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.
Taking more than the usual dose is unlikely to harm you or your child. If you take an extra dose, you might get some of the common side effects. If this happens or you're concerned, contact your doctor.
Toxic doses of antihistamines may happen when a person takes 3 to 5 times the normal amount. No matter how much a person overdoses, they should seek medical help or call a poison control center.
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.
ZYRTEC® Allergy Dye-Free Chewables
Adults and children 6 years and older Chew and swallow 2 tablet (10 mg) once daily; do not take more than 1 tablet (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.
For adults and children over 12 years of age, the maximum is 300 mg each day. For children ages 6 to 12 years, the maximum is 150 mg each day. For adults or children, Benadryl products such as the cream, gel, and spray shouldn't be applied to the skin more than 4 times per day.
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.
There have been reports of patients taking 15-18 times the recommended dose of Zyrtec (recommended dose is 10 mg) and having some adverse effects (restlessness, irritability, somnolence). Taking two 10mg tablets should not cause you to have any serious problems.
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.
Do not take more than the recommended dose and remember, this medicine is for you. Do not give it to anyone else, even if their symptoms seem to be the same as yours. If Telfast does not relieve your symptoms, do not take extra tablets. Tell your doctor or pharmacist.
Cetirizine is the most potent antihistamine available and has been subjected to more clinical study than any other.
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.
Taking 10mg of Zyrtec is more effective than taking 5mg; taking 20mg appears not to provide any additional effect. Food has no effect on the overall absorption of Zyrtec; however, it may increase the time it takes for peak levels of Zyrtec to be reached in the blood.
Directions. take 1 tablet every 12 hours; do not take more than 2 tablets in 24 hours.
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.
If you take too much Telfast, you may feel dizzy, drowsy or have a dry mouth.
No interactions were found between Claritin and Zyrtec. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.
The evidence presented does suggest, however, that patients on prolonged antihistamine therapy may develop clinical tolerance. When this is suspected the dose should be increased or the drug discontinued for a short perior (3 to 14 days) before resuming therapy.
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.
With ingestions greater than 1 gram, diphenhydramine may result in delirium, psychosis, seizures, coma, and death. 5. There is an even greater risk of seizures, coma, and death when ingestions are greater than 1.5 grams of diphenhydramine. 6. Fatal deaths have also been reported with oral doses greater than 20 mg/kg.
Cetirizine has the fastest onset of action among the newer antihistamines. Fexofenadine does not impair psychomotor or cognitive skills and shows no dose-related increase in sedation but has a slower onset of action than diphenhydramine and cetirizine.
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.