Antihistamines vs. Corticosteroids: What’s the Difference?
Longhua Liao / Getty Images
Medically reviewed by Corinne Savides Happel, MD
Antihistamines and corticosteroids are both medications used to treat allergies. In this way, they both work on the immune system. Antihistamines are typically used to treat common allergies. They work by reducing the impact of histamine production in the body.
Histamine is a naturally occurring chemical associated with immune system functioning. Corticosteroids are strong anti-inflammatory medications that work to reduce inflammatory processes in the body and reduce overactive immune system activity.
In this article, you’ll learn about antihistamine types, corticosteroid types, the difference between antihistamines and corticosteroids, side effects to consider, and potential drug interactions.
Longhua Liao / Getty Images
What Are Antihistamines?
Antihistamines are a class of drugs that block the effects of histamine in the body. There are two types of antihistamines. The type of antihistamine needed will depend on the reaction or condition being treated.
Types
H1 blockers are a type of antihistamine used to treat allergies. This class of antihistamine also treats:
Common cold symptoms
Short-term insomnia
Anxiety
First-generation antihistamine overdose causes toxicity and can be fatal.
The second type of antihistamine is known as H2 blockers or H2 receptor antagonists.H2-blockers are used to treat gastrointestinal conditions. H2-blockers may be used in the treatment of the following conditions or symptoms:
Chronic acid reflux and heartburn, or gastroesophageal reflux disease (GERD)
Peptic ulcers
Gastritis
Nausea
Vomiting
Motion sickness
Zollinger-Ellison syndrome (tumors grow in the pancreas or duodenum, the upper part of the small intestine)
Related:Heartburn vs. Acid Reflux vs. GERD: Everything You Need to Know
Examples of common H2 blockers include:
What Are Corticosteroids?
Corticosteroids are steroid medications used to treat overactive immune system activity.
Types
Glucocorticoids
Glucocorticoids are a synthetic version of the naturally occurring glucocorticoid hormone present in the body. They help prevent cell tissue and organ damage caused by excessive inflammation by reducing immune system activity.
Glucocorticosteroids are used in the treatment chronic inflammatory health conditions such as:
Rheumatoid arthritis
Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis
Lupus
Vasculitis (blood vessel inflammation)
Asthma
Chronic obstructive pulmonary disease (COPD)
Examples of glucocorticoids include:
Mineralocorticoid
Mineralocorticoids are a class of drugs designed to help regulate water and salt in the body. They work on the adrenal cortex part of the adrenal gland. Mineralocorticoids are used in the treatment of adrenal fatigue and kidney disease.
Related:What Is Adrenal Fatigue?
What’s the Difference Between Antihistamines and Corticosteroids?
Both medications work to reduce immune system activity. The difference between antihistamines and corticosteroids are the chemical processes they are targeting. Antihistamines target histamines to reduce their impact on the immune system and inflammatory processes. Corticosteroids work by reducing upstream chemical reactions causing inflammation.
Side Effects
The following are the side effects of antihistamines and corticosteroids.
Antihistamines Side Effects
Side effects associated with antihistamine use will vary depending on whether you’re taking first- or second-generation antihistamines. Side effects will also vary depending on whether you’re taking H1 or H2 blockers. Side effects of nasal antihistamines include sneezing and upper respiratory infection.
First-generation histamines have the following common side effects:
Drowsiness or excessive fatigue
Dry mouth and eyes
Vision problems
Low blood pressure
Mucus thickening in airways making it more difficult to breathe
Rapid heart rate
Troubles with urinating or passing bowel movements (i.e., constipation)
While side effects can occur, one review of medical literature found most second-generation antihistamines are well-tolerated and serious side effects are rare.
Side effects associated with second-generation antihistamines include:
Headache
Cough and sore throat
Tiredness
Abdominal pain or discomfort
Nausea and vomiting
Side effects of H2 blocker antihistamines tend to be rare but may include:
Fatigue or drowsiness
Joint pains
Headache
Dizziness
Confusion can also occur in elderly patients
Related:Drug and Medication Side Effects
Corticosteroid Side Effects
Short-term side effects of taking corticosteroids include:
Fluid retention causing swelling
Weight gain
Difficulty controlling diabetes
Experts say the anti-inflammatory properties of glucocorticoids are useful for short-term use in most cases, but chronic and systemic use usually causes side effects, and results in reducing sensitivity to the medication.
