Antihistamines are a class of medication the treat allergy symptoms, such as sneezing, runny nose, and itching. As with any medication, taking as well much can be harmful.

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Some antihistamines likewise work together sleep aids, cold and flu medicine, and motion sickness treatment.

People need to follow the dosage accuse on the packaging or your doctor’s advice to prevent an overdose. Castle should likewise keep antihistamines, and all medications, the end of with of children.

If a human being takes too much antihistamine, they might experience adverse and sometimes major effects. Constantly call a physician or a toxicity control center if one antihistamine overdose occurs.

Share top top PinterestA human who overdoses ~ above antihistamines might experience fever, dilated pupils, and a quick heart rate.
People can overdose on any type of antihistamine. Antihistamines are a drug, and there is a safe limit to just how much a person have the right to take in ~ one time.

This limit relies on number of factors, including:

the age and size of the personthe kind of antihistamine lock took and how muchany health conditions they have other medicine the person takes

If a healthy adult takes only a slightly greater dose the antihistamine, such as accidentally taking two pills rather of one, your symptoms may not it is in serious, or they may not have any symptoms.

However, a larger overdose, particularly in youngsters or larger adults, may cause serious symptoms. Toxic doses that antihistamines may occur when a human being takes 3 come 5 time the common amount.

No matter how much a person overdoses, they should seek medical aid or speak to a poison control center.


A place statement indigenous the Canadian culture of Allergy and also Clinical Immunology (CSACI) states that very first generation antihistamines can have “intolerable and also potentially life threatening disadvantage effects.”

Research mirrors that very first generation antihistamines deserve to have impacts on the central nervous system in large doses.

Examples of an initial generation antihistamines include:

diphenhydramine (Benadryl)chlorpheniraminebrompheniramine

These antihistamines may cause jitteriness or drowsiness.

Second generation antihistamines perform not usually have actually these effects. Second-generation antihistamines are commonly used medications, including:

loratadine (Claritin)cetirizine (Zyrtec),fexofenadine (Allegra)

Signs and also symptoms that antihistamine overdose in kids may include:

being an extremely excited or jitteryirritabilityhallucinationsseizures

After these symptoms appear, a child may experience:

drowsinessslowed breathing

Symptoms of antihistamine overdose in adults may include:

flushingdilated pupilscomaan i can not qualify to empty the bladder fully (urinary retention)

Second generation antihistamines have tendency to be less serious v an overdose.However, any overdose deserve to be dangerous, and people must seek help from a medical professional or poison regulate immediately.

Some antihistamines are safe for youngsters to take. However, the Food and Drug management (FDA) caution the just due to the fact that a product states it is for children does not median a son of any age can take it.

Research top top antihistamines says that children and also older adults are an ext at danger of one antihistamine overdose 보다 adults.

One study uncovered that youngsters have proficient heart problems, seizures, and also even fatality from one antihistamine overdose. The most typical reactions are mild, however, and include:


Second generation antihistamines are less likely to cause toxicity in youngsters than very first generation ones, follow to a research of more than 9,000 children.

However, one more study foundthat second generation antihistamines can cause dangerous symptom when youngsters overdose on them.

Diagnosing an antihistamine overdose commonly starts with a discussion around all medicines the human being is taking and not simply the antihistamines. This is because some other medications, such as cold, flu, and sleep medications, save on computer antihistamines.

If a human being takes one of these other medications and also takes one allergy medication, they might accidentally overdose.

Other medications, together as certain antidepressants and also motion sickness drugs, can additionally cause one overdose if a human being mixes them v antihistamines.

If someone is not sure about the lot of antihistamine they took, a doctor may need to command a physics exam. They may look for indicators such as drowsiness, irritability, blurred vision, or seizures. Castle may additionally check the heart rate, breath rate, and blood pressure.

In part cases, a person may require blood test or further observation in a hospital.

In gentle cases, an individual may be able to use self-care at home. However, they should always call the AAPCC or a doctor to be sure this is safe.

If the person is experiencing significant symptoms, they may need hospitalization, consisting of heart monitoring, intravenous (IV) fluids, and also medication.

In some cases, doctors may give a human being activated charcoal, i beg your pardon helps prevent the absorb of part medications and also chemicals in the gut. Lock may also use ipecac syrup, which causes the person to vomit. This can cause any excess medicine to leave the body in the vomitus.

Antihistamines might be first generation (sedating) or 2nd generation (nonsedating). This two types may lead to various reactions if a person takes as well much.

First generation antihistamines are more likely to cross the blood-brain barrier. This way they have the right to make human being dizzy or drowsy, also in common doses.

Second generation antihistamines are more recent drugs and are much less likely to have these effects. Nonetheless, civilization can overdose on both types.

First generation antihistamines easily accessible over-the-counter include:

diphenhydramine (Benadryl) chlorpheniramine (Chlor-Trimeton)brompheniramine (Dimetapp)clemastine (Tavist)doxylamine (Unisom)hydroxyzine (Vistaril)promethazine (Promethegan)triprolidine (Actidil)

These medications have the right to act together sedatives, for this reason they deserve to make a human feel exhausted or dizzy.

Some professionals say an initial generation antihistamines are an ext likely to an outcome in death from accidents or overdoses 보다 their second generation counterparts.

Second and third generation antihistamines obtainable over the respond to include:

cetirizine (Zyrtec)fexofenadine (Allegra)loratadine (Claritin)

These newer antihistamines are much less likely to reason drowsiness and also dizziness. Research study has uncovered them much less likely to cause dangerous results if a human being takes also much.

Antihistamines are generally safe when a human takes the correct amount. However, as with any medication, castle can cause serious adverse results if someone takes also much.

People need to keep antihistamines and all drugs out of reach of children. Part antihistamines space safe for children to take, but it is crucial to asking a doctor or pharmacist about the appropriate dose.

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Different antihistamines have various dosages. It is critical to check out labels closely to be certain a person is not taking too much.

If an overdose happens, seek prompt medical fist or speak to the AAPCC at 800-222-1222.