Home Allergy Medications Reference Guide to Allergy Medications
Allergy Medications

Reference Guide to Allergy Medications

by BidRx Team
written by BidRx Team
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Highlights  

  • Allergy medications can be used to manage mild to severe allergies. 
  • Many people manage their allergies with over-the-counter medication, but some people require prescription drugs. 
  • Allergy medications are offered as pills, liquids, inhalers, injections, nasal sprays, eyedrops, and topic creams or ointments.
  • The best allergy medication for you will depend on your allergies, symptoms, and severity of symptoms. 
  • Get the best price for your allergy medication with BidRx.

Allergies affect an estimated 20 percent of the world’s population. Most allergies can’t be cured, but they can be managed with the right medication. Finding the right treatment can drastically improve your daily life. 

About Allergy Medications

Allergy symptoms are caused by an exaggerated immune response or reaction to substances. Common allergies include pollen, pet dander, dust, mold, food, and medications. Allergy symptoms and reactions range from mild to severe. 

Most allergies can’t be cured, but they can be managed with treatment. Allergy medications can help to reduce symptoms. The best allergy medication for you will depend on your allergies, symptom type, and symptom severity. 

Allergy medications are available in many forms, including pills, liquids, injections, inhalers, eye drops, nasal sprays, and topical creams or ointments. Some medications are available over the counter (OTC), but some are only available by prescription. Some people may need to take more than one type of medication to manage their allergies. 

Classes of common allergy medications include:

  • Antihistamines
  • Corticosteroids
  • Decongestants
  • Immunotherapy medications
  • Leukotriene inhibitors
  • Mast cell stabilizers
  • Emergency epinephrine 

Antihistamines

Antihistamines work by blocking histamine release from histamine-1 receptors. Keeping histamine-1 receptors from being stimulated helps to prevent symptoms such as skin rash, hay fever, inflammation and narrowing of the airways, or motion sickness. These drugs are typically used to treat allergies, cold symptoms, and flu symptoms. 

Categories — Antihistamines

Antihistamines fall into two categories. The major difference between the categories is the histamine-1 receptors that the drugs act on. 

Antihistamine categories include:

  • First-generation (shorter-acting). First-generation antihistamines are used to treat mild to moderate allergy symptoms. They’re primarily available OTC and last for 12–24 hours. These antihistamines penetrate the brain, so they’re more likely to cause side effects, such as drowsiness.
  • Second-generation (longer-acting). Second-generation antihistamines are typically taken daily to manage allergy symptoms. They most commonly come in oral tablet form, but some are also available as eye drops. These antihistamines are unlikely to penetrate the brain, so they are less likely to cause drowsiness or impair your ability to drive. Second-generation antihistamines are preferred for use in children. 

Over-the-Counter Antihistamines

The majority of antihistamines are available OTC. 

Examples of first-generation OTC antihistamines include:

Examples of second-generation OTC antihistamines include:

Prescription Antihistamines

Most antihistamines are available OTC, but certain medications or strengths require a prescription from a provider.

First-generation antihistamines available by prescription include:

Second-generation antihistamines available by prescription include:

Warnings and Contraindications — Antihistamines

First-generation antihistamines may cause drowsiness and impair your ability to drive or operate machinery. They may also blunt learning in children taking them. 

Talk to your provider before taking antihistamines if you have heart disease, blood pressure problems, thyroid problems, an enlarged prostate, kidney or liver disease, bladder problems, or glaucoma. Also talk to your provider before taking antihistamines if you are pregnant or breastfeeding.

Side Effects — Antihistamines

Talk to your provider about potential side effects before taking antihistamines. First-generation antihistamines are more likely to cause side effects than second-generation antihistamines. However, taking second-generation antihistamines in high doses or with other medications can increase your risk of side effects.

Potential side effects include:

  • Abdominal pain
  • Blurred vision
  • Confusion
  • Dry mouth
  • Drowsiness or sedation
  • Dizziness
  • Headache
  • Low blood pressure
  • Mucus thickening in airways
  • Nausea or vomiting
  • Rapid heart beat
  • Restlessness 
  • Urinary problems

Drug Interactions —  Antihistamines

Talk to your doctor about potential drug interactions prior to using antihistamines. First-generation antihistamines are more likely than second-generation antihistamines to interact with other medications. 

