Singulair vs Zyrtec

Singulair vs Zyrtec
Woman watching a laptop screen while stretching her hand and typing on it

Many readers are interested in the following topic: Singulair vs Zyrtec. We are happy to note, that our authors have already studied the modern research about the topic you are interested in. Based on the information provided in the latest medical digests, modern research and surveys, we provide extensive answer. Keep reading to find out more.

Allergic rhinitis is a medical condition that is caused by an allergy to substances breathed in the air.


Symptoms may include:

  • clear drainage from the nose;
  • sneezing;
  • nosebleeds;
  • congestion;
  • itchy nose, eyes, throat, and ears;
  • a runny nose.


The most common causes include the following:

  • tobacco smoke;
  • pollen (grass, tree, weed);
  • animal dander;
  • dust mites;
  • cockroach droppings;
  • mold.


Treatment options include medications like:

  • decongestant nasal sprays or tablets;
  • saline nasal sprays;
  • non-sedating antihistamines;
  • intranasal corticosteroid sprays.

Here is a comparison between two medications that are used in the treatment of allergic rhinitis:


It contains the active ingredient montelukast, a leukotriene inhibitor. It is indicated for:

  • the relief of symptoms of perennial allergic rhinitis in patients 6 months of age and older;
  • the relief of symptoms of seasonal allergic rhinitis in patients 2 years of age and older;
  • the prevention of exercise-induced bronchoconstriction in sufferers 6 years of age and older;
  • the prophylaxis and chronic treatment of asthma in adults and pediatric patients 12 months of age and older.

Asthma is a lung disease and has the following characteristics:

  • sensitive airways which react to pollen, cigarette smoke, or cold air;
  • inflamed airways, which means the lining of airways become swollen;
  • narrowed airways causing breathing to become substantially harder.

Important note – this medication is not used to treat an acute attack of asthma.

If you are experiencing an acute asthma attack, it is recommended to follow your healthcare provider’s instructions for your reliever medicine.


It contains the active ingredient cetirizine, an antihistamine that belongs to the family of drugs referred to as second-generation antihistamines.

It comes in the form of chewable tablets, tablets, and syrup and is produced by McNeil-PPC, Inc.

The medication is approved for the treatment of:

  • allergic rhinitis (hayfever);
  • urticaria (hives).

Mechanism of Action


Montelukast works by inhibiting the cysteinyl leukotriene CysLT1 receptor. It either reduces or prevents:

  • muscle contractions in the airways;
  • asthma symptoms;
  • redness and inflammation in the airways.


This antihistamine works by reducing the effects of histamine in the body.

Side Effects

Possible side effects of Singulair include:

  • trouble breathing;
  • headache;
  • sore throat;
  • diarrhea;
  • cough;
  • nausea;
  • ear infection;
  • upset stomach;
  • muscle weakness;
  • heartburn;
  • skin rash;
  • stomach pain;
  • shaking;
  • tooth pain;
  • tremors;
  • tired feeling;
  • worsening asthma symptoms;
  • dizziness;
  • severe dizziness;
  • hoarseness;
  • severe sinus swelling, pain, or irritation;
  • fever;
  • swelling of the face, tongue, or throat;
  • mild rash;
  • hives;
  • upper respiratory infection;
  • purple or red pinpoint spots under your skin;
  • an earache;
  • unusual bleeding (nose, vagina, mouth, or rectum);
  • thoughts about suicide or hurting yourself;
  • easy bruising;
  • depression;
  • anxiety;
  • mood changes.

Possible side effects of Zyrtec include:

  • confusion;
  • fast or uneven heartbeat;
  • little or no urination;
  • sleep problems (insomnia);
  • drowsiness;
  • tremors (uncontrolled shaking);
  • tired feeling;
  • weakness;
  • dry mouth;
  • hyperactivity;
  • constipation;
  • severe restless feeling;
  • nausea;
  • dizziness;
  • problems with vision.


For allergic or perennial rhinitis, the usual recommended dose of Singulair is 10 mg once per day.

For allergic rhinitis, the usual recommended dose of Zyrtec is 5 to 10 mg orally once per day.

