Antihistamines are medications that are used to relieve the symptoms of allergies, such as sneezing, runny nose, and itchy eyes. They work by blocking the effects of histamine, a chemical that is released by the body when it comes into contact with an allergen.
How much antihistamine you can take in 24 hours depends on the type of antihistamine you are taking and your individual needs.
Over-the-Counter Antihistamines
Over-the-counter antihistamines are available in a variety of forms, including tablets, capsules, liquids, and nasal sprays. The recommended dosage for over-the-counter antihistamines varies depending on the product, but most adults and children over 6 years old can take 10-25 mg of an antihistamine every 4-6 hours.
Prescription Antihistamines
Prescription antihistamines are available in a variety of forms, including tablets, capsules, and liquids. The recommended dosage for prescription antihistamines varies depending on the product and your individual needs. Your doctor will work with you to determine the right dosage for you.
How To Take Antihistamines
Antihistamines can be taken with or without food. If you are taking an antihistamine that makes you drowsy, you should take it at night.
Side Effects of Antihistamines
Antihistamines can cause a variety of side effects, including:
- Drowsiness
- Dry mouth
- Blurred vision
- Nausea
- Constipation
- Diarrhea
How To Avoid Side Effects Of Antihistamines
There are a few things you can do to avoid the side effects of antihistamines, including:
- Take the medication as directed by your doctor.
- Avoid taking antihistamines with alcohol or other depressants.
- If you are taking an antihistamine that makes you drowsy, avoid driving or operating heavy machinery.
- If you are experiencing any side effects from antihistamines, talk to your doctor.
When To See A Doctor
You should see a doctor if you experience any of the following symptoms while taking antihistamines:
- Hives
- Swelling of the face, lips, tongue, or throat
- Difficulty breathing
- Dizziness
- Confusion
- Hallucinations
Conclusion
Antihistamines can be an effective way to relieve the symptoms of allergies. However, it is important to take them as directed and to be aware of the potential side effects. If you have any questions or concerns about antihistamines, talk to your doctor.
Table 1: Recommended Dosages of Over-the-Counter Antihistamines
| Medication | Dosage |
|---|---|
| Diphenhydramine (Benadryl) | 25-50 mg every 4-6 hours |
| Chlorpheniramine (Chlor-Trimeton) | 4 mg every 4-6 hours |
| Loratadine (Claritin) | 10 mg once daily |
| Cetirizine (Zyrtec) | 10 mg once daily |
| Fexofenadine (Allegra) | 60 mg once daily |
Table 2: Side Effects of Antihistamines
| Side Effect | Description |
|---|---|
| Drowsiness | Feeling tired or sleepy |
| Dry mouth | Feeling thirsty or having a dry mouth |
| Blurred vision | Difficulty seeing clearly |
| Nausea | Feeling sick to your stomach |
| Constipation | Difficulty having bowel movements |
| Diarrhea | Loose or watery stools |
Table 3: How To Avoid Side Effects Of Antihistamines
| Tip | Description |
|---|---|
| Take the medication as directed by your doctor. | This will help to prevent you from taking too much medication and experiencing side effects. |
| Avoid taking antihistamines with alcohol or other depressants. | This can increase the risk of side effects, such as drowsiness and dizziness. |
| If you are taking an antihistamine that makes you drowsy, avoid driving or operating heavy machinery. | This can help to prevent accidents. |
| If you are experiencing any side effects from antihistamines, talk to your doctor. | Your doctor may be able to lower your dosage or switch you to a different medication. |
Table 4: When To See A Doctor
| Symptom | Description |
|---|---|
| Hives | Red, itchy bumps on the skin |
| Swelling of the face, lips, tongue, or throat | This can be a sign of a serious allergic reaction. |
| Difficulty breathing | This can be a sign of a serious allergic reaction. |
| Dizziness | Feeling lightheaded or faint |
| Confusion | Feeling disoriented or confused |
| Hallucinations | Seeing or hearing things that are not there |
Frequently Asked Questions
Q: How long does it take for antihistamines to work?
A: Antihistamines usually start to work within 30 minutes of taking them. However, it may take up to 2 hours for them to reach their full effect.
Q: How long do antihistamines stay in your system?
A: Antihistamines typically stay in your system for 4-6 hours. However, some antihistamines, such as diphenhydramine, can stay in your system for up to 24 hours.
Q: Can I take antihistamines every day?
A: Yes, you can take antihistamines every day. However, it is important to talk to your doctor if you plan on taking antihistamines for more than 2 weeks.
Q: Are antihistamines safe for children?
A: Yes, antihistamines are safe for children over 6 years old. However, it is important to give children the correct dosage of antihistamine for their age and weight.
Q: Can I take antihistamines with other medications?
A: Yes, you can take antihistamines with other medications. However, it is important to talk to your doctor before taking antihistamines with other medications, as some medications can interact with antihistamines.
Q: What are some tips for avoiding the side effects of antihistamines?
A: Here are some tips for avoiding the side effects of antihistamines:
- Take the medication as directed by your doctor.
- Avoid taking antihistamines with alcohol or other depressants.
- If you are taking an antihistamine that makes you drowsy, avoid driving or operating heavy machinery.
- If you are experiencing any side effects from antihistamines, talk to your doctor.