Antihistamines may interact with certain tricyclic antidepressants, antipsychotics, and drugs used to prevent vomiting. They may also interact with other drugs that cause drowsiness, such as sedatives, muscle relaxers, seizure medications, or sleep medications.

Corticosteroids

Nasal spray

Corticosteroids are a type of steroid that treat swelling and inflammation from allergies and allergic asthma. They work by reducing the production of chemicals that cause inflammation. They can be taken either short-term or long-term to treat a variety of allergies. 

Common Forms of Corticosteroids

Corticosteroids are available as nasal sprays, topical creams and ointments, inhalers, oral tablets, eye drops, and injections. However, nasal corticosteroids are the most common type of corticosteroid used to treat allergies. Other forms of corticosteroids are most often used for specific allergies or related conditions.

  • Nasal corticosteroids. Nasal corticosteroid sprays are available both OTC and by prescription. They are considered safe and effective for use in most adults and children. Nasal sprays can be taken with oral antihistamines and other allergy medications, as needed and as directed by a provider. 
  • Oral corticosteroids. Oral corticosteroids also work to reduce inflammation. However, these drugs work throughout the body, rather than in one targeted area. They are most commonly prescribed for severe pollen allergies and skin allergies. Oral corticosteroids come in tablet or liquid form. These drugs are powerful and typically only used for short periods of time.
  • Other corticosteroids. Other corticosteroids, such as topical creams, eye drops, inhalers, and injections, are not as commonly used for allergies.These may be prescribed or recommended by a doctor for severe allergies or specific conditions, such as allergic asthma. 

Your provider can help you to choose the best option and treatment plan for your allergy symptoms. Talk to your provider if you have severe allergies and believe you are in need of a corticosteroid inhaler, topical cream, or injections.

Over-the-Counter Corticosteroids

There are several nasal corticosteroid sprays available OTC. 

Common examples include:

Prescription Corticosteroids 

There are many different prescription corticosteroids on the market. The most common prescription corticosteroids used to treat allergies are nasal corticosteroids. Oral corticosteroids are sometimes prescribed to treat allergic reactions or severe allergies.

Prescription nasal corticosteroids include:

The most common oral corticosteroids for allergic reactions include:

Warnings and Contraindications — Corticosteroids

People with certain health conditions may experience additional risks or side effects when taking corticosteroids. Nasal corticosteroids can sometimes make asthma symptoms worse. Corticosteroids may not be safe for people who are pregnant or breastfeeding. 

Talk to your doctor before using corticosteroids if you have a history of:

  • Nasal injury or surgery
  • Nasal sores
  • Liver disease
  • Type 2 diabetes
  • Thyroid problems
  • Glaucoma
  • Heart attack
  • Chronic infections

Side Effects — Corticosteroids

Talk to your provider about potential side effects before taking corticosteroids. Nasal corticosteroids typically have fewer side effects than oral corticosteroids. Oral corticosteroids share similar side effects, but they’re more likely to cause more severe side effects.

The most common side effect of nasal corticosteroids is irritation of the nose and throat. Other side effects are rare but may include:

  • Dizziness
  • Eye pain or irritation
  • Headaches
  • Nose bleed
  • Nose sores
  • Trouble breathing
  • Swelling in the face
  • Vision changes

Potential side effects of oral corticosteroids include:

  • Anxiety
  • Changes in appetite
  • Depression
  • Hallucinations
  • Increased blood pressure
  • Joint pain
  • Suppressed immunity 
  • Water retention

Drug Interactions —  Corticosteroids

Nasal corticosteroids are less likely to interact with other medications than oral corticosteroids, but certain drugs may interact or affect your metabolism of corticosteroids, such as ketoconazole (Nizoral) and ritonavir (Norvir).

Decongestants

Decongestants help rid the body of mucus and reduce mucus formation within the nasal passages or eyes. Most decongestants reduce swelling and mucus by activating alpha-adrenergic receptors. This causes the blood vessels to narrow, which reduces blood flow, shrinks swollen tissue, and ultimately relieves congestion. 

Decongestants are commonly used alongside antihistamines or with other allergy medications. They do not prevent allergy symptoms, but they can help to provide symptom relief. You can find decongestants in tablet, capsule, liquid, eye drop, or nasal spray form. 

Over-the-Counter Decongestants

Most decongestants can be purchased OTC. Certain decongestant formulas, such as those containing pseudoephedrine, can only be purchased by people 18 years or older. Some states require a prescription for certain decongestant formulas. 

