Loratadine side effects and how to avoid them

Common loratadine side effects | Serious side effects | Heart palpitations | Weight gain | Drowsiness | Anxiety | Side effects timeline | Contraindications | Warnings | Interactions | How to avoid side effects | How to treat side effects

Loratadine is the generic version of Claritin and other brand-name allergy relief products such as Alavert. Loratadine relieves symptoms caused by upper respiratory allergies including hay fever: runny nose (allergic rhinitis), itchy eyes, watery eyes, sneezing, or sore throat. It can also be used for hives (urticaria), itchy skin, or insect bite reactions. Loratadine is a second-generation or non-drowsy antihistamine. Like Benadryl (diphenhydramine), loratadine prevents histamines, which are released in response to allergens, from causing swelling and other symptoms. It does not, however, easily enter the brain, so it’s less likely to cause the sleepiness and dizziness associated with other antihistamines. That doesn’t mean it’s free of side effects. However, most side effects are mild and interfere little with daily functioning. 

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Common side effects of loratadine

Headaches are the most commonly experienced side effect of loratadine. Other common side effects include:

• Drowsiness
• Fatigue
• Diarrhea
• Ear pain
• Sore throat
• Dry mouth
• Nose bleeds
• Skin rash
• Stomach pain

Serious side effects of loratadine

The most serious side effects of loratadine include:

• Airway closure (bronchospasm)
• Fainting
• Seizures
• Low platelet counts
• Liver problems
• Severe allergic reactions

Heart palpitations 

There are cases of non-drowsy antihistamines provoking heartbeat irregularities. The incidence is estimated to be very low, about one in every 57,000 people. However, loratadine is frequently combined with a decongestant. Claritin-D, for instance, contains both loratadine and pseudoephedrine. Decongestants can cause heart problems like palpitations or racing heartbeats. Contact a healthcare provider if you experience fast or irregular heartbeats.

Weight gain

Studies have shown that prescription antihistamines are associated with weight gain. In fact, at least one antihistamine is prescribed off-label to help people with anorexia nervosa gain weight. Weight gain is a long-term side effect, so it’s associated more with prescription antihistamines or the chronic use of nonprescription antihistamines. The drug has to be taken regularly for weeks or months for weight gain to become obvious. Loratadine is not as strongly associated with weight gain as some other antihistamines such as Benadryl, but that’s partly because it’s less likely to be used regularly as a sleep aid or another off-label purpose. If unwanted weight gain is experienced when taking any antihistamine, get medical advice from a healthcare professional.

Drowsiness

As a non-drowsy antihistamine, loratadine is less likely to cause drowsiness than Benadryl, which contains a first-generation antihistamine called diphenhydramine. That doesn’t mean that drowsiness is not a possible side effect of loratadine. While the incidence of drowsiness is 22% among people taking diphenhydramine, it’s around 8% among people taking loratadine – that’s an improvement, but still one out of 12. “Less-drowsy” is probably a more accurate description than “non-drowsy.” The drowsiness may not be as severe or frequent as with other antihistamines, but it can be anticipated and planned for. If drowsiness is too severe, stop taking loratadine, try a different non-drowsy antihistamine, or get medical advice from a healthcare professional about other treatment options.

Anxiety

Anxiety is a reported side effect of loratadine, but the incidence is unknown. Loratadine does have sedating effects—the opposite of anxiety—so anxiety is considered an unlikely side effect. On the other hand, many loratadine products such as Claritin D are combination drugs that include decongestants like pseudoephedrine. Decongestants are stimulants. They excite the central nervous system, so anxiety, restlessness, nervousness, and physical symptoms of anxiety such as high blood pressure and racing heartbeats are commonly experienced. If loratadine seems to be causing anxiety, check the active ingredients list. Consider switching to a loratadine product without a decongestant. If the product being used only contains loratadine, switch to a different non-drowsy antihistamine such as cetirizine.

How soon do loratadine side effects start?

Loratadine begins to show effects one to three hours after a dose is taken. These effects peak in about eight hours. Allergic reactions and racing heartbeats could manifest soon after the first dose. Many common side effects such as headache, drowsiness, and diarrhea begin early, as well. Some side effects, however, are delayed, such as weight gain or liver problems. 

How long do loratadine side effects last?

Over-the-counter loratadine should only be used when allergy symptoms are a problem. Most side effects will go away when loratadine is stopped. A single dose can be effective for up to 24 hours, so wait about a day after taking the last dose to see side effects improve. 

What are the long-term side effects of loratadine?

Loratadine and other antihistamines should not be used long-term except under the supervision of a healthcare professional. Some of the most serious side effects of loratadine require daily use over weeks and months to become a problem. Though rare, delayed side effects include seizures, liver problems, blood clotting problems, constipation, and weight gain. 

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Loratadine contraindications

People who have had an allergic reaction to loratadine or a similar drug, desloratadine, should never take loratadine products.

