Xyzal vs Benadryl – Compare Differences Between Uses & Side Effects


It is the brand name of a drug called levocetirizine, a third-generation non-sedating antihistamine that is developed from the second-generation antihistamine cetirizine.

This medication works by blocking the action of histamine, a neurotransmitter in the human body that is produced by the body when it reacts to a foreign substance, like –  pet fur or pollen.

This substance acts on histamine receptors, leading to a chain reaction that results in allergic symptoms.


It treats allergy symptoms, like – swelling, itching, and rashes.


The usual recommended dose for adults and children 12 years of age and older is 5 mg once per day in the evening. The effect of this antihistamine lasts for an average of 24 hours.

Note – seniors should use this medication with caution since they may be more sensitive to its effects.

Side Effects and Precautions

Common side effects may include:

  • feeling tired;
  • weakness;
  • drowsiness;
  • a cough;
  • fever (high temperature);
  • a sore throat;
  • sinus pain;
  • stuffy nose.

Rare side effects may include:

  • lightheadedness;
  • agitation;
  • nosebleeds (particularly in a child);
  • hallucinations;
  • worsening allergy symptoms;
  • hearing problems;
  • little or no urinating;
  • dark-colored urine;
  • depression;
  • foul-smelling stools;
  • drainage from the ear;
  • aggression;
  • painful or difficult urination;
  • loss of appetite;
  • ear pain or full feeling;
  • tingling around the lips or mouth;
  • yellowing of the skin or eyes (jaundice);
  • ear infection;
  • a light-headed feeling like you might pass out;
  • stomach pain;
  • dry mouth;
  • constipation;
  • trouble hearing;
  • unexplained weight gain;
  • vomiting.


This antihistamine can pass into breast milk and may harm the infant. Therefore, you shouldn’t breastfeed while taking the medication. In addition, it is a Pregnancy Category B drug, which means it is not expected to harm an unborn baby.

Drug Interactions

Tell your healthcare provider about all the medications you take, including non-prescription and prescription medicines, herbal supplements, and vitamins. Especially tell your healthcare provider if you take:

  • cimetidine (Tagamet);
  • antidepressants;
  • Miralax;
  • sedative or sleeping pills;
  • ritonavir (Norvir);
  • antipyrine (Aurodex, Phenazone, Auroto);
  • pseudoephedrine (Sudafed);
  • azithromycin (Zmax, Zithromax);
  • theophylline (Slo-Bid, Theolair);
  • antihistamines (doxylamine succinate);
  • medications for mental illness, anxiety (Zoloft), or seizures;
  • ketoconazole (Nizoral);
  • erythromycin (Erythrocin).


It is the brand name of a drug called diphenhydramine which belongs to a group of drugs called antihistamines.

This antihistamine is easily absorbed when taken by mouth. It acts on cells in the brain and reduces the activity of a chemical messenger in the brain called histamine as well as acetylcholine (a neurotransmitter at neuromuscular junctions).

This medication was originally approved by the US Food and Drug Administration in 1946. It is manufactured by Johnson & Johnson subsidiary McNeil Consumer Healthcare.


It is used to treat motion sickness, to suppress coughs, and sometimes, to treat mild forms of Parkinson’s disease.

Also, this antihistamine is used to treat a runny nose, sneezing, hives, watery eyes, rashes, and other symptoms of the common cold and allergies.

Moreover, it may decrease the time before you fall asleep, therefore, it is used to temporarily relieve sleep disturbances (insomnia).


The usual recommended dose for adults is 25 to 50 mg at bedtime. Maximal action happens about 60 minutes after intaking the medication. Its effects continue for 4 to 6 hours.

Note – it shouldn’t be used for infants below 2 years since they don’t produce histamine in much quantity, hence, it can affect their brain (histamine is also a neurotransmitter involved in regulating physiological function as well as local immune responses).

Store this antihistamine at room temperature and keep it out of the reach of children.

Side Effects and Precautions

Common side effects may include:

  • heartburn;
  • dizziness;
  • dry mouth;
  • a difficulty with coordination;
  • vertigo;
  • thickened chest mucus;
  • stuffy nose;
  • sun sensitivity;
  • tremors;
  • loss of appetite;
  • early menstrual period;
  • constipation or diarrhea;
  • changes in mood, like – euphoria, excitability, nervousness, and irritability;
  • tingling or numbness;

Rare side effects may include:

  • swelling of the face or throat;
  • rash or hives;
  • tightness in the chest;
  • itchiness;
  • heart palpitations;
  • low blood pressure;
  • worsening of existing conditions, like – ulcers, glaucoma, or gastroesophageal reflux disease;
  • anemia;
  • irregular or rapid heartbeat;
  • trouble passing urine;
  • confusion;
  • hallucinations;
  • low blood platelets;
  • seizures;
  • vision changes, like – double vision or blurriness.

Talk to your healthcare provider before taking this antihistamine if you have any of these conditions:

  • eye problems;
  • asthma;
  • heart disease;
  • emphysema (a long-term lung disease);
  • overactive thyroid;
  • seizures;
  • hypertension;
  • difficulty passing urine;
  • chronic bronchitis.


This medication can pass into breast milk and may negatively affect the infant, therefore, avoid it if you are breastfeeding.

There are no conclusive clinical studies regarding the safe use of this antihistamine during pregnancy, thus, ask your healthcare professional before using this medicine if you are pregnant or plan to get pregnant.


It is generally recommended to avoid the use of alcohol while taking this antihistamine since it will increase the risk of side effects.

Bottom Line – Xyzal vs Benadryl    

Xyzal (active ingredient – levocetirizine) is a third-generation antihistamine that reduces the effects of histamine in the human body. Histamine can produce symptoms of itching, sneezing, runny nose, and watery eyes.

The medication is also called a non-drowsy or non-sedating antihistamine since it doesn’t enter the brain in substantial amounts, therefore, it is unlikely to cause drowsiness. In addition, it is similar to Zyrtec, hence, if you can’t take Zyrtec, you won’t be able to take levocetirizine.

The usual recommended initial dose for children and adults is 5 mg once a day in the evening.

Benadryl (active ingredient – diphenhydramine hydrochloride) is a first-generation antihistamine drug with anticholinergic and sedative effects.

Due to the fact that is a first-generation antihistamine, it actually means that it was one of the first antihistamines developed. More importantly, it means that it has more side effects than the later generations of antihistamines, especially drowsiness.

Additionally, according to a 2014 study issued in the International Journal of Psychiatry in Clinical Practice, first-generation antihistamines are linked with increased anxiety, depression, and fatigue scores than the newer-generation medications.

Image credit – Shutterstock

READ THIS NEXT: Temazepam vs Ambien For Sleep


Leave a Comment