Difference Between Zyrtec (Cetirizine) and Claritin (Loratadine)

Zyrtec and Claritin are very popular drugs and frequently prescribed allergy medicine. They both come under the drug class second generation antihistamine drugs. The mechanism of action is to effect the histamine action inside the body; histamine is the chemical responsible for allergy response.


Zyrtec is better known by its generic name Cetirizine and other trade names like “All day allergy” and Indoor/Outdoor allergy relief. This is used to treat allergic responses such as sneezing, watery nose, itching nose and throat etc. A person, while under medication, should not attend to work that requires being in alert as the drug tend to impair thinking and reacting. Alcohol should be strictly avoided because it increases the intensity of side effects.

Side effects such as uneven heart rate, insomnia, tremors, restlessness, confusion, blurred vision, dizziness, tired feeling, dry mouth, cough, constipation, nausea, less urination etc. are frequently associated with Zyrtec use. Some drugs such as other allergy medicine, narcotic pain medicine, muscle relaxers, seizure medicine, sleeping tablets should not be administered simultaneously because they can add to the sleepiness. Zyrtec has not shown any harmful effects to the unborn baby if taken during pregnancy but it has shown to harm the nursing baby if taken by a breast-feeding mother.


Claritin, known by other trade names Alavert, Loratadine Reditab, Tavist ND etc., stands for the same drug known by the generic name Loratadine. This drug is actually an antihistamine drug. What it does is, reduce the effects of histamine that is naturally synthesized in our bodies. Histamine is the chemical responsible for allergy symptoms such as sneezing, watery nose, itching nose and throat etc. This medicine is also used to treat skin hives.

Claritin should not be taken if one is either allergic to the medicine or has a history of kidney disease or liver disease. This medicine is harmful to children below six years and should not be administered under any circumstances because for some the effects could be even deadly. Claritin has not shown any harmful effects to unborn, but since it passes through breast milk may possibly harm a nursing baby. The drug is available as a pill and syrup. It is important that the dosage is followed exactly as prescribed. In an incident of overdose a person may experience increased heart rate, drowsiness and headache.

There are many serious and minor side effects associated with Claritin. Among serious side effects, convulsions, jaundice, increased heart rate, and feeling of “passing out” are the main, side effects and minor side effects such as diarrhea, drowsiness, blurred vision etc. may also be present. Some drugs can contain amounts of antihistamine medicine; therefore, a doctor’s advice should be taken when other drugs are taken simultaneously. Especially vitamins, minerals and herbal products should be only consumed with doctor’s approval.

What is the difference between Zyrtec and Claritin?

• Zyrtec is more frequently prescribed or purchased than Claritin.

• Among the forms of the drug, Zyrtec has an additional form of eye drop medicine which Claritin does not have.