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Singulair vs Allegra

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Singulair Overview

Singulair Details

Allegra Overview

Allegra Details

Comparative Analysis

Singulair Prescription Information

Allegra Prescription Information

Singulair Side Effects

Allegra Side Effects


Cost Analysis

Market Analysis



For patients with allergies or asthma, certain drugs that modify the body's response to allergens, referred to as antihistamines and anti-leukotrienes, can help in relieving allergy symptoms and managing allergic reactions. Singulair and Allegra are two such medications often prescribed for these conditions. They each affect different pathways in the immune system but both have effects in alleviating allergy-related discomforts.

Singulair is a leukotriene receptor antagonist which works by blocking substances called leukotrienes that cause inflammation and constriction of airways in the lungs. It is commonly used for long-term prevention of asthma attacks.

Allegra on the other hand, also known as fexofenadine, belongs to a class of drugs called antihistamines. It works by blocking histamine - a substance produced during an allergic reaction - from binding to its receptors thus preventing the triggering of allergic responses like sneezing, itching and runny nose.

Singulair vs Allegra Side By Side

Brand NameSingulairAllegra
ContraindicationsShould not be taken with MAOIsShould not be taken with MAOIs
CostAround $180 for a 30-tablet pack of 10 mg$25-$35 for a box of 70 tablets (180 mg)
Generic NameMontelukastFexofenadine
Most Serious Side EffectThoughts about suicide or self-harm, severe sinus pain, teeth painAllergic reactions including difficulty breathing; swelling of your face, lips, tongue, or throat
Severe Drug InteractionsMAOIsMAOIs
Typical Dose10 mg/day for adults and adolescents over the age of 1560 mg taken twice daily or 180 mg once a day

What is Singulair?

Montelukast (the generic name for Singulair) is a drug belonging to the leukotriene receptor antagonists class, which signifies a substantial evolution from conventional antihistamines. Montelukast was first approved by the FDA in 1998. It works by blocking substances in your body called leukotrienes, effectively preventing them from causing allergy or asthma symptoms such as wheezing, shortness of breath and inflammation of the airways. It is prescribed primarily for long-term treatment of asthma and to relieve symptoms of seasonal allergies.

On the other hand, Fexofenadine (the generic name for Allegra) belongs to a class known as second-generation antihistamines. Unlike Montelukast that targets leukotrienes, Fexofenadine acts by specifically inhibiting histamine H1 receptors thereby reducing allergic reactions like sneezing and itching. While both medications are effective against allergies, their different mechanisms make them better suited for managing different aspects or severity stages of allergic responses.

What conditions is Singulair approved to treat?

Singulair is approved for the treatment of several variations of allergies and asthma:

  • Chronic asthma, including prevention of day and nighttime symptoms
  • Exercise-induced bronchoconstriction (EIB), also known as exercise-induced asthma
  • Seasonal allergic rhinitis, commonly referred to as hay fever
  • Perennial allergic rhinitis, which is year-round nasal allergies.

How does Singulair help with these illnesses?

Singulair works to manage asthmatic symptoms and allergies by blocking the action of leukotrienes in the lungs. Leukotrienes are substances your body releases when you breathe in an allergen (such as pollen), causing swelling, inflammation, and tightening of the muscles around your airways and production of excess mucus, leading to asthma-like symptoms. Therefore, by inhibiting these leukotrienes, Singulair helps prevent wheezing and shortness of breath.

On the other hand, Allegra alleviates allergic reactions by acting on histamine receptors in our bodies. Histamines are natural chemicals that trigger allergy symptoms such as sneezing or itchy eyes. By acting on these receptors and reducing their activity level, Allegra can suppress typical allergy symptoms without inducing drowsiness — a common side effect with some other antihistamines.

What is Allegra?

Allegra, also known by its generic name Fexofenadine, is an antihistamine used to alleviate the symptoms associated with seasonal allergies and chronic urticaria. It operates by inhibiting histamine H1 receptors hence reducing the allergic reactions in the body. Allegra was first approved by FDA in 1996.

Unlike Singulair which is a leukotriene receptor antagonist and works differently from antihistamines like Allegra, it does not cause sedation because it does not pass into the brain from the blood as much as other antihistamines do. This makes Allegra less likely to interfere with mental alertness and physical coordination which are common side effects of some allergy medications.

Furthermore, Fexofenadine has no significant cardiac adverse effect or propensity for weight gain unlike some other drugs used to manage these conditions.

What conditions is Allegra approved to treat?

Allegra, also known by its generic name fexofenadine, is an antihistamine that's approved for use in treating:

  • Seasonal allergies (hay fever)
  • Chronic idiopathic urticaria (hives) without a known cause

Its non-drowsy formula makes it a popular choice for daytime relief of allergy symptoms such as sneezing, runny nose, itchy or watery eyes, and itching of the nose or throat.

