Loratadine rushed to the hot search! Doctors pay attention to these points!

Every year in April and May, from north to south, plant pollen and fly flotsam in the air make many "allergic stars" have red and swollen eyes, sneezing constantly, and even breathlessness in severe cases.

Recently, the anti-allergy drug #氯雷他定# rushed to the top of the hot search on Weibo, with more than 100 million discussions.

Netizen: "This season, I must bring it in my pocket" "Allergic rhinitis, my life-saving medicine"

This shows that many people are heavily dependent on loratadine.

What should I pay attention to when taking it? Are there any side effects from long-term consumption? We looked up the literature to see what doctors were saying.

▍Loratadine, why has it become a common drug? [2-3]

Loratadine is a second-generation antihistamine that is commonly used to treat allergy symptoms.

Suitable for

Common allergic diseases or symptoms such as acute and chronic urticaria, infantile eczema, allergic rhinitis, allergic conjunctivitis, hay fever, allergic laryngeal edema, allergic cough, contact dermatitis, food allergic reactions, drug allergic reactions, etc. There are also photosensitive dermatitis, cold urticaria, dermatographism, angioedema, atopic dermatitis, insect allergies, etc. The principle of anti-allergies

Loratadine works by blocking histamine H1 receptors, thereby reducing symptoms caused by allergic reactions, such as nasal congestion, runny nose, sneezing, and itchy eyes.

Histamine H1 receptor is a protein found in our body. It is mainly found in places like the nose, skin, respiratory tract, etc.

To put it simply, histamine H1 receptors are like the button that starts an allergic reaction, and allergy drugs turn this button off to make us feel better.

Advantage 1: Does not cause drowsiness

Compared with the first-generation antihistamines chlorpheniramine (chlorpheniramine), cyproheptadine, and diphenhydramine, loratadine does not easily cross the blood-brain barrier of the human body, so side effects such as drowsiness rarely occur

Advantage 2: Long action time

After taking a tablet of 10 mg of loratadine, it is quickly absorbed by the intestines, and after 30 minutes it is detected in the bloodstream and begins to work. The peak time of blood concentration is about 1.5 hours, when the anti-allergic effect is the strongest. Its half-life in the human body is 8~14 hours, and the duration of the effect is 18~24 hours, so you can eat it once a day.

The half-life of a drug is the time it takes for a drug to be metabolized halfway through the body.

A long half-life indicates that the drug metabolism is slow, the number of doses is less, and the interval between doses is longer. The short half-life indicates that the drug is metabolized quickly, the number of doses will increase, and the interval is short.

For example, the half-life of a drug is about 10 hours, and the effect in the plasma after taking the drug can last for 30-50 hours, usually 24 hours apart.

▍What are the adverse effects of loratadine? [1-3]

Adverse effects of loratadine are as follows:

A small number of people may experience symptoms such as headache, fatigue, dry mouth, drowsiness, and emotional instability during the medication. However, these symptoms occur relatively rarely, similar to those of people who take a placebo, so it is uncertain whether they are caused by the drug.

If you overdose, you may experience adverse reactions such as drowsiness, dizziness, and headache, and there is currently no specific antidote. Drugs are usually removed from the body by means of vomiting and gastric lavage, while infusions and general supportive care and symptomatic management are carried out, and vital signs are closely monitored until the patient returns to normal. Histamine should never be used as an antidote to loratadine (which can make the allergic reaction worse).

A very small number of people have allergic reactions such as rash, itching, nausea, vomiting, diarrhea and other allergic reactions during the period of taking the drug, and the drug should be stopped immediately and the drug without allergy should be selected for symptomatic treatment.

▍What should I pay attention to when taking loratadine? [2-4]

Dr. Xu Haibo of the Third Hospital of Hangzhou reminded that the treatment of perennial allergies is mainly topical medication and nasal spray. For example, if the attack is more severe at the turn of the season, it will be recommended to take loratadine for 2-4 weeks. Allergic rhinitis usually improves slowly after 2 weeks, and the medicine is slowly stopped and switched to topical medication (nasal spray) [1].

Pay attention to the following aspects: 1. If you are taking ketoconazole, macrolide antibiotics, cimetidine, theophylline and other drugs, consider that these drugs will increase the concentration of loratadine in the blood, so be cautious about using them at the same time.

