Diphenhydramine
Uses of Diphenhydramine
Diphenhydramine is an antihistamine used to relieve allergy symptoms and short-term sleep difficulties.
It is commonly used for:
• Allergic reactions: Relieves sneezing, itching, and skin rashes caused by allergies.
• Hay fever: Eases nasal and eye symptoms caused by seasonal allergies.
• Motion sickness: Helps prevent and relieve nausea associated with motion sickness.
• Short-term insomnia: Used for its sedating effect to help with occasional sleeplessness.
• Cough: Used in combination products to help relieve dry cough associated with allergies or colds.
Side effects of Diphenhydramine
Drowsiness
Dizziness
Constipation
Stomach upset
Blurred vision
How Diphenhydramine works
Diphenhydramine works by blocking histamine, a chemical the body releases during an allergic reaction.
By blocking histamine (H1) receptors, it reduces symptoms such as sneezing, itching, and swelling caused by allergies.
Diphenhydramine also crosses into the brain more readily than newer antihistamines, producing a sedating effect that helps with sleep difficulties and reduces nausea associated with motion sickness.
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Doctor of Medicine
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BAMS, FMC, MD Resident
Expert Advice
Dosage Forms Available
Diphenhydramine is available in various forms for oral administration such as tablets, capsules, and liquid-filled capsules, dissolving strips, powder, chewable tablets, dissolving tablets and liquid that can be taken by mouth.
Age and Dose Restrictions
This medicine is used in adults, as well as children aged 2 years and above.
Contraindications
Diphenhydramine is contraindicated in patients with known hypersensitivity to it or any of its components.
It should not be used in patients with breathing problems, glaucoma, heart problems, high blood pressure, liver disease, seizures, stomach/intestinal problems, overactive thyroid or difficulty urinating.
Other Medications to Avoid
Diphenhydramine can interact with opioids (such as morphine and codeine), sleeping pills (such as zolpidem and eszopiclone), muscle relaxants (like baclofen and tizanidine) and other antihistamines (like cetirizine and fexofenadine).
Overdose and Missed Dose
Overdosing on Diphenhydramine may cause severe drowsiness, seizures or widened pupils. In children, restlessness and hallucinations may occur. We advise seeking immediate medical attention if such symptoms occur.
If you miss a dose of this medicine, take it as soon as you remember. However, do not double the dose to make up for a missed one.
Management of Side Effects
Most side effects are temporary and generally harmless; they resolve when discontinuing this medicine. However, if you experience any severe side effects let your doctor know.
Drinking plenty of water may help to manage some side effects like dry mouth and constipation.
If you experience drowsiness, you can try taking the medication before bedtime.
Use in Driving and Operating Machinery
Diphenhydramine may cause drowsiness or dizziness. Therefore, it is advisable to avoid driving or operating heavy machinery until you know how this medication impacts you.
Use in Pregnancy and Lactation
Use of Diphenhydramine during pregnancy should be considered only if the potential benefit justifies the potential risk to the foetus.
As it may pass into breast milk, nursing mothers should consult a doctor before using this medicine.
Caution in Other Conditions
Diphenhydramine should be used with caution in patients with liver or kidney disease as they may need dosage adjustments.
Individuals with cardiovascular disease should also exercise caution while using this medicine due to the possibility of increased heart rate.
Special Dietary and Lifestyle Recommendations
Maintaining a well-balanced diet can help manage symptoms of allergies, common cold, or hay fever that Diphenhydramine is used to relieve.
Regular sleep routines may help manage insomnia.
For patients who use this medicine to prevent motion sickness, it might be helpful to look straight ahead when travelling.
Frequently asked questions
Does Diphenhydramine provide relief from motion sickness?
Yes, Diphenhydramine is often used to prevent and manage symptoms of motion sickness such as nausea, vomiting, and dizziness.
Can Diphenhydramine affect my vision?
One of the side effects of Diphenhydramine can be blurred vision. It may also cause drowsiness, so it is advisable to avoid driving or operating machinery until you know how this medicine affects you.
Is Diphenhydramine a steroid?
No, Diphenhydramine is not a steroid; it is an antihistamine medicine used primarily for the management of allergies, hay fever, and common cold symptoms.
Can Diphenhydramine help me sleep better?
Yes, Diphenhydramine has sedating properties and is sometimes used as a short-term solution for insomnia or other sleep-related problems.
Will Diphenhydramine affect my mood?
Diphenhydramine can potentially cause mood changes as a side effect. These might include restlessness or confusion. If you notice such changes after taking this medicine, consult your doctor.
How long does the effect of Diphenhydramine last?
The effects of Diphenhydramine usually last for 4 to 6 hours. Therefore, it is commonly taken every 4 to 6 hours to manage symptoms effectively.
Is Diphenhydramine available over the counter or do I need a prescription?
Diphenhydramine is commonly available over the counter, but it is always advised to use it under the guidance of a doctor to ensure safe and effective usage.
Diphenhydramine in other salts
List of medicines for Diphenhydramine
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