Benadryl does what
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The Multifaceted Effects of Benadryl: An Overview
Antihistamine Properties of Benadryl
Benadryl, chemically known as β-dimethylaminoethyl benzhydryl ether hydrochloride, is primarily recognized for its potent antihistamine properties. It effectively counteracts the spasmogenic effects of histamine on intestinal muscles at very low concentrations, demonstrating a high degree of specificity against histamine1. This specificity is comparable to the action of atropine against acetylcholine, making Benadryl a highly effective antihistamine agent1. Additionally, Benadryl has been shown to reduce histamine-induced gastric secretions in dogs by approximately 40%1.
Benadryl in Allergic Reactions and Skin Conditions
Benadryl is widely used in the treatment of various allergic conditions. It has been found to be particularly effective in relieving symptoms of urticaria, acute scleroderma, and atopic dermatitis3. In a study involving 223 patients with allergic symptoms, Benadryl provided relief to 60% of the participants10. However, its effects are palliative, and symptoms often recur upon withdrawal of the drug10. Despite its efficacy, side effects such as drowsiness are common, occurring in 63% of patients10.
Benadryl in Respiratory Conditions
Benadryl has also been evaluated for its effectiveness in treating bronchial asthma. In a study involving 30 adult asthmatics, 23% experienced symptomatic relief with Benadryl, particularly those without acute upper respiratory infections or organic lung lesions5. However, it was not effective in severe asthma attacks and was most beneficial when used alongside other antiasthmatic drugs5. Additionally, Benadryl and its derivatives have shown significant bronchodilator activity, preventing histamine-induced bronchoconstriction in isolated lung studies7.
Benadryl in Parkinson's Disease
Interestingly, Benadryl has been explored as a treatment option for Parkinson's disease. Preliminary reports indicated that patients with arteriosclerotic Parkinsonism experienced considerable improvement in symptoms when treated with Benadryl, especially when used in combination with parasympathetic inhibitory drugs2. This suggests a potential synergistic effect that warrants further investigation.
Benadryl in Behavioral Disorders
Benadryl has also been administered to children with behavioral disorders, showing improvement in 61% of the cases8. It was particularly effective in children with primary behavior disorders and manifest anxiety, highlighting its potential use in managing acute behavioral disturbances8.
Pharmacokinetics and Side Effects
Benadryl is rapidly absorbed, with clinical effects observed within an hour of administration6. It is distributed in various tissues and excreted in small amounts in the urine6. Common side effects include drowsiness, dizziness, dry mouth, and fatigue, which were reported by a significant number of patients in various studies5 10.
Conclusion
Benadryl is a versatile drug with a wide range of applications, from treating allergic reactions and skin conditions to managing respiratory issues and even behavioral disorders. Its primary action as an antihistamine makes it effective in counteracting histamine-induced symptoms, although its use is often accompanied by side effects such as drowsiness. Further research is needed to fully understand its potential in treating conditions like Parkinson's disease and its long-term effects on behavior disorders.
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Most relevant research papers on this topic
The anti-histamine properties of benadryl, beta-di-methylaminoethyl benzhydryl ether hydrochloride.
Benadryl effectively antagonizes histamine's spasmogenic effects on intestinal muscle, with a degree of specificity approaching that of atropine against acetylcholine.
Non-RCT
Animal StudyBenadryl in the Treatment of Parkinson's Disease
Benadryl shows considerable improvement in symptoms of Parkinson's disease when combined with parasympathetic inhibitory drugs, suggesting potential synergistic effects.
Case ReportBenadryl in the treatment of certain diseases of the skin.
Benadryl's effectiveness in treating cutaneous edema, scleroderma, and atopic dermatitis suggests its potential as a new treatment for these conditions.
The nature of benadryl activity: glucose tolerance curves.
Benadryl has a mildly negative effect on glucose tolerance, causing a decrease in blood sugar levels in subjects after a single dose.
Non-RCTEvaluation of dimethylaminoethyl benzhydryl ether hydrochloride (benadryl) in bronchial asthma.
Abstract 1.1. Benadryl was administered orally in dosages of 150 to 400 mg. daily to a group of thirty adult asthmatics who were resistant to all forms of the usual asthmatic remedies. 2.2. Seven or 23 per cent of the patients experienced symptomatic relief. Withdrawal of the drug was followed by recurrence of symptoms. 3.3. Benadryl was beneficial to those patients whose asthmatic symptoms were not due to acute upper respiratory infections or to demonstrable organic lesions in the lungs or heart. 4.4. Twenty-three or 77 per cent of the patients failed to obtain any relief whatsoever. All of them showed organic changes in the lungs or heart or an active sinus infection. 5.5. The drug was without immediate effect upon severe attacks of asthma, regardless of etiology. 6.6. Benadryl was found to be helpful when used in conjunction with known antiasthmatic drugs. 7.7. Side reactions such as drowsiness, dizziness, dry mouth and fatigue occurred in twenty-eight or 93 per cent of the patients.
Non-RCTBiochemical studies on diphenhydramine (benadryl) distribution in tissues and urinary excretion.
Benadryl rapidly enters the body and rapidly affects symptoms, with a small amount remaining unaltered in urine.
A comparison of the bronchodilator activity of benadryl with some of its derivatives and certain other substances.
Benadryl and its derivatives are the most effective in preventing histamine constriction in lungs, with Benadryl being more consistent and reliable than other agents.
In Vitro StudyThe treatment of behavior disorders in childrenwith benadryl: A preliminary report
Benadryl shows some improvement in 61% of children with behavior disorders, particularly in primary disorders, and is safe for use in acutely disturbing situations without toxic symptoms.
Observational StudyPharmacological properties of antihistamine drugs, benadryl, pyribenzamine and neoantergan.
Benadryl, pyribenzamine, and Neoantergan all effectively reduce histamine's depressor effect in dogs, but Benadryl has a more specific antihistamine action and is more potent in preventing fatal histamine shock in guinea pigs.
Non-RCTAnimal Studybeta-dimethylaminoethyl benzhydryl ether hydrochloride (benadryl); its use in allergic diseases.
Benadryl is a useful drug for treating allergic symptoms, but its effectiveness varies and side effects are common, making it useful for those able to tolerate it for symptom control during allergic investigations.
Observational Study