The maximum recommended dosage in a 24-hour period is 10 mg.

Warnings and Precautions


Avoid this medication if you have an inherited condition in which a diet must be followed, called phenylketonuria.

This condition is s caused by a defect in the gene which helps produce the enzyme required to break down phenylalanine.

In addition, tell your healthcare provider if you are allergic to any ingredients of this medication.


Tell your healthcare professional if you use other medicines which make you sleepy since Zyrtec can make you sleepy as well.

These medicines can include:

  • medicines for depression, seizures, or anxiety;
  • muscle relaxers;
  • sleeping pills;
  • narcotic pain medicines;
  • cold or allergy medicines.

Moreover, this antihistamine may impair your reactions or thinking, therefore, be careful when engaging in activities that require you to be alert.

Drug Interactions

Singulair may interact in a negative way with the following medications:

  • irbesartan (an angiotensin II receptor antagonist which is used mainly for the treatment of hypertension);
  • bosentan;
  • mifepristone;
  • capecitabine (a chemotherapy medication that is used to treat gastric, colorectal, or breast cancer);
  • mitotane;
  • ciprodex;
  • carbamazepine (a medication that is used in the treatment of epilepsy);
  • oxcarbazepine;
  • dabrafenib;
  • peginterferon Alfa-2b;
  • fenofibric acid;
  • primidone;
  • fluconazole;
  • tolbutamide;
  • clindamycin;
  • fluorouracil (a medication used to treat cancer);
  • zafirlukast;
  • leflunomide;
  • trimethoprim;
  • losartan (a medication mainly used to treat high blood pressure);
  • rifabutin;
  • omeprazole (a medication used in the treatment of gastroesophageal reflux disease);
  • quinine (a medication used to treat babesiosis and malaria);
  • delsym;
  • phenytoin.

Zyrtec may interact in a negative way with the following medications:

  • Xanax (alprazolam);
  • Benadryl (diphenhydramine);
  • trazodone (a medication that is used to treat the major depressive disorder);
  • Cymbalta (duloxetine);
  • gabapentin;
  • tramadol.


Avoid consuming alcoholic beverages while taking these medications since alcohol can make side effects like dizziness significantly worse.

Is It Safe During Pregnancy or Breastfeeding?

It is not known whether these medications pass into breast milk.

Talk to your doctor prior to use if you are breastfeeding a baby.

Also, tell your doctor if you are pregnant since there are no studies regarding the use of these medications while being pregnant.

Bottom Line – Singulair vs Zyrtec

Singulair contains montelukast – a drug that belongs to a class of medications called leukotriene receptor antagonists (LTRAs). It can be used:

  • in the treatment of atopic dermatitis (a type of eczema);
  • in the treatment of allergic rhinitis;
  • in the prevention of exercise-induced asthma;
  • adjunctive therapy in combination with inhaled steroids for the treatment of asthma;
  • a therapy for the treatment of mild persistent asthma.

Zyrtec (cetirizine) is an over-the-counter antihistamine that is used to treat cold and allergy symptoms, like – itching, watery eyes, sneezing, or a runny nose.

A 2004 study that compared the efficacy and safety of montelukast and cetirizine for the treatment of pediatric perennial allergic rhinitis concluded that cetirizine was more effective than montelukast for nasal congestion, sneezing, rhinorrhea, and red eyes.

Experts say, both medications are effective for allergic rhinitis treatment but have different active ingredients and mechanisms of action.

However, Zyrtec is more effective but it can cause fatigue and sedation in some patients.

Final words: the best choice for you will depend on your specific symptoms and preferences. Speak with your doctor to find out which drug is right for you.

How To Prevent Allergic Rhinitis

If it is possible to identify the allergen causing the allergic rhinitis, then minimizing exposure to the allergen may reduce the signs and symptoms.

Prevention methods include:

  • use re-circulated air in your car when pollen levels are high;
  • shower after activities where you may have had high exposure to pollen;
  • avoid activities that are known to cause exposure to pollen;
  • stay indoors when possible on windy days, during pollen season, or after thunderstorms.