What is Loratadine?

Mary McMahon
Mary McMahon

Loratadine is an antihistamine which is classically used to temporarily relieve the symptoms of hay fever, including runny nose, watery eyes, and skin irritation. This drug is available over the counter in many regions of the world, and in some areas, it is the only over the counter drug which is specifically useful for hay fever, making it a very popular product. As with all medications, it is a good idea to consult a doctor before using loratadine, to ensure that the drug will not conflict with an existing medication or health problem.

Blurred vision is among the side effects of Loratadine.
Blurred vision is among the side effects of Loratadine.

This drug was developed by Schering-Plough and it was originally marketed as Claritin. Some other trade names used to refer to loratadine include: Lorfast, AllergyX, Symphoral, Lomilan, Roletra, and Tidilor. It is also available as a generic. Initially, the drug was available by prescription only. However, when the drug went off-patent, it was approved for over the counter use, and patients can obtain the drug in the form of tablets, including fast-acting tablets, and syrup.

Loratadine can relieve hives.
Loratadine can relieve hives.

Common side effects include drowsiness, dizziness, and dry mouth. People can also develop blurred vision, gastrointestinal problems, confusion, depression, arrhythmias, and convulsions, although these side effects are more rare. Loratadine can interfere with allergy testing, and patients may be asked to abstain from using the drug for a week before an allergy testing session so that the results will not be skewed.

Loratadine is commonly used as a temporary treatment for hay fever.
Loratadine is commonly used as a temporary treatment for hay fever.

This drug may not be advised for people with liver and kidney problems, or it may be necessary to reduce the dosage of the drug for safety. Individuals with epilepsy have also experienced unfavorable side effects on loratadine, and the safety of the drug for use in breastfeeding and pregnancy should be discussed with a doctor.

Certain medications can cross-react with loratadine. For this reason, it is a good idea to discuss the drug with a primary care provider or pharmacist, and to disclose all medications and drugs which are being used, including herbal medications, so that the doctor can confirm that loratadine will be safe for use.

It is important to be aware that this allergy medication cannot prevent serious allergic reactions such as anaphylactic shock. The drug will also not cure hives, although it can reduce the itching, swelling, and redness associated with hives. Patients should be careful about mixing medications, and until they know how they react to loratadine, they may want to avoid operating heavy machinery, driving, or committing to social engagements, in case the drug makes them feel drowsy or dizzy.

Patients should be careful about mixing different prescriptions until they know how they will react to Loratadine.
Patients should be careful about mixing different prescriptions until they know how they will react to Loratadine.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


Did you know your body can become immune to the effects of allergy medications over time? This happened to me after taking loratadine for two years, and I had to switch for awhile.

I told my doctor that my allergies had returned, and she told me that I needed to switch up my medications occasionally in order for them to maintain their effectiveness in my system. So, I switched to cetirizine hydrochloride for six months, and my symptoms cleared up.

Once the six months were up, I switched back to loratadine. It worked as wonderfully as it had in the beginning.


@cloudel - I had the same issue with loratadine as you, but I discovered a way to get around the problem. Since I take most of my other medications at night, I started taking loratadine right before bed, also.

I found that in addition to staying awake and sniffle-free the next day, I also fell asleep sooner and slept more soundly. This drug should be marketed as a sleeping pill!

I feel your pain. I could not have continued taking it if I had to do so in the morning, because I could not function. My brain was cloudy, and my body slowed down. I hope taking it at night works as well for you as it did for me.


Loratadine does a better job at stopping my allergy symptoms than anything else I have tried. I have one issue with it, however.

It makes me so sleepy that I can hardly stay awake! Driving to work is difficult, but staying conscious at my desk is even harder.

I feel miserable being this sleepy, but I also feel terrible sniffing and sneezing all day without the drug. Does anyone know of anything I can do to keep taking it but stay alert at the same time?


I decided to try loratadine after my sister raved about it. She works in a veterinary clinic, and it helped her with her allergy problems, even though she is exposed to cat and dog hair on a daily basis.

After the first day of trying it, I was amazed at how well it worked. A few days later, though, I started having intestinal cramps. It felt like I had trapped gas, and it was pretty painful.

I had to stop taking loratadine, but I did find another antihistamine that worked for me. It’s a shame though, because it doesn’t work as well as loratadine.


I just wanted to mention that I take loratadine, and I don't notice a difference when I take the store brand versus the name brand. The active ingredient is exactly the same! Check the bottles!

The biggest difference is really the price. And if you're trying to be conscientious about you're budget, using store brand medicine is a good place to start.


@JessicaLynn - Some of the supposed non-drowsy allergy medicines do make me drowsy. I took Zyrtec briefly and it made me so sleepy. I ended up switching to loratadine, which I'm fine with.

I have a lot of allergies too, and I keep meaning to go get allergy testes. However, I don't think I can go for a week without taking my medicine! I think I'm going to have to wait until the dead of winter one year and make sure my house is really, really clean. It stinks that allergy medicine can interfere with allergy testing!


You know, it's funny that loratadine can make you drowsy. Because it's marketed as a non-drowsy anti-histamine! I'm pretty sure some of the other "non-drowsy" anti-histamines can cause drowsiness also.

I take an anti-histamine on a regular basis, and luckily it doesn't make me drowsy because I really need to take it. I have a ton of allergies.

I have to say, too, that I'm extremely happy that drugs like Claritin and Allegra are available over the counter now. I used to pay twice as much for my medicine when it was prescription only!

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