2. No adverse reactions such as teratogenicity and carcinogenicity have been found in animal experiments, but women in early pregnancy should still use it with caution; Breastfeeding women should also be careful, as the drug can be passed on to the child through breast milk, especially infants and premature babies are particularly sensitive to it, and the pros and cons should be carefully weighed before taking the drug.

3. If you have severe liver and kidney function problems, be especially careful when using loratadine.

4. At present, loratadine has not been found to cause arrhythmia, QT gap prolongation, weight gain and other problems, but it is still necessary to pay attention to the possible side effects just in case.

5. Loratadine is well controlled for symptoms such as sneezing, runny nose and nasal itching in allergic rhinitis, but the effect on nasal congestion is average, and decongestants can be added when necessary, such as ephedrine, pseudoephedrine, etc.

6. The regular daily dose is 10 mg, there are no special circumstances, the dosage should be strictly controlled within this range, and the dosage should not be increased arbitrarily because of the decrease in effect or drug resistance.

7. For aerial workers, drivers, athletes before the competition and occupations who need to be highly concentrated, the dosage must be controlled within a safe range.

8. Mild to moderate liver and kidney function impairment has no obvious effect on the metabolism and excretion of loratadine, so the dosage of elderly patients is the same as that of adults.

9. Long-term medication, such as continuous medication for more than one month, it is recommended to change the medication appropriately to avoid drug resistance. You can also temporarily stop taking the drug for a period of time and then retake the drug, and the effect should be restored.

10. If you often drink alcohol or take diazepam drugs, you should observe more at the beginning of medication to see if it will aggravate drowsiness or other central inhibitions, adjust the dosage if necessary, or simply do not drink alcohol and take diazepam drugs during the medication.

11. If you have an allergic reaction to loratadine or various additives in it, it should be prohibited, and people with allergies should use it with caution (anti-allergic drugs can also cause allergic reactions).

12. Stop loratadine about 48 hours before you need to do a skin test, as antihistamines can prevent or reduce positive skin test reactions.

13. If loratadine is taken in excess and poisoning occurs, vomiting can be induced. If the patient is awake, gastric lavage can be given saline and activated charcoal. Salt laxatives, such as sodium sulfate, may also be considered to block intestinal absorption of loratadine. Loratadine is not removed by hemodialysis, and it is uncertain whether peritoneal dialysis is effective.

▍Why are they allergic, and sometimes even fatal? [3]

When you have allergies, your body sees something harmless as an enemy, such as pollen, food, or medicine. Your immune system releases a chemical called histamine to fight these "enemies."

Histamine causes blood vessels to dilate and fluid to leak out, resulting in swelling of the body's tissues. If it occurs in the respiratory tract, it can cause edema in the airways and make it difficult for you to breathe.

When you have difficulty breathing and your blood pressure drops sharply, it's called anaphylactic shock. If left untreated, it can be life-threatening. So, if you or someone close to you has this severe allergy, it's best to have emergency medication with you, such as an epinephrine injection pen, so that you can save yourself in time in case of emergency.

bibliography

1. Loratadine rushed to the hot search! Doctor reminds, Guangming Daily 2024-04-20 20:39 Beijing 2.Li Weimei,Wang Lingli,Xuan Weijun. Journal of Guangxi University of Traditional Chinese Medicine,2019,22(01):71-75.3.) JIA Minghui, CHEN Xiaoyun, ZHANG Yue, et al. Efficacy of nasal corticosteroids combined with loratadine or montelukast sodium in the treatment of allergic rhinitis[J].Journal of Clinical Otorhinolaryngology-Head and Neck Surgery,2017,31(05):369-373.DOI:10.13201/j.issn.1001-1781.2017.05.010.4.. LI Meng,ZHANG Xiaohua. Chinese Journal of Modern Drug Application,2013,7(14):159-160.DOI:10.14164/j.cnki.cn11-5581/r.2013.14.224.

Tips: Popular science articles do not provide professional diagnosis and treatment opinions, specific diagnosis and treatment should be carried out under the guidance of professional doctors, the picture comes from the photo network

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