How does Allegra help with these illnesses?

Histamine is an organic molecule involved in local immune responses as well as regulating physiological functions in the gut and acting as a neurotransmitter. During allergic reactions, the body produces histamine, which can cause inflammation, runny nose and itchy eyes. Allegra works by inhibiting the action of histamine on H1 receptors, thereby relieving some allergy symptoms such as sneezing, itching and runny nose without causing drowsiness. Unlike Singulair which blocks leukotrienes—chemicals that cause swelling and constriction in your airways—Allegra does not affect this pathway but focuses solely on blocking histamines. This makes it highly effective when dealing with typical hay fever-like allergies while Singulair might be chosen for conditions like asthma where airway constriction is more prevalent.

How effective are both Singulair and Allegra?

Both montelukast (Singulair) and fexofenadine (Allegra) have established histories of success in treating patients with allergies, and they were initially approved by the FDA only a few years apart. Since they act on different receptors, namely leukotriene receptors for Singulair and histamine H1 receptors for Allegra, they may be prescribed under different circumstances.

The effectiveness of montelukast in alleviating allergy symptoms was directly studied in several double-blind clinical trials; this drug exhibited efficacy in managing conditions such as allergic rhinitis and chronic urticaria while maintaining an encouraging safety profile. In these studies, various metrics measuring the relief from nasal congestion, itching eyes or skin rash did not differ significantly between patients receiving montelukast or antihistamines like cetirizine.

A 2004 meta-analysis demonstrated that fexofenadine is effective in alleviating symptoms of hay fever starting from the first dose, it has a favorable side effect profile compared to many other antihistamines due to its non-sedating nature and it's well-tolerated even in elderly populations. These characteristics have made Fexofenadine one of the most widely used antihistamines worldwide.

In 2016 review indicated that Montelukast seems to be more effective than placebo at treating asthma symptoms alongside standard treatment regimens but slightly less effective as monotherapy compared to corticosteroids or long-acting beta agonists. Further research into its use involves Montelukast co-prescribed alongside other anti-allergic medications so data confirming its efficacy as a stand-alone treatment is still being collected. Nonetheless, due to its unique pharmacology targeting leukotrienes which are pro-inflammatory substances involved both allergy-induced inflammation and bronchoconstriction seen during asthmatic attacks makes Montelukast an optimal add-on therapy for those who cannot control their condition with antihistaminic drugs alone.

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At what dose is Singulair typically prescribed?

Oral dosages of Singulair are usually 10 mg/day for adults and adolescents over the age of 15, which is found to be effective in managing symptoms of asthma and seasonal allergies. Children between ages 6-14 may start with a dosage of 5 mg/day. If there's no improvement in symptoms after a few weeks, consult your doctor before adjusting the dose. The maximum daily dose should not exceed 10 mg for adults and adolescents or 5 mg for children aged between six to fourteen years old under any circumstances.

At what dose is Allegra typically prescribed?

Allegra (fexofenadine) treatment is typically initiated at the dosage of 60 mg taken twice daily or 180 mg once a day. If needed, this can be adjusted depending on the severity of your symptoms. For children aged between 2-11 years old, the usual dose is 30 mg twice daily. It's important to note that Allegra should not be taken with fruit juices as they can interfere with absorption of the drug. As with all medications, always follow your doctor's advice when adjusting dosages and if there is no noticeable improvement in symptoms after a few weeks of following the prescribed regimen, it may warrant scheduling an appointment for reevaluation.

What are the most common side effects for Singulair?

Common side effects of Singulair (montelukast) may include:

  • Headache
  • Stomach pain, heartburn or upset stomach
  • Cough, nasal congestion
  • Dizziness, fatigue or drowsiness
  • Dental pain
  • Fever

On the other hand, common side effects of Allegra (fexofenadine) can consist of:

  • Nausea and diarrhea
  • Menstrual cramps
  • Drowsiness or tiredness
  • Headache -Coughing

As always, it's important to communicate with your healthcare provider about any adverse reactions you experience while taking medication. If any symptoms persist or worsen over time, immediate medical attention should be sought.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Singulair?

While both Singulair and Allegra are effective for treating allergies, they can occasionally cause side effects. For Singulair, watch out for the following:

  • Thoughts about suicide or self-harm
  • Signs of allergic reaction: hives, difficult breathing, swelling in your face or throat
  • Tremors or shaking
  • Unusual behavior or mood changes (anxiety, depression)
  • Severe sinus pain
  • Teeth pain

For Allegra:

  • Allergic reactions including difficulty breathing; swelling of your face, lips, tongue, or throat.
  • Irregular heartbeat
  • Flu-like symptoms
  • Rash that spreads and causes blistering and peeling

In both cases if you experience any severe side effects it's important to stop taking the medication immediately and seek medical advice promptly.