Common OTC decongestants include:

Warnings and Contraindications — Decongestants

People with certain health conditions may experience additional risks or side effects when taking decongestants. 

Talk to your provider before taking decongestants if you have:

  • Diabetes
  • High blood pressure
  • Thyroid problems
  • Liver, kidney, or heart problems
  • Urinary problems
  • Glaucoma
  • An enlarged prostate

Nasal decongestants should not be used for more than several days in a row. Overuse of nasal decongestants can cause a rebound effect, which can make congestion worse. Oral decongestants are not likely to cause rebound but should not be taken more than a few days in a row without provider approval. 

Side Effects — Decongestants

Talk to your provider about potential side effects before taking decongestants. The most common side effects of oral decongestants are insomnia and irritability. 

Other potential side effects include:

  • Dizziness
  • Excitability 
  • Headache
  • Nervousness
  • Tremors

Drug Interactions —  Decongestants

Talk to your doctor about potential drug interactions prior to using OTC decongestants. They may interact with antidepressants, other cold and allergy medications, drugs used to treat migraines, or hypertension medications.

Immunotherapy for Allergies

Immunotherapy for allergies involves gradually exposing a person to allergies, such as pollens or molds. Under careful and intentional care, this treatment can help train the body’s immune system to stop reacting to specific allergens. 

Immunotherapy may be used for allergies if traditional medications and therapies are ineffective. Drugs used in this way are categorized as allergenics, and the process takes approximately three to five years. The medication is administered via one of the following:

  • Oral (sublingual) allergy tablets. Oral tablets containing allergen extracts are administered under the tongue. These tablets dissolve in the mouth and are typically taken once per day. 
  • Allergy injections. Allergy injections are tailored to the patient. They are administered regularly over the course of several years. 

Prescription Allergenics 

Allergenics are only available by prescription. Your provider will determine the best course of treatment for your allergies. If you require allergy injections, then your provider will secure the correct medication for your specific allergens, following further testing.

Oral allergy tablets include:

Warnings and Contraindications — Immunotherapy for Allergies

Immunotherapy does not work for everyone. People with severe allergies, food allergies, or severe asthma aren’t good candidates for immunotherapy. 

Risks and warnings vary by the specific therapy used. Talk to your provider about your risks and other health conditions prior to beginning immunotherapy. 

Side Effects — Immunotherapy for Allergies

Side effects vary by the therapy being used. The most serious potential side effect for all immunotherapy drugs is severe allergic reaction or anaphalyxsis. 

Drug Interactions —  Immunotherapy for Allergies

Drug interactions vary by the therapy being used. Do not begin immunotherapy without first talking to your provider about all prescription, OTC, and herbal therapies and products you currently use.

Leukotriene Modifiers

Leukotrienes are substances that cause airway constriction, increased mucus production, and swelling and inflammation in the lungs. Leukotriene modifiers prevent leukotrienes from acting in the body. By stopping this action, these drugs prevent wheezing, coughing, shortness of breath, and postnasal drip.

Leukotriene inhibitors are also commonly referred to as antileukotrienes, leukotriene receptor antagonists, and leukotriene synthesis inhibitors. They fall into two different categories:

  • Leukotriene-receptor antagonists. These drugs prevent leukotrienes from binding to their receptors. 
  • Leukotriene synthesis inhibitors. These drugs block the enzyme 5-lipoxygenase, which prevents leukotrienes from forming. 

Prescription Leukotriene Modifiers

Leukotriene modifiers are only available by prescription. Though there are several leukotriene modifiers on the market, only one is approved to treat allergies. The others are primarily used to treat asthma. 

The only leukotriene modifier currently approved to treat asthma and allergies is montelukast (Singulair).

Warnings and Contraindications — Leukotriene Modifiers

People with certain health conditions may experience additional risks or side effects when taking leukotriene modifiers. 

These drugs may not be safe for people with a history of:

  • Mental illness or psychosis
  • Phenylketonuria (PKU)
  • Severe allergic reactions to aspirin or an NSAID

Stop taking montelukast and tell your doctor right away if you experience changes in mood or behavior, allergic reaction, skin rash, numbness in your limbs, severe sinus pain, or flu-like symptoms. 

You should not give montelukast to a child without provider approval. Talk to your doctor if you become pregnant or begin breastfeeding while taking montelukast. 

