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Doctor insights on: Antihistamine Tolerance

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I have noticed that my body is immune to loratadine based antihistamines (doesn't make me tired) but any others do. Does this means tolerance?

I have noticed that my body is immune to loratadine based antihistamines (doesn't make me tired) but any others do. Does this means tolerance?

Non-sedating: Loratadine is considered a non-sedating antihistamine. It is supposed to treat allergic symptoms without making you drowsy. Other older antihistamines like benadryl (diphenhydramine) are very sedating. ...Read more

Tolerance (Definition)

When one takes a drug, such as heroin or alcohol, repeatedly, 'tolerance' develops because more of the drug is needed to give the same effect on the body/brain; e.g. Liver enzymes r stimulated to metabolize the drug faster and faster. There may be a strong genetic predisposition to addiction, some studies suggesting that 1 of 10 people will become dependent on alcohol or some ...Read more


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What is the best OTC antihistamine?

OTC antihistamines: The second generation zyrtec, allergra or Claritin (loratadine) are comparative. None are perfect. Zyrtec is slightly more likely to make you tired ot sleepy. Often one works a little better than another and I adise you to test all three. ...Read more

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Is antihistamine harmful to the body?

Is antihistamine harmful to the body?

No: Antihistamines are a class of medication used since the 1940s. They are used to treat allergic conditions and are very safe. The newer generation antihistamines have even less side effects compared to first generation or old antihistamines. ...Read more

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When should you take an antihistamine?

When should you take an antihistamine?

Multiple reasons: Depending on the type of antihistamine used they can be used to treat things such as allergy symptoms, nausea, dizziness, motion sickness, anxiety, itching, and difficulty sleeping. ...Read more

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What are the common uses of antihistamine?

What are the common uses of antihistamine?

Antihistamine 4 itch: Antihistamines (ah) block histamine receptors and stop histamine from causing itching and swelling. They are mainly used to treat allergies and hives. Some are sedating; those are used as sleep aids. Many otc sleep meds contain Diphenhydramine (benadryl). ...Read more

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What is the best time to take an antihistamine?

Any time: You can take antihistamines any time of the day. Take them same time of day everyday. ...Read more

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Why young people more sensitive to antihistamine?

Why young people more sensitive to antihistamine?

Not true: Everyone reacts to medications differently although the differences may be minor in most cases. There is no study showing that young people are more sensitive to antihistamine, especially the newer ones. ...Read more

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Can I die by taking too many antihistamine tablets?

Can I die by taking too many antihistamine tablets?

Taking lethal over: Dose would do that. Lethal overdoses of antihistamines are rare. Are you considering taking an overdose of antihistamines? If so, please get help right away. You can use national suicide hotlines 24/7 at 1-800-suicide (1-800-784-2433) or 1-800-273 – talk (1-800-273-8255). If you have accidentally taken too many antihistamines please contact 1-800-222-1222 (poison control hotline). Take care. ...Read more

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What is the safest antihistamine for long term use?

What is the safest antihistamine for long term use?

New generation ones: Antihistamines in general are very safe. New generation products (Zyrtec, Claritin, (loratadine) Allegra, Xyzal) are just as effective with less side effects than older antihistamines (Benadryl, chlorpheniramine, hydroxyzine). However, it would be important to address WHY a person needs to take antihistamines long term? Consult with an allergist to assist in identifying the cause of symptoms. ...Read more

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Is there an herb which can be used as an antihistamine?

Yes: Butterbur has antihistamine-like effects. It can be found at health food stores. ...Read more

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Help please? What is a good yr round OTC antihistamine?

Antihistamine: All are good, zyrtec, allegra and claritin, (loratadine) but you should see an allergist if you need medicine all year round ...Read more

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Can you tell me what is the best medicine for antihistamine?

Can you tell me what is the best medicine for antihistamine?

New generation ones: The new generation antihistamines include Claritin, Zyrtec, Allegra and Xyzal (levocetirizine). These are as effective as older antihistamines (Benadryl, hydroxyzine, chlorpheniramine). Each person may respond differently to the different products and therefore trying them one at a time can be helpful. Since they are over-the-counter and generic (except for Xyzal (levocetirizine)), they are affordable and available. ...Read more

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Is it possible to die from an overdose of antihistamine pills?

Is it possible to die from an overdose of antihistamine pills?

Which one: First generation antihistamines are sedating, second generation ones are not, overdosing on the latter hardly kills, but may cause sedation. Overdosing on first generation antihistamines may be more of a problem, but again they are safe in high doses. ...Read more

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How many milligrams of antihistamine can a person take at one time?