What are the most common side effects for Allegra?

The side effects that patients may experience when taking Allegra include:

  • Occasional headaches
  • Nausea or upset stomach
  • Dizziness
  • Sleepiness, though less common as compared to some other antihistamines
  • Dry mouth and throat discomfort
  • Rarely, a rapid heartbeat or palpitations may occur.

While the incidence of these side effects is generally low, everyone's response varies. It's important for patients to consider their lifestyle and personal health factors when choosing between Singulair and Allegra. As with any medication, it's always advisable to discuss potential side effects with your healthcare provider.

Are there any potential serious side effects for Allegra?

While Allegra is generally safe, it's important to stay alert for any potential adverse reactions. The following symptoms may indicate a serious side effect and require immediate medical attention:

  • Signs of an allergic reaction such as hives; difficulty breathing; or swelling of your face, lips, tongue, or throat.
  • Rapid heartbeat or fluttering in your chest
  • Flushing (warmth, redness, or tingly feeling)
  • Nervousness
  • Difficulty concentrating
  • Sleep problems (insomnia)

Less common but more serious side effects could include confusion, mood changes like irritability and agitation. If you observe any unusual physical or mental changes while taking Allegra, seek out medical care immediately.

Contraindications for Singulair and Allegra?

Singulair and Allegra, like most other allergy medications, may cause side effects in some people. If you notice symptoms such as difficulty breathing, swelling of the face or throat (signs of a serious allergic reaction), please seek immediate medical intervention.

Neither Singulair nor Allegra should be taken if you are taking or have been taking certain types of antidepressants known as monoamine oxidase inhibitors (MAOIs). Always inform your physician about any medications you are currently using; MAOIs need around 5 weeks to flush out from your system to avoid hazardous interactions with Singulair and Allegra.

It's also important to note that while both drugs effectively treat allergies, they work differently. Singulair blocks leukotrienes substances in the body that cause inflammation and constriction in the airways and make them produce mucus. On the other hand, Allegra works by blocking histamines substances responsible for allergic symptoms from attaching to cells in your body.

How much do Singulair and Allegra cost?

For the brand name versions of these drugs:

  • The price for a 30-tablet pack of Singulair (10 mg) averages around $180, which works out to about $6/day.
  • A box of 70 Allegra tablets (180 mg) is priced at approximately $25-$35 depending on where you purchase it from. This works out to as little as $0.36 to slightly over $.50 per day.

Therefore, if you are in need of daily allergy relief and require only one tablet a day, then the cost per day is significantly cheaper with brand-name Allegra compared to Singulair.

Please note that cost should not be your primary consideration in determining which medication is right for you.

In terms of generic versions:

  • Montelukast sodium (the active ingredient in Singulair), can be found at prices similar or slightly less expensive than its branded counterpart.
  • Fexofenadine hydrochloride (the active ingredient in Allegra), when purchased as a generic version, can also offer significant savings with costs varying widely but generally falling within the range of $0.15 - $.40 per tablet based on quantity and dosage size.

Popularity of Singulair and Allegra

Montelukast, available as the brand name Singulair, was prescribed to about 3.5 million people in the US in 2020. Montelukast is primarily used for managing asthmatic symptoms and seasonal allergies, accounting for just over 15% of leukotriene receptor antagonist prescriptions in the United States. It has been a popular choice since its introduction due to its ability to both prevent asthma attacks and alleviate allergic reactions.

Fexofenadine, sold under names such as Allegra, was prescribed to approximately 8 million individuals in America during the same period. Fexofenadine is classified as an antihistamine and accounts for around 12% of all antihistamine prescriptions nationwide. Its usage has remained fairly consistent over recent years with minor fluctuations likely linked to shifts in allergenic conditions across different seasons or regions.


Singulair (montelukast) and Allegra (fexofenadine) are both widely used medications for the management of allergy symptoms, with numerous clinical studies backing their efficacy over placebo treatments. Both can be used together in certain cases to manage severe allergies, yet this should always be under careful consideration by a physician due to potential drug interactions. Their mechanisms of action differ significantly; Singulair is a leukotriene receptor antagonist that reduces inflammation and constrictions in the airways, while Allegra works as an antihistamine that blocks histamine's effects.

Both drugs have generic forms available, offering significant cost savings especially when patients must pay out of pocket. With either medication, results might not be immediate -- some patients may require time for these drugs to demonstrate full effectiveness.

The side effect profiles between Singulair and Allegra largely overlap but there are differences: both are generally well-tolerated with mild side effects such as headache or dry mouth being common. However, Singulair has been linked with mood changes including depression and suicidal thoughts in rare cases. Therefore, it's crucial that those on Singulair closely monitor their moods particularly at the start of treatment and seek medical help immediately if depressive symptoms or suicidal tendencies arise.