Diphenhydramine 25mg/10ml Liquid
It is used to relieve coughing.It is used to ease allergy signs.It is used to help motion sickness.It is used to treat signs like Parkinson's disease caused by other health problems. It is used to treat sleep problems.
Drug Class
Antihistamine, Sedative-Hypnotic, Antiemetic
Pharmacologic Class
First-generation antihistamine; Ethanolamine derivative; H1-receptor antagonist
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Diphenhydramine is an antihistamine that helps relieve allergy symptoms like sneezing, runny nose, and itchy eyes. It can also make you feel sleepy, so it's sometimes used to help with insomnia or motion sickness. It works by blocking a natural substance in your body called histamine.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food, but if it causes stomach upset, take it with food to help minimize discomfort.
When taking the liquid form of this medication, measure your dose carefully using the measuring device that comes with the medication. If a measuring device is not provided, ask your pharmacist for one to ensure accurate dosing.
If you have phenylketonuria (PKU), consult with your doctor before taking this medication, as some products may contain phenylalanine.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Do not freeze your medication. Keep all medications in a safe location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you take this medication on a regular basis and miss a dose, take it as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
If you take this medication as needed, do not take it more frequently than directed by your doctor.
To ensure you get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food, but if it causes stomach upset, take it with food to help minimize discomfort.
When taking the liquid form of this medication, measure your dose carefully using the measuring device that comes with the medication. If a measuring device is not provided, ask your pharmacist for one to ensure accurate dosing.
If you have phenylketonuria (PKU), consult with your doctor before taking this medication, as some products may contain phenylalanine.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Do not freeze your medication. Keep all medications in a safe location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you take this medication on a regular basis and miss a dose, take it as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Avoid driving or operating heavy machinery until you know how this medication affects you, as it can cause drowsiness.
- Avoid alcohol and other sedating medications while taking diphenhydramine, as this can increase drowsiness and other side effects.
- To relieve dry mouth, suck on sugar-free candy or ice chips, or use artificial saliva.
- Take with food or milk if stomach upset occurs.
- Do not exceed the recommended dose.
Available Forms & Alternatives
Available Strengths:
- Diphenhydramine 50mg/ml Inj, 1ml
- Diphenhydramine Hcl 50mg Caps
- Diphenhydramine 50mg Capsules
- Diphenhydramine 12.5mg/5ml Elixir
- Diphenhydramine 25mg Tablets
- Diphenhydramine 25mg/10ml Liquid
- Diphenhydramine 12.5mg/5ml Liquid
- Diphenhydramine 12.5mg/5ml Liquid
- Diphenhydramine 25mg Caps
- Diphenhydramine 25mg Capsules
- Diphenhydramine 50mg/ml Inj, 1ml
- Diphenhydramine 25mg Tablets
- Diphenhydramine 25mg Capsules
Dosing & Administration
Adult Dosing
Standard Dose:
25-50 mg (10-20 mL) orally every 4-6 hours as needed
Dose Range:
25 - 50 mg
Condition-Specific Dosing:
Allergy/Cold Symptoms:
25-50 mg (10-20 mL) orally every 4-6 hours; Max 300 mg/day
Insomnia:
50 mg (20 mL) orally at bedtime
Motion Sickness:
25-50 mg (10-20 mL) orally 30 minutes before travel, then every 4-6 hours as needed
Extrapyramidal Symptoms (Drug-induced):
25-50 mg (10-20 mL) orally 3-4 times daily
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established (contraindicated in infants <2 years for cough/cold symptoms)
Child:
6 to <12 years: 12.5-25 mg (5-10 mL) orally every 4-6 hours; Max 150 mg/day. Not recommended for children <6 years for cough/cold symptoms.
Adolescent:
âĨ12 years: 25-50 mg (10-20 mL) orally every 4-6 hours; Max 300 mg/day
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended, but monitor for increased sedation.
Moderate:
Consider dose reduction or extended dosing interval (e.g., every 6-8 hours) due to potential for accumulation of parent drug and metabolites.
Severe:
Consider significant dose reduction (e.g., 25 mg every 8-12 hours) or extended dosing interval. Avoid if possible.
Dialysis:
Diphenhydramine is not significantly removed by hemodialysis. Administer after dialysis if needed, with caution.
Hepatic Impairment:
Mild:
No specific adjustment recommended.
Moderate:
Consider dose reduction (e.g., 25 mg every 6-8 hours) due to impaired metabolism.
Severe:
Consider significant dose reduction (e.g., 25 mg every 8-12 hours) or extended dosing interval. Avoid if possible.
Confidence:
Medium
Pharmacology
Mechanism of Action
Diphenhydramine is a first-generation antihistamine that competitively antagonizes H1 histamine receptors, preventing histamine from binding and exerting its effects. It also possesses significant anticholinergic (muscarinic), antiemetic, and sedative properties due to its ability to cross the blood-brain barrier and affect central H1 and muscarinic receptors.
