How Do I Choose the Best Antihistamine for Anxiety?

These drugs can selectively block the histamine H1 receptor and antagonize the effect of histamine to produce antihistamine effect. According to its chemical structure, it can be divided into alkylamines, ethanolamines, ethylenediamines, phenothiazines, piperazines, piperidines and others. This class of drugs is mainly used to treat allergic rhinitis, allergic conjunctivitis and allergic skin diseases.

Antihistamines

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These drugs can selectively block the histamine H1 receptor and antagonize the effect of histamine to produce antihistamine effect. According to its chemical structure, it can be divided into alkylamines, ethanolamines, ethylenediamines, phenothiazines, piperazines, piperidines and others. This class of drugs is mainly used to treat allergic rhinitis, allergic conjunctivitis and allergic skin diseases.

Most drugs in this class have sedative and anti-muscarinic choline effects. Common adverse reactions of antihistamines include central inhibitory effects. Traditional antihistamines can enter the center through the blood-brain barrier and have significant central inhibitory effects. New antihistamines, such as

Drug interactions of this class of drugs include: combined with alcohol and other central nervous system inhibitors (barbiturates, hypnotics, opioid analgesics, anxiolytic sedatives, antiepileptics), which can increase antihistamines The drug has a central nervous system inhibitory effect, but this interaction is weaker for new antihistamines. Combined with anticholinergic drugs (atropine, tricyclic antidepressants, monoamine oxidase inhibitors), it can strengthen the anticholinergic effect of this class of drugs. Some liver metabolized antihistamines and liver drug enzyme inhibitors may cause adverse reactions when they are combined, so it should be noted. Antihistamines can inhibit the skin test response of allergenic substances, so all antihistamine drugs should be stopped for several days before the skin test to avoid affecting the skin test results.

Precautions for the application of antihistamines include drivers of vehicles, aircraft, and precision instrument operators who are prohibited from taking antihistamines with central nervous system suppression before work. Patients with angle-closure glaucoma, urinary retention, benign prostatic hyperplasia, pyloric duodenal obstruction, and epilepsy should be used with caution. Some antihistamines are used. Patients with renal excretion and impaired renal function may need to reduce the dose when taking it; patients with impaired liver function should pay attention when taking phenothiazine antihistamines. Use with caution in pregnant and lactating women. Newborns and preterm infants are more sensitive to the anticholinergic effects of this class of drugs and should not be used. The elderly are more sensitive to adverse reactions to histamines, and are prone to adverse reactions such as hypotension, confusion, dementia and dizziness when applied.

Commonly used H1 receptor antagonist chlortrimeton (chlorpheniramine): Oral: 4mg tid for adults. Children 0.35mg / kg / day, divided into 3 to 4 times. Intramuscular injection: 5-20mg / time. Atarax (hydroxizine): Oral: 25mg, qd ~ qid. Ceramrizine (cinnarizine, mitronal, stutgeron): Oral: 25mg, qd ~ qid. Finnagan (promethazine, phenergan): Oral: 12.5-25mg, qd ~ bid. Injectable, 2ml contains 50mg, intramuscular injection 25mg 50mg, qd. Can also be added to 500ml of physiological saline or 5% glucose solution, qd. Cyproheptadine (periactin): Oral: 2 ~ 4mg, qd ~ qid. Ketotifen: Oral: 1mg, qd ~ bid. Doxepinum: Oral: 25mg-50mg, tid. Astemizole (astemizole): Oral: 10 mg, qd. Terfenadine: Oral: 60mg, bid. Cetirizine (cetirizine, Zyrtec): Oral: 10 mg, qd. Loratadine (loratadine, Clarityne): Oral: 10 mg, qd. Kemin (triprolidini): oral: 2.5 ~ 5mg, bid. Acristin (Sinminle, acrivastine): Oral: 8mg, qd ~ tid.

Commonly used H2 receptor antagonist cimetid: oral: 200-300mg, tid; intravenous drip: 0.4 added 5% glucose solution 500-1000ml, qd. Ranitid: oral: 150 mg, bid.