Question 1

what is the reason behind 1st generation antihistamine induce sleep ( by which mechanism cause sleepiness in our brain ) ?

Accepted Answer

Anticholinergic: First generation antihistamines block the h1 and h2 histamine receptors but also have some anticholinergic effects by partially blocking other receptors. This can lead to dry mouth, urinary retention, sedation and other side effects. This is usually dose dependent and worsens with high doses.

Question 2

what causes paradoxical reactions to benadryl (diphenhydramine). what mechanism ocurrs in the brain that makes the person stimulated rather than drowsy?

Accepted Answer

Not entirely known: But you're describing a very real phenomenon. The same can happen with pain medicines and other sedatives too.

Question 3

what is the best otc antihistamine?

Accepted Answer

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.

Question 4

is antihistamine harmful to the body?

Accepted Answer

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.

Question 5

when should you take an antihistamine?

Accepted Answer

For allergies: Antihistamines help the most with sneezing, watery drainage, and itching which are often seen with allergies. Older antihistamines (like benadryl) can make people sleepy and should be used with caution; newer antihistamines (like Claritin (loratadine) & allegra) are less likely to be sedating. Because of their drying effect, some doctors recommend avoiding antihistamines during a respiratory infection.

Question 6

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

Accepted Answer

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

Question 7

is flixonase an antihistamine?

Accepted Answer

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.

Question 8

is there an antihistamine cream?

Accepted Answer

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.

Question 9

does antihistamine make you drowsy?

Accepted Answer

Older ones do: First generation antihistamines (benadryl, clor-pheramine, atarax) cross the blood brain barrier and cause lethargy.  
Second generation (allegra, claritin, zyrtec, xyzal, (levocetirizine) clarinex) cause the blood brain barrier at a much lesser amount and more targeted to the h1 receptor.

Question 10

can you use antihistamine and wine?

Accepted Answer

Not a good idea: Antihistamines (especially the older ones such as benadryl) can cause drowsiness and impairment and this can be worsened by the effect of alcohol even at regular doses.  There are other allergy medications available that can be taken if a glass of wine is desired.

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Antihistamine mechanism of action

A member asked:

What is the reason behind 1st generation antihistamine induce sleep ( by which mechanism cause sleepiness in our brain ) ?

A member asked:

What causes paradoxical reactions to benadryl (diphenhydramine). what mechanism ocurrs in the brain that makes the person stimulated rather than drowsy?

A member asked:

What is the best otc antihistamine?

A member asked:

Is antihistamine harmful to the body?

A member asked:

When should you take an antihistamine?

A member asked:

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

A member asked:

Is flixonase an antihistamine?

A member asked:

Is there an antihistamine cream?

A member asked:

Does antihistamine make you drowsy?

A member asked:

Can you use antihistamine and wine?

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