Some statistics show that most patients who come to dermatology have allergic diseases including urticaria, eczema, seasonal dermatitis, atopic dermatitis, and papular urticaria. At this point doctors tend to prescribe anti-allergy drugs to treat them. Even pruritus, in order to achieve the effect of anti-itch will also apply anti-allergy drugs. In the face of a wide range of clinical anti-allergy drugs, how to improve the effectiveness of drugs, reduce the adverse effects of drugs, the rational choice of drugs which is very delicate.
First, the classification of anti-allergy drugs.
1, antihistamines.
Antihistamines are the most commonly used anti-allergy drugs for type I allergic reactions, which have developed into the third generation. The first generation of antihistamines are paracetamol, cyproheptadine, diphenhydramine, promethazine and so on. Its sedation and central nervous system adverse reactions are more obvious, after taking will appear drowsiness, weakness, slow reaction and other symptoms, after using the drug should avoid driving, precision instrument operation, high-altitude work, etc.. These drugs also have anticholinergic effects, and should be used with caution in patients with prostate hypertrophy, glaucoma, low liver and kidney function, and elderly patients. Second-generation antihistamines include loratadine, cetirizine, imipramine, astemizole, terfenadine, etc. The central nervous system adverse effects of these drugs are greatly reduced. However, it is worth noting that asmipramine and terfenadine have rare serious cardiotoxicity, which can cause fatal arrhythmia, especially when combined with ketoconazole, itraconazole and erythromycin, the above-mentioned adverse effects will be aggravated and should be taken seriously. The third generation antihistamines are desloratadine, levocetirizine, etc., which have lighter side effects and stronger anti-allergic effects.
2. Allergic reaction inflammatory mediator inhibitors.
Allergic response mediator blockers, also known as mast cell stabilizers, mainly ketotifen, sodium cromoglycate, sodium cromolyn, etc., are commonly used in the treatment of allergic rhinitis, bronchial asthma, allergic dermatitis and other diseases. These drugs have little toxicity, safer, but slow onset of action, generally after 1-2 weeks of continuous medication, so you need to be patient, regular medication, not arbitrary interruption.
3, calcium.
Calcium can increase the denseness of capillaries and reduce their permeability, thus reducing exudation to relieve allergy symptoms. Generally used in the treatment of itchy skin, eczema, urticaria and other allergic diseases. Commonly used drugs include calcium lactate, calcium gluconate, etc.
4.Immunosuppressants.
Immunosuppressants such as methotrexate can inhibit the effect of abnormal immunity of the body. At present, they are widely used in persistent exogenous allergic diseases, organ transplant rejection and autoimmune diseases.
5.Chinese medicine.
Chinese herbal medicine compound such as anti-feng and antipruritic, single herbal medicine such as thornbush, bupleurum and perilla and its extracts can play a role in various aspects of allergic reactions, such as inhibiting the formation of IgE, protecting and stabilizing mast cell membranes, reducing and preventing their degranulation, inhibiting the release of allergic mediators such as SAS-A and histamine, increasing the level of intracellular cAMP, eliminating hypersensitive mediators, neutralizing allergens, etc., and causing abnormal intra- and extracellular substance exchange and metabolism. In turn, it inhibits the release of SAS-A, histamine and other allergic mediators, increases the level of intracellular cAMP, eliminates hypersensitive mediators, neutralizes allergens, and alleviates the abnormal exchange of internal and external substances and metabolism, thus inhibiting the damage to target organs and cells caused by antigenic and antibody reactions and allergic mediators, and improving or eliminating clinical symptoms. At the same time, some traditional Chinese medicines, in addition to regulating cellular immunity and humoral immunity, can also enhance the non-specific immune function of the body to varying degrees, bringing into play the body’s own dynamics and helping to eradicate certain persistent allergic diseases.
6, vitamin C.
Vitamin C with antioxidant effect is through the protection of cells, thus reducing or avoiding the occurrence of allergic reactions. Acute and severe allergic skin disease or glucocorticoids should be used because of their fast onset and strong effect.
Second, the principles of the selection of anti-allergy drugs.
1. Select symptomatic medication.
① cold urticaria preferred to cetirizine.
② Choose fast-acting anti-allergic drugs for acute allergic reactions, and choose safe anti-allergic drugs for chronic allergic reactions.
③ It is advisable to use anti-allergy drugs without sedative effect during the day, and anti-allergy drugs with sedative effect at night before going to bed.
2.When combined medication is needed for the condition, it is not advisable to stop all medications immediately after the symptoms are controlled, but should be gradually stopped one by one. This is very important, many patients with chronic urticaria, chronic eczema, the reason for the recurrence of the disease is because the symptoms are slightly better immediately stop the drug caused.
3, continuous use of the same anti-allergy drugs should not exceed one month, otherwise the long-term use of drugs will lead to a decline in efficacy, drug resistance, while drug toxic side effects will continue to accumulate.
4, after taking anti-allergy drugs, symptoms do not improve or symptoms aggravated, should not increase the dose of drugs. As anti-allergic drugs may have certain allergenicity, such as Benadryl can cause drug rash, so when taking an anti-allergic drug is not effective, you should switch to other anti-allergic drugs with different mechanisms of action.