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Benadryl (Diphenhydramine Hydrochloride) - Summary

 
 



BENADRYL SUMMARY

Benadryl®
(Diphenhydramine Hydrochloride Injection, USP)

Benadryl (diphenhydramine hydrochloride) is an antihistamine drug having the chemical name 2-(Diphenylmethoxy)-N,N-dimethylethylamine hydrochloride.

Benadryl in the injectable form is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when Benadryl in the oral form is impractical.

Antihistaminic

For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled, and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.

Motion sickness

For active treatment of motion sickness.

Antiparkinsonism

For use in parkinsonism, when oral therapy is impossible or contraindicated, as follows: parkinsonism in the elderly who are unable to tolerate more potent agents; mild cases of parkinsonism in other age groups, and in other cases of parkinsonism in combination with centrally acting anticholinergic agents.


See all Benadryl indications & dosage >>

NEWS HIGHLIGHTS

Published Studies Related to Benadryl (Diphenhydramine)

A trial of midazolam vs diphenhydramine in prophylaxis of metoclopramide-induced akathisia. [2012.01]
STUDY OBJECTIVE: The study aimed to evaluate the effects of midazolam and diphenhydramine for the prevention of metoclopramide-induced akathisia... CONCLUSION: Coadministered midazolam reduced the incidence of akathisia induced by metoclopramide compared to placebo but increased the rate of sedation. No difference was detected from diphenhydramine. Routine coadministered 20 mg diphenhydramine did not prevent metoclopramide-induced akathisia. Copyright (c) 2012 Elsevier Inc. All rights reserved.

Effect of short-term diphenhydramine administration on aqueous tear production in normal dogs. [2011.11]
Objective To perform a randomized, placebo-controlled, masked clinical trial using a cross-over design to determine the effect of oral diphenhydramine on aqueous tear production in normal dogs. Animals studied Seventeen dogs with normal ophthalmic examinations...

Evaluation of the subjective and reinforcing effects of diphenhydramine, levetiracetam, and valproic acid. [2011.06]
Few unscheduled sedating medications have been evaluated for their subjective and reinforcing effects in humans. To increase the information available about unscheduled sedating medications and to evaluate the ability of human laboratory measures to discriminate between scheduled and unscheduled sedating drugs, 24 subjects with a history of experience with several classes of drugs of abuse, including sedatives and/or alcohol, and who reported liking a test dose of pentobarbital 300 mg, were randomized to single doses of diphenhydramine 400 mg, levetiracetam 4000 mg, valproic acid 1500 mg, diazepam 30 mg or placebo in a double-blind, 5-way crossover study...

Efficacy of intramuscular nalbuphine versus diphenhydramine for the prevention of epidural morphine-induced pruritus after cesarean delivery. [2011.03]
BACKGROUND: Pruritus is the most common side effect of epidural morphine analgesia. Diphenhydramine is a widely used agent for the treatment of urticarial pruritus. Nalbuphine is a mixed opioid agonist-antagonist and has been reported to be effective in treating opioid-induced pruritus. We compared the effectiveness of intramuscular diphenhydramine and nalbuphine for the prevention of epidural morphine-induced pruritus after cesarean section... CONCLUSION: Nalbuphine proved better than diphenhydramine for prevention of epidural morphine-induced pruritus in patients who underwent cesarean section. Prophylactic intramuscular nalbuphine (10 mg) is effective in decreasing the incidence and severity of pruritus and does not affect analgesia.

Next-day residual sedative effect after nighttime administration of an over-the-counter antihistamine sleep aid, diphenhydramine, measured by positron emission tomography. [2010.12]
Antihistamines often are self-administered at night as over-the-counter (OTC) sleep aids, but their next-day residual sedative effect has never been evaluated using a reliable quantitative method such as positron emission tomography (PET). We performed a double-blind, placebo-controlled, crossover study in which we evaluated the residual effect the next day after nighttime administration of diphenhydramine, a commonly used OTC sleep aid, in terms of brain H receptor occupancy (HRO) measured using (1)(1)C-doxepin-PET...

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Clinical Trials Related to Benadryl (Diphenhydramine)

To Determine if Diphenhydramine Works for Nasal Congestion at Two Different Doses [Completed]
The study was to determine if the drug worked to relieve nasal congestion experienced by people with seasonal allergies.

A Dose Ranging Effect of Preoperative Diphenhydramine on Postoperative Quality of Recovery After Ambulatory Surgery [Recruiting]
Pain after ambulatory surgery remains an unsolved problem in The United States and Europe. It is associated with delayed hospital discharge and it can result to an increased opioid consumption with adverse side effects. The concept of multimodal analgesic technique was introduced more than 15 years ago and several techniques have been studied over the years including non steroidal antiinflammatory drugs (NSAIDs), acetaminophen, gabapentoids, ketamine, local and regional anesthetic techniques. Histamine can have effects on polymodal nociceptors and C-fibers, producing pain which is further increased by neurogenically mediated release of substance P from afferent pain fibers. Several non-selective or H1

- selective histamine receptors antagonists have been demonstrated in animal models and

clinical pain. Chia et al demonstrated that preoperative promethazine had opioid sparing properties without adverse sedative effects in patients undergoing abdominal hysterectomy.