Long-term or high-dose side effects from corticosteroids can include a series of side effects leading to other health complications, including:
Osteoporosis or severe bone density loss
Insulin resistance
Muscle weakness or atrophy
Severe infection due to reduce immune system activity
Symptoms of Cushing's syndrome
Peptic ulcers
Neuropsychiatric disorders
Related:How Long Do Prednisone Side Effects Last?
Drug Interactions
The following are drug interactions to be aware of when taking antihistamines and corticosteroids. Speak with a healthcare provider before starting any new medication.
Antihistamines
Antihistamines interact with other medications and substances, causing drowsiness or excessive fatigue.
This includes over-the-counter and prescription-strength medications such as:
Sleep medications and other sedatives
Pain medications
Antidepressants
Anti-seizure medications
Antihistamines can also interact with antipsychotics and some drugs to prevent vomiting, such as Compro (prochlorperazine) and Promethazine DM (promethazine and dextromethorphan).
Related:Reducing Your Risk of Adverse Medication Interactions
Corticosteroids
Corticosteroids may interact with medications, impacting the digestive system and metabolism. These include Nizoral (ketoconazole) and Norvir or Kaletra (ritonavir).
If you’re unsure if a medication interacts with antihistamines or corticosteroids, you can ask a pharmacist to review your medication list.
Consuming more than one type of antihistamine at a time without directions from a medical provider is not safe. Antihistamine overdose can cause seizures, hallucinations, and heart attacks, and can be fatal. Moreover, antihistamines and corticosteroids may contain additional medicinal ingredients such as decongestants. Taking more than one type of decongestant increases your risk of overdose. Always check the labels of new and old medications to prevent doubling up on dosage.
Summary
Antihistamines and corticosteroids work to reduce immune system activity. Antihistamines block histamine action that occurs from allergies. Corticosteroids work on additional chemicals involved in the immune system and inflammatory processes. Types of antihistamines include first and second-generation and nasal antihistamines. Types of corticosteroids include synthetic corticosteroids and mineralocorticoids.
Side effects of antihistamines depend on type, with second-generation antihistamines having fewer side effects than first-generation drugs. Corticosteroid side effects include fluid retention and weight gain. Antihistamines interact with other medications causing drowsiness, antipsychotics, and some anti-vomiting medications. Corticosteroids interact with drugs affecting metabolism. If you have questions about a certain medication interacting with an antihistamine or corticosteroid, consult a pharmacist.
Frequently Asked Questions
Are antihistamines and corticosteroids the same?
No. Antihistamines and corticosteroids are not the same. Antihistamines are medications that reduce histamine activity related to allergies. Corticosteroids are medications that reduce immune system activity associated with chronic conditions causing chronic inflammation.
Is it OK to take antihistamines and corticosteroids at the same time?
It’s generally OK to take antihistamines and corticosteroids at the same time, depending on your symptoms and if your healthcare provider advises it. However, taking more than one antihistamine at a time can lead to dangerous health complications unless under the careful direction of a medical provider.
Are antihistamines and corticosteroids safe during pregnancy?
Some antihistamines and/or corticosteroids are recommended to treat certain conditions during pregnancy. It is important to ask your healthcare provider before using any medication during pregnancy.
Are nasal steroids better than antihistamines for nasal allergy?
Yes. Research suggests nasal steroids are better than antihistamines for reducing symptoms of nasal allergy or allergic rhinitis. Nasal steroids performed better in improving sleep, daytime sleepiness, sneezing, itchiness, and congestion. This suggests nasal steroids can be the first option for treating nasal allergy.
Do antihistamines help reduce inflammation?
Yes, antihistamines help reduce inflammation. Antihistamines reduce inflammation by blocking histamine receptors associated with inflammatory immune system responses. Research also suggests they work to reduce inflammation by suppressing different pathways associated with inflammation.
Which medicine is best for allergies?
The medicine that is best for allergies will depend on the cause of the allergic reaction. However, generally speaking, second- generation antihistamines and nasal steroids are best for allergies. Consult with your healthcare provider or pharmacist for additional information specific to your health needs.
