This time of year, allergy-medicine aisles see a steady stream of sniffling souls turning over box after box to figure out which of the million medications will give them the best relief.
Despite their varied names and colorful labels, most of these boxes boast similar claims: They’ll fix your sneezing, itchy eyes, and runny nose. That’s because most of them contain one form or another of the same type of drug: an antihistamine.
Antihistamines are the go-to medicine for most people with seasonal allergies. The different types of antihistamines all work in a similar way. Which type works best for you depends on a few factors, including simply which one your own unique body prefers.
What Symptoms Do Antihistamines Treat?
If you read part one of my allergy-medicine series, you know histamine is what causes most of your seasonal allergy symptoms. Antihistamines prevent histamine from being released, and thus prevent the symptoms it causes: mainly sneezing, watery eyes, runny nose, and itching. Antihistamines can also help make you feel better overall and may fight a bit of a stuffy nose. (Decongestants are better for that; I’ll cover those next week.)
If you have bad seasonal allergies, consider starting an antihistamine at the first sign of symptoms or earlier so the histamine doesn’t have time to set up a big, strong shop.
Which Antihistamine Is Best?
There are different subclasses and generations of antihistamines, so if one doesn’t work well for you, try another. In theory, they all work about equally well, but if you do a little trial and error, you’ll find one that does the best job for you.
Here are some of the most common options:
- First-generation antihistamines: These were the first ones developed. The most common problem is drowsiness. Diphenhydramine (Benadryl) is in one subclass. Chlorpheniramine (Chlor-Trimeton) and brompheniramine (Dimetapp) are in a different one.
- Second-generation: These were created to cause less drowsiness, but they still can make some people sleepy. Examples in one subclass are loratadine (Alavert, Claritin) and fexofenadine (Allegra). Cetirizine (Zyrtec) is in another.
- Third-generation: These are supposed to cause even fewer side effects than the second-generation ones. At present, they’re kind of vaguely defined and usually just more refined derivatives of the second-generation antihistamines. Right now they’re prescription only, and time will tell which ones might truly have significant advantages compared to their increased cost.
In general, antihistamines start working on your allergies a couple of hours after you take them. The second-generation ones last long enough that you don’t have to take them but once a day. Surprisingly, at least to me, they still start acting as early as or earlier than the first generation.
Where Else Do You Find Antihistamines?
Antihistamines aren’t only used to treat allergies. Some classes treat nausea, stomach acid, and other medical problems.
Allergy-related antihistamines are in some of the more common sleeping pills. Cold and flu medicines usually have an antihistamine too. (Although, antihistamines actually don’t help a lot with viral symptoms, other than drying you up a little. A decongestant and pain reliever are often the better choice.)
Antihistamines can also be used to fight skin allergic reactions (urticaria). And for any type of anaphylactic reaction, you may want to take an antihistamine in addition to using an EpiPen. (Antihistamines are too slow to be a first-line defense. You might be dead before they kick in. But they can help in addition to the EpiPen.)
What About Antihistamine Eye Drops and Nose Sprays?
If your only symptom is itchy, watery eyes, antihistamine eye drops, which are available over-the-counter, will go straight to that problem.
Currently, the nasal spray antihistamines are only available with a prescription. Like the eye drops, these treat the specific problem at its source (an itchy, runny nose), and they don’t circulate through the body as much as oral medications.
What Are Your Best Tips for Taking Antihistamines?
If you have mild symptoms, you might get by with taking antihistamines as needed. But most people do better taking them on a daily basis through the worst of the allergy season. That way, the antihistamine builds up to maximum strength in their system and can better stay ahead of the mast cells (which release histamine).
What Are Some Common Precautions?
Always read the interactions, side effects, and precautions of any medication before taking it. Besides drowsiness, a couple of the most common side effects of antihistamines are dry mouth and blurred vision.
Don’t take antihistamines if you have a bladder problem or any difficulty urinating. It can cause trouble with urination, especially in men with an enlarged prostate (but also in some women).
Check with your doctor before taking antihistamines if you’re pregnant or breastfeeding or if you have certain medical conditions, including:
- Glaucoma. Antihistamines make some types worse.
- Breathing problems, such as asthma, emphysema, or chronic bronchitis. Antihistamines may dry out the mucus lining too much.
- Thyroid disease.
- Heart disease.
- High blood pressure.
What About Combination Medicines?
Some allergy medicines contain only an antihistamine; others have additional drugs, such as decongestants or pain medicines. Only choose a combination medicine if you need it—for example, if you have sneezing and a stopped up nose (and therefore want a decongestant with the antihistamine). Each type of medicine you take brings its own risk of side effects. You might as well not take a catch-all med if your main problem is just sneezing.
But if antihistamines aren’t working for you, combination medicines or even other options you may be less familiar with may work better. I’ll cover those next week.
Do you take antihistamines? Do you take them as needed or continuously throughout your allergy season?
This has been part 2 of my seasonal allergy series. Click here for part 1, about how allergies work. Subscribe below to make sure you don’t miss part 3: additional allergy medicines that may help you even more.
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