Unclear: Different antihistamines have different potencies. 10 mg of Zyrtec is equivalent to 180mg of Allegra (fexofenadine). Mg doseage as in all medicines are drug specific. In regard to toxic levels, each has it's own known limit. However too much antihistamine can lead to deadly arrythmias/ Please use the recommended dose. ...Read more

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Is vistral and antihistamine the same or are they common medication?

Is vistral and antihistamine the same or are they common medication?

Antihistamine: Any medication that blocks chemical histamine, which causes allergy, is antihistamine. Vistaril (hydroxyzine) is one of these antihistamines. It is also used for sleep and sedation. ...Read more

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What is the average time needed for an antihistamine to begin to work?

45-90 minutes: Antihistamines taken by mouth begin to work in about an hour but may take longer if you've just eaten. Antihistamine nasal sprays (astepro, patanase) begin to work in 30 minutes. An antihistamine injection, usually diphenhydramine, sometimes given for a severe allergic reaction or anaphylaxis begins to work in a few minutes. ...Read more

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What is the highest dosage of antihistamine that one person can take at one time?

Antihistamines: Safety of high dose medications is often unknown. Our experience comes from case reports of persons who intentionally or accidentally consumed unusually excessive quantities. When Claritin (loratadine) was first investigated, safety studies were done at 40 mg (4 times the current recommended dose). We take 10 mg because effectiveness is not significantly different between 10 mg and 40mg. ...Read more

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I know it is not recommended to take more than one antihistamine pill per 24 hours, but some only last ~8 hours. Which ones lasts for 24 hrs?

Xyzal (levocetirizine) and Clarinex: From experience some of the newer antihistamines such as Xyzal (levocetirizine) and Clarinex seem to be effective for longer time periods. Most antihistamines however peak in effectiveness in the first few hours and start to wear off after 12-15 hours. ...Read more

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I am about to take an antihistamine for the first time but my friends tell me to use it before bedtime. Will I still feel the effects the next day?

Depends on the med: Some antihistamines are more sedating than others. Medications like Benadryl (diphenhydramine) can definitely cause sedation. Newer antihistamines like Allegra and Claritin are non-sedating and Zyrtec is sedating in roughly 10-20% of patients. ...Read more

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Is Flixonase an antihistamine?

Steroid Nasal Spray: Flixonase or Flonase (fluticasone proprionate) is a steroid nasal spray commonly used to treat allergic rhinitis by decreasing the allergic inflammation in the nasal mucosa. It is not an antihistamine. ...Read more

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Is there an antihistamine cream?

Is there an antihistamine cream?

Yes, but avoid: Benadryl (diphenhydramine) cream is available. While some people find temporary relief for insect bites with this, in general it is not very effective compared to other antihistamines taken as pills or tabs. For generalized rash, it really doesn't make sense. ...Read more

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What antihistamine has the strongest antiemetic properties?

Dramamine (dimenhydrinate): Dramamine (dimenhydrinate) and Meclizine are some that can be used. Different for different patients. ...Read more

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If someone takes 52 antihistamines, is this something to be concerned about?

Yes: It tells me that this is a risky behavior and likely a suicidal attempt. Call the psychiatrist or the suicide hotline. ...Read more

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Is Flonase an antihistamine?

Is Flonase an antihistamine?

No: Flonase is a nasal steroid spray. It is often used in conjunction with an antihistamine. The most commonly used antihistamines today are the non-sedating antihistamines: claritin, Allegra and zyrtec. Each of these had a generic drug available, too. ...Read more

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Which antihistamine for a rash?

Which antihistamine for a rash?

It depends on what: The rash is. If you have hives or an itchy rash - Benadryl (diphenhydramine) may be helpful. ...Read more

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I was wondering is antihistamine meant to burn?

No: Antihistamines are medications available as oral tablets, syrups or nasal sprays (Azelastine) to treat the symptoms of allergies. ...Read more

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What are non-sedative antihistamines?

The newer ones: Antihistamines can cause sedation by entering the brain's tissue and binding to h1 receptors. (called "crossing the blood brain barrier".) that effect is desirable if you are taking an antihistamine for sleep (e.g. Benadryl). The newer antihistamines don't cross the blood brain barrier as much. These include (least to most sedate) fexofenadine (allegra), Cetirizine (zyrtec), loratidine (claritin). ...Read more

Dr. Paul Carter
643 Doctors shared insights

Antihistamine (Definition)

Sedating and non-sedating antihistamines prevent and treat allergic reactions, and are ...Read more