Pregnancy

Loratadine is considered an acceptable antihistamine to use during pregnancy but it’s not recommended during the first trimester. Based on limited research, there is no evidence that loratadine can harm a fetus.

RELATED: Your guide to taking allergy medicine while pregnant

Breastfeeding

Loratadine is considered safe to take when breastfeeding. It is present in human breast milk, but studies on breastfed infants have shown only minor and rarely experienced problems such as sleepiness in nursing infants. Women who are breastfeeding, however, should consult with a healthcare professional before taking loratadine. Low doses may be advised.

Children

The FDA has determined that loratadine is safe and effective in children 2 years of age and older. Very young children (5 years of age or younger) should only receive half the adult dose, so use a children’s formulation.

RELATED: Treating seasonal allergies in teens, kids, and toddlers

Loratadine warnings

Although loratadine can be used without a prescription, that doesn’t mean it’s perfectly safe for everyone. There are a few issues that consumers should be aware of.

Cautions

Some people with pre-existing medical conditions cannot break down or eliminate loratadine from the body as well as others. These include people with liver disease or moderate to severe kidney disease. 

People with phenylketonuria (PKU), a rare congenital disorder, may not be able to take some loratadine orally disintegrating tablets because they may contain phenylalanine.

Abuse

Loratadine is not considered a drug likely to be abused or to cause physical dependence or withdrawal. However, loratadine products that include pseudoephedrine are a different matter. Pseudoephedrine is a widely abused drug. In some locations, products containing pseudoephedrine may be sold only as “behind-the-counter” products, that is, not available for open sale. The loratadine in these products, however, is not a concern. 

Overdose

Call a poison control center or get medical attention if too much loratadine is taken. Symptoms may include drowsiness and headaches. An overdose is usually not harmful unless very large amounts are taken or other drugs are included in the overdose. In those cases, get emergency medical care. 

Loratadine

Although loratadine itself has not been taken completely off the market at any time, individual manufacturers have sporadically recalled loratadine products because of quality issues.

Loratadine interactions

Loratadine has been used since 1988. Since that time, no significant drug interactions have been discovered involving prescription drugs, over-the-counter medications, or dietary supplements. That being said, some people will experience drowsiness when taking loratadine. Though usually mild, other drugs that depress the central nervous system may worsen drowsiness. These include other antihistamines and alcohol.

Drug interactions are possible with other drugs like decongestants used in loratadine allergy relief products. To avoid problems, it’s important to read the active ingredients list of any store-bought medicine and research the side effects and drug interactions of all the drugs in the medicine.

How to avoid loratadine side effects

As an over-the-counter medication, loratadine is intended for self-medication. It’s generally safe but may sometimes cause problems. They’re usually mild problems, but there are a few ways to minimize or prevent them from occurring.

1. Follow the directions

Follow the directions written on the box or the drug information sheet packaged in the box. Do not exceed the recommended dose. Do not take extra medicine unless instructed to by a healthcare professional. Adults can take up to 10 mg per day; very young children can take up to 5 mg per day.

2. Take only one dose of loratadine per day

Taking too much loratadine will increase the likelihood of side effects. Loratadine is only intended to be taken once per day. Always take the next dose the day after. 

3. Read the list of active ingredients

Make sure to know all the drugs contained in many store-bought allergy relief products. Often, allergy relief pills will have more than one drug packed into each pill. These other drugs all have their own side effects and drug interactions. Read the list of active ingredients and look up possible side effects and drug interactions. Above all, don’t take other drugs containing the same or a similar drug. For instance, don’t combine Claritin D, which contains an antihistamine combined with pseudoephedrine, with a drug like Sudafed, which also contains pseudoephedrine, or Tylenol PM, which contains an antihistamine. 

4. Talk to a healthcare provider

People with liver problems, kidney problems, or who are pregnant or breastfeeding should talk to a healthcare professional before taking loratadine. People with liver or kidney dysfunction may need to take smaller doses.

How to treat side effects of loratadine

Loratadine’s side effects are mild. Most can be helped with a few simple tips.

Drowsiness

The best way to handle drowsiness is to take it easy. Sit down, lie down, and wait it out. Don’t try to drive, operate machinery, or do risky activities like chopping food or skiing. Drowsiness itself is not dangerous. However, falling, suffering accidents, and getting injured—all the things that can happen when someone is drowsy—are dangerous. If drowsiness is a serious problem, talk to a healthcare provider about other treatment options.

Headache

Drink plenty of fluids and take it easy. Over-the-counter pain relievers are okay to use, but it’s a good idea to talk to a healthcare provider first. If headaches persist, get medical advice.

Allergic reactions

Loratadine can cause a serious and even life-threatening allergic reaction called anaphylaxis. An allergic reaction means it’s time to stop taking the drug and get immediate medical attention. Symptoms include:

• Hives
• Swelling of the face, mouth, lips, tongue, or throat
• Trouble breathing
• Wheezing
• Lightheadedness
• Racing heartbeats
• Cold and clammy skin
• Confusion
• Fainting