Antihistamines are medications commonly used to treat allergy symptoms. They work by inhibiting the effect of histamine, a chemical substance the body releases in reaction to allergens. This substance causes the well-known bothersome symptoms, making antihistamines the first line of defense for many. Many patients notice a difference in response between one type and another; while some feel rapid improvement with Zyrtec, others prefer Claritin due to less feeling of drowsiness.
What Are Antihistamines and How Do They Work?
To understand the mechanism of action of antihistamines, one must first know the role of histamine itself. When a person is exposed to a substance they are allergic to, the immune system releases histamine, which binds to specific receptors in the body, causing symptoms such as sneezing, itching, and nasal congestion.
Main Types of Antihistamines
Antihistamines are divided into two main groups:
First-Generation Antihistamines
This group includes medications like diphenhydramine and chlorpheniramine. These antihistamines are characterized by their ability to cross the blood-brain barrier, commonly causing drowsiness as a side effect.
Second-Generation Antihistamines
This includes medications like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra). These antihistamines differ from their predecessors in that they typically do not cause drowsiness to the same degree, making them suitable for daytime use. It is noteworthy that Claritin (loratadine), Zyrtec (cetirizine), and Allegra (fexofenadine) are among the most famous brands in this category and are often the first choice for treating seasonal allergy symptoms due to their effectiveness and fewer drowsiness-causing side effects compared to the first generation. However, the response to these antihistamines may vary from person to person.
Top Medications for cold and flu
Medical Uses of Antihistamines
Antihistamines are used to treat a wide range of conditions:
- Seasonal Allergic Rhinitis: Relieves sneezing, itchy nose and eyes, and runny nose
- Hives (Urticaria): Reduces itching and skin swelling
- Skin Allergies: Alleviates symptoms of eczema and contact dermatitis
- Motion Sickness: Some antihistamines help prevent nausea associated with travel
- Insomnia: Some types of antihistamines are used for their sedative properties
Potential Side Effects
Despite the effectiveness of antihistamines, they may cause some side effects:
- Drowsiness and dizziness (especially with first-generation)
- Dry mouth, nose, and throat
- Headache and upset stomach
- Changes in appetite
- Blurred vision in some cases
Which Is Better: Zyrtec or Claritin?
A common question among those suffering from allergies is: Which is better: Zyrtec or Claritin? The truth is that the answer is not the same for everyone, as the choice depends on several individual factors. Both belong to second-generation antihistamines, but there are differences that may make one more suitable than the other for your condition.
Key Differences:
- Onset and Speed of Action: Zyrtec (cetirizine) starts working faster (within approximately one hour), while Claritin (loratadine) may take a bit longer to reach its peak effect.
- Strength of Effect and Duration: Zyrtec is generally considered more effective in relieving severe itching and hives (urticaria), but it may be accompanied by a slightly higher rate of drowsiness compared to Claritin in some users. Claritin is famous for being the least likely to cause drowsiness among common antihistamines.
- Effect on Drowsiness: While both drugs are marketed as "non-drowsy," individual experiences and reports indicate that the likelihood of feeling drowsy or lethargic with Zyrtec is higher than with Claritin, although it is much lower than with first-generation drugs.
- Age Group: Zyrtec is often the preferred choice for younger children in some medical protocols due to a longer history of studies.
Important Tips Before Using Antihistamines
Before taking any antihistamines, the following points should be considered:
Drug Interactions
Antihistamines may interact with other medications such as sedatives, antidepressants, and some blood pressure medications. Always consult your doctor if you are taking other medications.
Special Precautions
Some groups should exercise caution when using antihistamines:
- Elderly: More susceptible to side effects like dizziness and drowsiness
- Pregnant and Breastfeeding Women: Should use antihistamines only under medical supervision
- Children: Appropriate doses for children vary, and not all types of antihistamines are suitable for them
- Individuals with Chronic Diseases: Such as glaucoma, prostate problems, or liver and kidney diseases
Conclusion
Frequently Asked Questions About Antihistamines
Can I take antihistamines daily?
The answer depends on the type of antihistamine and the reason you are using it. Some are safe for daily use over extended periods, while others should be used for limited periods only.
What is the difference between antihistamines and steroids?
Antihistamines differ from steroids in their mechanism of action. While antihistamines only block the effect of histamine, steroids work to reduce inflammation in general and are stronger in treating severe allergy symptoms.
When should I stop using antihistamines?
You should stop using antihistamines and consult a doctor if any serious side effects appear, such as difficulty breathing, swelling of the face or throat, rapid heartbeat, or severe skin rash.
Can the body develop resistance to antihistamines?
Yes, what is called "tachyphylaxis" may occur, where the drug's effectiveness decreases with long-term use. In this case, the doctor may advise changing the type of antihistamine or taking breaks from its use.