cetirizine can be taken with or without food.
For the relief of the symptoms of seasonal and perennial allergic rhinitis (including hayfever), the usual dosage for adults and children over 12 years old is one Telfast 60 mg tablet twice daily, when required.
Telfast 180mg is the highest strength of Telfast available — it contains 180mg of the active ingredient fexofenadine hydrochloride (HCl). Fexofenadine HCl acts quickly (within 1 hour) without causing drowsiness to help relieve the symptoms of hayfever allergies by blocking histamine receptors in the body.
Allevia Fexofenadine 120 mg strong Hayfever Tablets provide relief that lasts all day from 7 hayfever symptoms in just 1 tablet, including sneezing, itchy, red, watery eyes, itchy, blocked, and runny nose.