What does benadryl do
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Understanding the Effects of Benadryl
Benadryl, known scientifically as beta-dimethylaminoethyl benzhydryl ether hydrochloride, is a widely used antihistamine with a variety of applications. This article explores its pharmacological properties, therapeutic uses, and side effects based on multiple research studies.
Antihistamine Properties of Benadryl
Mechanism of Action
Benadryl is primarily recognized for its antihistamine properties. It effectively antagonizes the effects of histamine, a compound involved in allergic reactions. Studies have shown that Benadryl can counteract the spasmogenic effects of histamine on intestinal muscles at very low concentrations, demonstrating a high degree of specificity1. Additionally, it reduces histamine-induced secretion in gastric pouches of dogs by approximately 40%1.
Comparison with Other Antihistamines
When compared to other antihistamines like Pyribenzamine and Neoantergan, Benadryl shows similar effectiveness in antagonizing histamine's depressor action. However, it is unique in its ability to diminish the depressor action of acetylcholine6. This dual action makes it a versatile antihistamine, although Pyribenzamine and Neoantergan may be more potent in preventing fatal histamine shock in guinea pigs6.
Therapeutic Uses of Benadryl
Treatment of Allergic Diseases
Benadryl is extensively used in treating various allergic conditions. It has been found to relieve symptoms in 60% of patients with allergic diseases, including urticaria and pruritis in allergic dermatoses9. However, its effectiveness can be variable and unpredictable, and it is less effective in conditions like allergic rhinitis and asthma complicated by respiratory infections9.
Skin Conditions
Benadryl has shown efficacy in treating skin conditions characterized by cutaneous edema, such as urticaria, acute scleroderma, and atopic dermatitis. It exerts an antispasmodic action on smooth muscle, which helps alleviate these conditions3.
Bronchial Asthma
In the context of bronchial asthma, Benadryl has provided symptomatic relief to a subset of patients who were resistant to other treatments. However, it was not effective in severe asthma attacks or in patients with organic lung or heart changes5. It is more beneficial when used in conjunction with other antiasthmatic drugs5.
Parkinson's Disease
Preliminary studies have indicated that Benadryl may improve symptoms in patients with Parkinson's disease, particularly when used alongside parasympathetic inhibitory drugs like atropine2. This synergistic effect suggests potential benefits in managing this challenging condition.
Behavior Disorders in Children
Benadryl has also been explored for treating behavior disorders in children. A study reported that 61% of children with behavior disorders, especially those with manifest anxiety, showed improvement with Benadryl treatment10. This highlights its potential use in managing acute behavioral disturbances.
Side Effects and Safety
Common Side Effects
The most frequently reported side effect of Benadryl is drowsiness, which can range from mild to severe, including narcolepsy in some cases9. Other side effects include dizziness, dry mouth, and fatigue5. These side effects were observed in a significant proportion of patients, leading to discontinuation in some cases9.
Safety in Children
In studies involving children, no toxic symptoms were observed, indicating that Benadryl is generally safe for pediatric use in managing behavior disorders10.
Conclusion
Benadryl is a versatile antihistamine with a broad range of therapeutic applications, from treating allergic reactions and skin conditions to managing symptoms of Parkinson's disease and behavior disorders in children. While it is effective in many cases, its use can be associated with side effects like drowsiness and dizziness. Understanding these effects can help in optimizing its use for various medical conditions.
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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-RCTPharmacological 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 StudyBiochemical 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 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 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 Study