Diphenhydramine
Description
Diphenhydramine is an antihistamine with a mild sedative action which is used to prevent or treat allergic reactions like hay fever or urticaria caused by pollen, dust, or animal hair. It is also used to treat common cold symptoms and as a non-prescription sleep inducing agent.
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Side effects
Major & minor side effects for Diphenhydramine
- Hypersensitivity
- Dry mouth
- Sleepiness or unusual drowsiness
- Fatigue
- Headache
- Nausea or Vomiting
Uses of Diphenhydramine
What is it prescribed for?
- Allergic conditions
- Motion sickness
- Insomnia
- Parkinson's disease
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Concerns
Commonly asked questions
- Onset of actionThe effect of this medicine can be observed within 15-30 minutes of administration of the dose.
- Duration of effectDiphenhydramine remains active in the body for an average duration of 4-6 hours after administration of the dose.
- Safe with alcohol?Use of alcohol along with Diphenhydramine is not recommended since the combination increases the risk of side-effects like dizziness and drowsiness. It is advised that you do not perform any activities that require high mental alertness like driving a vehicle or operating machinery if you consume alcohol with this medicine.
- Is it habit forming?No habit forming tendencies were reported.
- Usage in pregnancy?Diphenhydramine is not recommended for use in pregnant women unless strictly indicated. The benefits and risks should be discussed with the doctor before using this medicine.
- Usage while breast-feeding?This medicine is not recommended for use in breastfeeding women. Alternative treatment options should be considered under your doctor's supervision.
Allergy
This medicine is not recommended for use in patients with a known allergy to Diphenhydramine or any other components present in this medication.
Neonates and premature infants
This medicine is not recommended for use in newborn children and premature infants due to the risk of serious side effects.
Benign prostatic hyperplasia
Diphenhydramine is not recommended for use in patients with benign prostatic hyperplasia (enlarged prostate) since taking the medicine may cause increased difficulty in passing urine.
Asthma
Use of Diphenhydramine in patients with asthma/COPD is not recommended since it may increase the risk of further lung problems like respiratory tract blockage. This risk is especially higher in elderly patients. It is advised to use alternative agents with lesser side effects.
Glaucoma
Use of Diphenhydramine in patients with glaucoma is not recommended since it may increase the intraocular pressure, leading to an increased risk of vision problems like dry eyes and blurred vision. This risk is especially higher in elderly patients and patients wearing contact lenses.
Gastrointestinal blockage
Use of Diphenhydramine in patients with gastrointestinal obstruction is not recommended since this medicine may worsen the condition. The risk is especially higher in elderly patients.
Cardiovascular Disease
Use of Diphenhydramine in patients with cardiovascular disease is not recommended since it may lead to increased heart rates, low blood pressure, and changes in ECG. The risk is especially higher in elderly patients.
Warnings for special population
Pregnancy
Diphenhydramine is not recommended for use in pregnant women unless strictly indicated. The benefits and risks should be discussed with the doctor before using this medicine.
Breast-feeding
This medicine is not recommended for use in breastfeeding women. Alternative treatment options should be considered under your doctor's supervision.
General warnings
Pediatric use
This medicine should not be used in children less than 2 years of age.
Drowsiness
Diphenhydramine should be used with caution due to the risk of drowsiness. It is advised that you do not perform activities like driving vehicles or operating heavy machinery after taking this medicine.
Phenylketonuria
Some diphenhydramine products may be sweetened with aspartame, which is a source of phenylalanine. Use of such products may cause mental retardation in patients with phenylketonuria. It is advised that you report all your medical conditions to the doctor before taking this medicine.
Pediatric use
In children less than 12 years of age, this medicine should not be used to induce sleep.
Missed Dose
Diphenhydramine is generally used as and when needed. If you are on a scheduled dose, take the missed dose as soon as you remember. If it is almost the time for the next dose, skip the missed dose. Do not double the dose to make up for the missed one.
Overdose
Seek emergency medical treatment or contact the doctor in case of an overdose.
All drugs interact differently for person to person. You should check all the possible interactions with your doctor before starting any medicine.
Interaction with Alcohol
Description
N/A
Instructions
Use of alcohol along with Diphenhydramine is not recommended since the combination increases the risk of side-effects like dizziness and drowsiness. It is advised that you do not perform any activities that require high mental alertness like driving a vehicle or operating machinery if you consume alcohol with this medicine.
Interaction with Medicine
Linezolid
Tamoxifen
Morphine
Antidepressants
CNS depressants
Disease interactions
Depression
Use of Diphenhydramine in patients with depression is not recommended since it may worsen the symptoms and may result in suicidal behavior or ideation. Patients with depression should be closely monitored for any changes in mood or behavior while receiving this medicine. Appropriate dose adjustments or replacement with a suitable alternative should be done under your doctor's supervision.
Renal and/or Liver diseases
Patients with renal and/or liver diseases may be at higher risk of adverse effects during the treatment with this medicine. Appropriate dose adjustments and monitoring of kidney and liver function may be required based on the clinical condition.
Food interactions
Information not available.
Lab interactions
Information not available.
Strictly follow the instructions on the label and take Diphenhydramine only as directed. Do not take more than the prescribed dose. It is advised that you should inform the doctor about all the medicines or herbal products that you are using and about all your medical conditions before taking this medicine. Use this medicine only for the prescribed purpose.
Miscelleneous
How it works
Diphenhydramine blocks the action of certain substances produced by the body which induces allergic reactions.
Legal Status
Classification
Category
Antihistamines
Schedule
Schedule G
Diphenhydramine: MedlinePlus Drug Information [Internet]. Medlineplus.gov. 2017 [cited 14 July 2017]. Available from:
DailyMed - Diphenhydramine hydrochloride capsule [Internet]. Dailymed.nlm.nih.gov. 2017 [cited 14 July 2017]. Available from:
[Internet]. 2017 [cited 14 July 2017]. Available from:
Diphenhydramine - DrugBank [Internet]. Drugbank.ca. 2017 [cited 14 July 2017]. Available from:
Diphenhydramine [Internet]. Snomedbrowser.com. 2017 [cited 14 July 2017]. Available from:
Information on this page was last updated on 8 Jan 2018
Disclaimer
We’ve made all possible efforts to ensure that the information provided here is accurate, up-to-date and complete, however, it should not be treated as a substitute for professional medical advice, diagnosis or treatment. Practo only provides reference source for common information on medicines and does not guarantee its accuracy or exhaustiveness. The absence of a warning for any drug or combination thereof, should not be assumed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Practo does not assume any responsibility for any aspect of healthcare administered with the aid of information provided above. If you have any doubts about your medication then we strongly recommend that you consult with your doctor, nurse or healthcare provider. See detailed T&C here.