Diphenhydramine Hydrochloride Injection is a sterile, nonpyrogenic solution for intravenous or deep intramuscular use as an antihistaminic agent. Each mL contains diphenhydramine hydrochloride 50 mg and benzethonium chloride 100 mcg in Water for Injection. pH 4.0-6.5; sodium hydroxide and/or hydrochloric acid added, if needed, for pH adjustment.
Diphenhydramine Hydrochloride Injection is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when the oral form is impractical:
For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standardmeasures after the acute symptoms have been controlled and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.
For active treatment of motion sickness.
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.
Published Studies Related to 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...
Clinical Trials Related to 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.
Bioequivalence Between Two Oral Formulations of Diphenhydramine Hydrochloride [Completed]
The purpose of this study is to determine if two formulations of diphenhydramine
hydrochloride are bioequivalent.
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
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
Reports of Suspected Diphenhydramine Side Effects
Completed Suicide (3),
Respiratory Arrest (3),
Cardiac Arrest (3),
Drug Abuse (2),
Electrocardiogram QT Prolonged (1),
Hepatic Failure (1),
Medication Error (1), more >>
Page last updated: 2011-12-09