Diphenhydramine is an anti-histamine drug who has been found to be effective in reducing postoperative nausea and vomiting after ambulatory surgery but its effects on postoperative pain and other important outcomes after ambulatory surgery such as time to meet discharge criteria have not being studied.

The MQOR 40 is a validated instrument that was specifically design to evaluate patient recovery after anesthesia and surgery. This instrument can be particularly valid to examine interventions which affect different spheres of patient recovery as is the case of diphenhydramine. The objective of this study is to determine a dose response effect of preoperative diphenhydramine on postoperative quality of recovery after ambulatory surgery. The use of preoperative diphenhydramine can improve patient's quality of recovery, decrease postoperative pain, opioid consumption and opioid related side effects after ambulatory surgery.

The research question: Does a preoperative dose of diphenhydramine improve postoperative quality of recovery after ambulatory surgery? The hypothesis of this study is that preoperative diphenhydramine will improve postoperative pain, Postoperative nausea and vomiting (PONV), sleep which will translate in a better overall quality of recovery.

Pharmacogenetic Factors and Side Effects of Metoclopramide and Diphenhydramine [Recruiting]

Lorazepam, Diphenhydramine Hydrochloride, and Haloperidol Gel in Patients With Nausea [Recruiting]
This randomized clinical trial studies lorazepam, diphenhydramine hydrochloride, and haloperidol gel in patients with nausea. Lorazepam, diphenhydramine hydrochloride, and haloperidol gel, when absorbed into the skin, may be an effective treatment for nausea and vomiting.

Adjunct Sedatives in Procedures Involving Endoscopic Ultrasound (EUS) and Endoscopic Retrograde Cholangiopancreatography (ERCP) [Recruiting]
The purpose of this study is to compare meperidine/midazolam with diphenhydramine, meperidine/midazolam with promethazine, and meperidine/midazolam with placebo as sedation methods. The investigators are interested to see whether adjunct sedatives (diphenhydramine and promethazine) will improve sedation.

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Reports of Suspected Benadryl (Diphenhydramine) Side Effects

OFF Label USE (56)Drug Hypersensitivity (35)Urticaria (31)Hypersensitivity (27)Nausea (27)Drug Ineffective (26)Hallucination (25)Pain (23)Pruritus (22)Product Quality Issue (20)more >>


PATIENT REVIEWS / RATINGS / COMMENTS

Based on a total of 3 ratings/reviews, Benadryl has an overall score of 7.67. The effectiveness score is 7.33 and the side effect score is 6.67. The scores are on ten point scale: 10 - best, 1 - worst.
 

Benadryl review by 43 year old male patient

  Rating
Overall rating:  
Effectiveness:   Considerably Effective
Side effects:   No Side Effects
  
Treatment Info
Condition / reason:   Hives
Dosage & duration:   25 mg taken every 2 hours for the period of 3 days
Other conditions:   None
Other drugs taken:   None
  
Reported Results
Benefits:   At the onset of my condition of hives, I tried to avoid taking any medications and was hoping to ride it out. By the second day, the itching got unbearable so I gave in and took Benadryl to counteract the severe itching I was having. At this stage, the hives were in full swing so the medication was only 50% effective but it helped enough for me to resist scratching myself. As time went by, the itching slowly subsided and the hives went away (lasted about five days).
Side effects:   When I first took Benadryl, I took two tablets (50 mg) on an empty stomach. The medication left me nauseated and lethargic.
Comments:   After the initial dosage taken (described above), I reduced the dosage to just one tablet (25 mg) but I increased the frequency to one tablet every two hours. I figured this would be equivalent to the recommended directions of 2 tablets every 4 hours but I spread the tablets out to keep the effects of the medication fresh. I also learned not to take this medication on an empty stomach. It worked since I did not suffer any nausea, drowsiness, dry mouth, or upset stomach.

 

Benadryl review by medical professional caring for 11 year old male patient

  Rating
Overall rating:  
Effectiveness:   Considerably Effective
Side effects:   Severe Side Effects
  
Treatment Info
Condition / reason:   allergic reaction
Dosage & duration:   50mg taken one time dose for the period of one time dose
Other conditions:   none
Other drugs taken:   solumedrol
  
Reported Results
Benefits:   it was IV push; it was common to parents; it was accessible; dosage for pediatrics was easy to calculate. treated pts itching, swelling and hives.
Side effects:   pt became very agitated. started screaming. couldn't sit still. pt was speaking and not making sense. pt had altered mental status for about 5min. blood pressure and heart rate increased.
Comments:   pt eventualy wore himself out, and fell asleep. itching and swelling relieved.

 

Benadryl review by medical professional caring for 11 year old male patient

  Rating
Overall rating:  
Effectiveness:   Considerably Effective
Side effects:   Severe Side Effects
  
Treatment Info
Condition / reason:   allergic reaction
Dosage & duration:   50mg taken one time dose for the period of one time dose
Other conditions:   none
Other drugs taken:   solumedrol
  
Reported Results
Benefits:   it was IV push; it was common to parents; it was accessible; dosage for pediatrics was easy to calculate. treated pts itching, swelling and hives.
Side effects:   pt became very agitated. started screaming. couldn't sit still. pt was speaking and not making sense. pt had altered mental status for about 5min. blood pressure and heart rate increased.
Comments:   pt eventualy wore himself out, and fell asleep. itching and swelling relieved.

See all Benadryl reviews / ratings >>

Page last updated: 2011-12-09

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