Pharmacokinetics
Absorption:
Bioavailability:
40-60%
Tmax:
1-4 hours
FoodEffect:
Food may slightly delay absorption but does not significantly affect bioavailability.
Distribution:
Vd:
3.3-6.8 L/kg
ProteinBinding:
78-99%
CnssPenetration:
Yes
Elimination:
HalfLife:
2.4-9.3 hours (average 4-8 hours)
Clearance:
Not available
ExcretionRoute:
Urine (primarily as metabolites)
Unchanged:
<1%
Pharmacodynamics
OnsetOfAction:
15-60 minutes
PeakEffect:
1-3 hours
DurationOfAction:
4-6 hours
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Changes in balance
Feeling less alert or aware
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or drowsiness
Thickening of mucus in the nose or throat
Feeling nervous or excitable
Upset stomach or vomiting
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Changes in balance
Feeling less alert or aware
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or drowsiness
Thickening of mucus in the nose or throat
Feeling nervous or excitable
Upset stomach or vomiting
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe drowsiness or dizziness
- Difficulty urinating
- Blurred vision or eye pain
- Confusion or hallucinations
- Fast or irregular heartbeat
- Seizures
- Signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you are breastfeeding or plan to breastfeed, as you may need to avoid breastfeeding while taking this medication.
If the patient is a premature baby or newborn, as this form of the medication should not be given to them.
This is not an exhaustive list of all potential interactions with this medication. Therefore, it is crucial to discuss the following with your doctor and pharmacist:
All prescription and over-the-counter medications you are taking, including natural products and vitamins.
* Any existing health problems.
To ensure your safety, always verify with your doctor that it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you are breastfeeding or plan to breastfeed, as you may need to avoid breastfeeding while taking this medication.
If the patient is a premature baby or newborn, as this form of the medication should not be given to them.
This is not an exhaustive list of all potential interactions with this medication. Therefore, it is crucial to discuss the following with your doctor and pharmacist:
All prescription and over-the-counter medications you are taking, including natural products and vitamins.
* Any existing health problems.
To ensure your safety, always verify with your doctor that it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To minimize the risk of severe side effects, do not exceed the dosage prescribed by your doctor. Taking more than the recommended amount can increase your chance of experiencing severe side effects. Additionally, do not take this medication for a longer duration than specified by your doctor.
Until you understand how this medication affects you, avoid operating a vehicle or engaging in activities that require alertness.
Do not use this medication in conjunction with other products containing diphenhydramine. It is also recommended to avoid consuming alcohol while taking this drug.
Before using marijuana, other forms of cannabis, or prescription and over-the-counter (OTC) medications that may cause drowsiness, consult with your doctor.
Note that different brands of this medication may be suitable for children of varying ages. Therefore, it is crucial to consult with a doctor before administering this medication to a child. Furthermore, do not use this medication as a means to induce sleep in children; instead, discuss alternative options with your doctor.
If you are 60 years or older, exercise caution when using this medication, as you may be more susceptible to side effects. Similarly, when administering this medication to a child, use it with caution, as children may have a higher risk of experiencing excitability.
If you are pregnant or planning to become pregnant, inform your doctor, as it is necessary to discuss the benefits and risks associated with using this medication during pregnancy.
To minimize the risk of severe side effects, do not exceed the dosage prescribed by your doctor. Taking more than the recommended amount can increase your chance of experiencing severe side effects. Additionally, do not take this medication for a longer duration than specified by your doctor.
Until you understand how this medication affects you, avoid operating a vehicle or engaging in activities that require alertness.
Do not use this medication in conjunction with other products containing diphenhydramine. It is also recommended to avoid consuming alcohol while taking this drug.
Before using marijuana, other forms of cannabis, or prescription and over-the-counter (OTC) medications that may cause drowsiness, consult with your doctor.
Note that different brands of this medication may be suitable for children of varying ages. Therefore, it is crucial to consult with a doctor before administering this medication to a child. Furthermore, do not use this medication as a means to induce sleep in children; instead, discuss alternative options with your doctor.
If you are 60 years or older, exercise caution when using this medication, as you may be more susceptible to side effects. Similarly, when administering this medication to a child, use it with caution, as children may have a higher risk of experiencing excitability.
If you are pregnant or planning to become pregnant, inform your doctor, as it is necessary to discuss the benefits and risks associated with using this medication during pregnancy.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or deep sleep
- Dilated pupils
- Flushed skin
- Dry mouth and eyes
- Urinary retention
- Constipation
- Agitation, hallucinations, delirium (especially in children)
- Seizures
- Coma
- Respiratory depression
- Cardiac arrhythmias
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and may include activated charcoal, gastric lavage, and management of symptoms (e.g., benzodiazepines for seizures, physostigmine for severe anticholinergic toxicity).
