Like all medicines, antihistamines can cause side effects.
We take 10 mg because effectiveness is not significantly different between 10 mg and 40mg. Read more From experience some of the newer antihistamines such as Xyzal (levocetirizine) and Clarinex seem to be effective for longer time periods.If by allergic reaction you are referring to seasonal allergies, the gold-standard therapy is daily nasal steroid sprays and/or antihistamine nasal sprays. Read more 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. 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.Nasal saline rinses, avoidance measures, and if refractory to treatment, allergy shots can also be helpful. For generalized rash, it really doesn't make sense. Read more First generation antihistamines (benadryl, clor-pheramine, atarax) cross the blood brain barrier and cause lethargy.An antihistamine injection, usually diphenhydramine, sometimes given for a severe allergic reaction or anaphylaxis begins to work in a few minutes. Read more Safety of high dose medications is often unknown.Our experience comes from case reports of persons who intentionally or accidentally consumed unusually excessive quantities.Most antihistamines however peak in effectiveness in the first few hours and start to wear off after 12-15 hours. Read more Some antihistamines are more sedating than others.Medications like Benadryl (diphenhydramine) can definitely cause sedation.These include (least to most sedate) fexofenadine (allegra), Cetirizine (zyrtec), loratidine (claritin). Read more The second generation zyrtec, allergra or Claritin (loratadine) are comparative. Zyrtec is slightly more likely to make you tired ot sleepy. New generation products (Zyrtec, Claritin, (loratadine) Allegra, Xyzal) are just as effective with less side effects than older antihistamines (Benadryl, chlorpheniramine, hydroxyzine).Often one works a little better than another and I adise you to test all three. Read more Antihistamines are a class of medication used since the 1940s. Are you considering taking an overdose of antihistamines? 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). However, it would be important to address WHY a person needs to take antihistamines long term?Newer antihistamines like Allegra and Claritin are non-sedating and Zyrtec is sedating in roughly 10-20% of patients. Read more Although not necessarily the main treatment option in eczema, the use of antihistamines to calm down the itch associated with eczema seems to help quite a bit.Remember that eczema is the itch that rashes, the more you scratch the worse it is. Read more Antihistamines can be taking twice a day safely if required but there are other treatments available. Read more Benadryl (diphenhydramine) cream is available.