Antihistamines vs. Corticosteroids: What’s the Difference?

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, and side effects to consider.
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.1
Types
H1 blockers are a type of antihistamine used to treat allergies. This class of antihistamine also treats:2
• Common cold symptoms
• Short-term insomnia
• Anxiety
Warning
First-generation antihistamine overdose causes toxicity and can be fatal.3
The second type of antihistamine is known as H2 blockers or H2 receptor antagonists.3H2-blockers are used to treat gastrointestinal conditions. H2-blockers may be used in the treatment of the following conditions or symptoms:4
• Chronic acid reflux and heartburn, or gastroesophageal reflux disease (GERD)
• Peptic ulcers
• Gastritis
• Nausea
• Vomiting
• Motion sickness
• Zollinger-Ellison syndrome
Examples of common H2 blockers include:
• Axid (Nizatidine)
• Pepcid (Famotidine)
• Zantac (Ranitidine)
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.5
Glucocorticosteroid Uses
Glucocorticosteroids are used in the treatment chronic inflammatory health conditions such as:5
• 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:
• Prednisone
• Prelone (Prednisolone)
• Medrol (Methylprednisolone)
• Kenalog (Triamcinolone)
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.5
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.3
First-generation histamines have the following common side effects:3
• 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.3
Side effects associated with second-generation antihistamines include:3
• 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:3
• Fatigue or drowsiness
• Tenderness or muscle pain, including breast swelling
• Joint pains
• Headache
• Dizziness
• Confusion can also occur in elderly patients
Corticosteroid Side Effects
Short-term side effects of taking corticosteroids include:7
• Fluid retention causing swelling
• Weight gain
• High blood sugar (hyperglycemia)
• Difficulty controlling diabetes