Drug Interactions
Major Interactions
- CNS depressants (e.g., alcohol, opioids, benzodiazepines, sedatives, hypnotics, tricyclic antidepressants): Increased sedation and respiratory depression.
- Anticholinergics (e.g., atropine, scopolamine, tricyclic antidepressants, some antipsychotics): Increased anticholinergic effects (dry mouth, blurred vision, urinary retention, constipation, confusion).
Moderate Interactions
- MAO inhibitors (MAOIs): May prolong and intensify the anticholinergic and CNS depressant effects of diphenhydramine.
- Potassium chloride (oral): Increased risk of GI lesions due to anticholinergic effects slowing GI motility.
- Beta-2 agonists (e.g., albuterol): May reduce efficacy of beta-2 agonists due to anticholinergic effects on bronchial smooth muscle.
Minor Interactions
- Cholinesterase inhibitors (e.g., donepezil): May antagonize the effects of cholinesterase inhibitors.
- Metoclopramide: Antagonism of prokinetic effects.
Monitoring
Baseline Monitoring
Patient history (allergies, pre-existing conditions like glaucoma, BPH, asthma, cardiovascular disease)
Rationale: To identify contraindications or conditions where diphenhydramine should be used with caution.
Timing: Prior to initiation
Current medication list
Rationale: To identify potential drug-drug interactions, especially with CNS depressants or anticholinergics.
Timing: Prior to initiation
Routine Monitoring
Sedation level
Frequency: As needed, especially during initial use or dose changes
Target: Acceptable level of drowsiness for desired effect, without excessive impairment
Action Threshold: Excessive drowsiness, impaired coordination, or paradoxical excitation (especially in children/elderly)
Anticholinergic side effects (dry mouth, blurred vision, urinary retention, constipation)
Frequency: As needed, especially during initial use or dose changes
Target: Minimal to tolerable
Action Threshold: Severe or intolerable symptoms, or signs of urinary retention
Symptom Monitoring
- Drowsiness
- Dizziness
- Dry mouth
- Blurred vision
- Urinary retention
- Constipation
- Nausea
- Nervousness
- Paradoxical excitation (especially in children)
Special Patient Groups
Pregnancy
Generally considered low risk (Category B), but use only if clearly needed and potential benefits outweigh risks. Consult a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Limited data, but no clear evidence of teratogenicity.
Second Trimester:
Generally considered safe for occasional use.
Third Trimester:
Use with caution near term as it may cause irritability or drowsiness in the neonate.
Lactation
Excreted into breast milk. Not recommended for nursing mothers, especially with regular use, due to potential for infant drowsiness, irritability, and anticholinergic effects (e.g., decreased milk supply). Consider alternative antihistamines.
Infant Risk:
Moderate risk (L3) - potential for sedation, irritability, and anticholinergic effects in infant; theoretical risk of decreased milk supply.
Pediatric Use
Use with extreme caution in children, especially those under 2 years of age, due to increased risk of respiratory depression, paradoxical excitation, and anticholinergic effects. Not recommended for cough/cold symptoms in children under 6 years. Dosing must be precise and based on weight/age.
Geriatric Use
Increased sensitivity to anticholinergic effects (e.g., sedation, confusion, dry mouth, urinary retention, constipation) and increased risk of falls. Use lowest effective dose and avoid if possible, especially in patients with cognitive impairment, glaucoma, or benign prostatic hyperplasia (BPH). Consider alternative non-sedating antihistamines.
Clinical Information
Clinical Pearls
- Diphenhydramine is a first-generation antihistamine with significant sedative and anticholinergic properties. It is often used off-label for insomnia.
- Advise patients about potential for significant drowsiness and to avoid activities requiring mental alertness.
- Caution patients about additive CNS depression with alcohol or other sedatives.
- Be aware of anticholinergic side effects, especially in the elderly (e.g., urinary retention, constipation, confusion, dry mouth).
- Paradoxical excitation (restlessness, nervousness, insomnia) can occur, particularly in young children and sometimes in the elderly.
- Not recommended for long-term use for insomnia due to tolerance and potential for rebound insomnia upon discontinuation.
Alternative Therapies
- Second-generation antihistamines (e.g., loratadine, cetirizine, fexofenadine) for allergies (less sedating)
- Doxylamine (another sedating antihistamine) for insomnia
- Melatonin for insomnia
- Non-pharmacological interventions for insomnia (e.g., sleep hygiene)
- Meclizine or scopolamine for motion sickness
Cost & Coverage
Average Cost:
$5 - $20 per 120 mL bottle
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more details. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide information about the medication taken, the amount, and the time it happened.