Side Effects — Leukotriene Modifiers

Talk to your provider if you have a history of mental illness or psychosis prior to taking leukotriene inhibitors. These drugs can cause psychological symptoms, such as anxiety, depression, insomnia, and suicidal thinking or behavior.

Drug Interactions — Leukotriene Modifiers

Talk to your doctor about potential drug interactions prior to using leukotriene modifiers. These drugs may interact with drugs that stimulate liver metabolism, such as phenytoin (Dilantin) or certain antibiotics, such as rifampin. 

Mast Cell Stabilizers

Mast cell stabilizers can help prevent allergic reactions if taken regularly. They work by blocking the release of chemicals that contribute to allergic reactions. They are safe for most people to use but must be used consistently for the best results. 

Mast cell stabilizers are typically used when antihistamines are ineffective at relieving symptoms or when a patient can’t take them. They are commonly found in liquid, inhaler, and eye drop form. 

Prescription Mast Cell Stabilizers

Mast cell stabilizers are only available by prescription. 

Examples of commonly prescribed mast cell stabilizers include:

Warnings and Contraindications — Mast Cell Stabilizers

People with certain health conditions may experience additional risks or side effects when taking mast cell stabilizers. These drugs may not be safe for people who are pregnant or breastfeeding. 

Talk to your provider before using mast cell stabilizers if you have kidney disease or liver disease. These drugs are not approved for use in children under two years of age.

Side Effects — Mast Cell Stabilizers

Talk to your provider about potential side effects before taking mast cell stabilizers. These drugs can cause serious side effects or allergic reactions.

Stop taking your medication and talk to your provider immediately if you have:

  • Signs of allergic reaction, including hives, difficulty breathing, swelling in your face, lips, tongue, or throat
  • Tight feeling in your chest
  • White patches or sores inside your mouth or on your lips

Potential side effects of mast cell stabilizers include:

  • Diarrhea
  • Headache
  • Irritability
  • Muscle pain
  • Nausea
  • Rash or itching
  • Stomach pain

Drug Interactions —  Mast Cell Stabilizers

Talk to your doctor about potential drug interactions prior to using mast cell stabilizers. These drugs may interact with prescription, OTC, vitamin, or herbal therapies and products. 

Emergency Epinephrine (Injection)

Emergency epinephrine is a life-saving drug used during severe allergic reactions. Epinephrine works by relaxing muscles in the airways and tightening blood vessels to reverse the symptoms of anaphylaxis. It’s commonly used for severe food or nut allergies, bee stings, and other severe allergies in people with a history of anaphylaxis.

Emergency epinephrine injections come as an auto-injector and can be administered by the person experiencing anaphylaxis or a bystander. 

Prescription Epinephrine

Injectable epinephrine is only available by prescription. Examples of epinephrine include Adrenaclick, Auvi-Q, EpiPen, and others. 

Warnings and Contraindications — Emergency Epinephrine

Some allergic reactions may require a second injection. You should always call 911 or seek immediate medical attention when administering epinephrine. Your provider will train you on the proper way to use your auto-injector, depending on the brand you use. 

Don’t use epinephrine without provider approval. Tell your provider if an epinephrine injection has ever caused an allergic reaction or caused a reaction to get worse, or if you are pregnant or breastfeeding.

Talk to your provider before using epinephrine if you have a history of:

  • Asthma
  • Depression or mental illness
  • Diabetes
  • Heart disease
  • High blood pressure
  • Thyroid problems

Side Effects — Emergency Epinephrine

Older adults are more likely to experience side effects from epinephrine. Talk to your provider immediately if you notice pain, swelling, redness, or warmth around your injection site.

Potential side effects include:

  • Dizziness
  • Fast, irregular, or pounding heartbeat
  • Feeling restless, fearful, anxious, nervous, or excited
  • Headache
  • Nausea and vomiting
  • Pale skin
  • Sweating
  • Trouble breathing
  • Weakness or tremors

Drug Interactions —  Emergency Epinephrine

Talk to your doctor about potential drug interactions prior to using emergency epinephrine. It may interact with prescription, OTC, vitamin, or herbal therapies and products.

Epinephrine may interact with:

  • Asthma medication
  • Antidepressants
  • Ergot medicine (dihydroergotamine, ergotamine, ergonovine, methylergonovine)
  • Cold or allergy medication
  • Heart or blood pressure medication
  • Thyroid medication

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The BidRx team is a group of professional medical and healthcare writers

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