Promethazine 50mg Tablets
WARNING: Children:Do not give this drug to a child younger than 2 years of age. It may cause very bad and sometimes deadly breathing problems.Use with care in children 2 years of age and older. Talk with the doctor.Before your child takes this drug, tell the doctor if your child is taking any drugs that can cause breathing problems. There are many drugs that can do this. Ask the doctor or pharmacist if you are not sure. @ COMMON USES: It is used to ease allergy signs.It is used to help motion sickness.It is used to manage pain.It is used to prevent upset stomach and throwing up from surgery.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antihistamine, Antiemetic, Sedative
Pharmacologic Class
Phenothiazine derivative, H1-receptor antagonist
Pregnancy Category
Category C
FDA Approved
Sep 1951
DEA Schedule
Not Controlled
Overview
What is this medicine?
Promethazine is a medication used to treat allergies, motion sickness, nausea and vomiting, and to help with sleep or to calm you before surgery. It works by blocking certain natural substances in your body that cause these symptoms. It can make you feel very sleepy.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, take it with food to help minimize this side effect. For motion sickness, take the medication 30 to 60 minutes before traveling.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. 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. Instead, check with your pharmacist for guidance on the best disposal method. You may also have access to drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular 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 use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, take it with food to help minimize this side effect. For motion sickness, take the medication 30 to 60 minutes before traveling.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. 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. Instead, check with your pharmacist for guidance on the best disposal method. You may also have access to drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular 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 significant drowsiness and impaired judgment.
- Avoid alcohol and other medications that cause drowsiness (e.g., pain relievers, sleeping pills, anxiety medications) while taking promethazine, as this can worsen sedation and respiratory depression.
- Avoid prolonged exposure to sunlight or tanning beds, as promethazine can increase sensitivity to the sun (photosensitivity). Use sunscreen and wear protective clothing.
- Stay hydrated to help manage dry mouth, a common side effect.
- If taking for motion sickness, take it 30-60 minutes before travel.
Available Forms & Alternatives
Available Strengths:
- Promethazine 25mg/ml Inj 1ml Amps
- Promethazine 50mg Suppositories
- Promethazine 12.5mg Suppositories
- Promethazine 25mg/ml Inj 1ml Vial
- Promethazine 50mg/ml Inj 25x1ml
- Promethazine 25mg Tablets
- Promethazine 50mg Tablets
- Promethazine 12.5mg Tablets
- Promethazine DM Syrup
- Promethazine 25mg Suppositories
- Promethazine VC Plain Syrup
- Promethazine DM Oral Solution
- Promethazine 6.25mg/5ml Syrup
- Promethazine DM Syrup
Dosing & Administration
Adult Dosing
Standard Dose:
For sedation/insomnia: 25-50 mg at bedtime. For severe allergic reactions or pre-operative sedation: 50 mg as a single dose. For nausea/vomiting: 25 mg initially, then 12.5-25 mg every 4-6 hours as needed.
Dose Range:
6.25 - 50 mg
Condition-Specific Dosing:
Allergy:
6.25-12.5 mg orally 3 times daily, or 25 mg at bedtime.
Nausea/Vomiting:
25 mg orally initially, then 12.5-25 mg every 4-6 hours as needed.
Sedation/Insomnia:
25-50 mg orally at bedtime.
Pre-operative Sedation:
25-50 mg orally as a single dose.
Pediatric Dosing
Neonatal:
Contraindicated in children younger than 2 years of age due to risk of fatal respiratory depression.
Infant:
Contraindicated in children younger than 2 years of age due to risk of fatal respiratory depression.
Child:
For children âĨ 2 years: 0.5 mg/kg/dose orally, usually given at bedtime or as a single dose for sedation/allergy. Max 25 mg/dose. For nausea/vomiting: 0.5 mg/kg/dose every 4-6 hours as needed, not to exceed 25 mg/dose or 1.1 mg/kg/day.
Adolescent:
Same as adult dosing, but generally start with lower end of adult range (e.g., 12.5-25 mg).
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended, use with caution.
Moderate:
Use with caution; consider lower doses or extended dosing intervals due to potential for accumulation of metabolites.
Severe:
Use with caution; consider lower doses or extended dosing intervals due to potential for accumulation of metabolites. Avoid if possible.
Dialysis:
Not significantly dialyzable. Use with caution; monitor for adverse effects.
Hepatic Impairment:
Mild:
No specific dose adjustment recommended, use with caution.
Moderate:
Use with caution; consider lower doses or extended dosing intervals due to extensive hepatic metabolism.
Severe:
Use with caution; consider lower doses or extended dosing intervals due to extensive hepatic metabolism. Avoid if possible.
Pharmacology
Mechanism of Action
Promethazine is a phenothiazine derivative that acts as a potent, first-generation H1-receptor antagonist. It competitively blocks histamine H1 receptors, thereby preventing the effects of histamine on capillaries, bronchi, and gastrointestinal smooth muscle. Its antiemetic effects are attributed to its anticholinergic and central antidopaminergic actions, blocking dopamine D2 receptors in the chemoreceptor trigger zone (CTZ). It also possesses significant anticholinergic (muscarinic receptor blockade) and sedative properties due to its ability to cross the blood-brain barrier and block H1 receptors in the CNS.
Pharmacokinetics
Absorption:
Bioavailability:
25-50% (due to extensive first-pass metabolism)
Tmax:
2-3 hours
FoodEffect:
Food may delay absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
131-177 L/kg (large volume of distribution)
ProteinBinding:
Approximately 93%
CnssPenetration:
Yes
Elimination:
HalfLife:
10-14 hours (range 7-19 hours)
Clearance:
Not available (highly variable)
ExcretionRoute:
Primarily renal (urine) as metabolites, small amount in feces.
Unchanged:
<1% (in urine)
Pharmacodynamics
OnsetOfAction:
20 minutes (oral)
PeakEffect:
2-3 hours
DurationOfAction:
4-6 hours (up to 12 hours for sedative effects)
Safety & Warnings
BLACK BOX WARNING
RESPIRATORY DEPRESSION: Promethazine should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. Postmarketing cases of respiratory depression, including fatalities, have been reported with use of promethazine in pediatric patients less than 2 years of age. Caution should be exercised when administering promethazine to pediatric patients 2 years of age and older. It is recommended that the lowest effective dose of promethazine be used in pediatric patients 2 years of age and older and to avoid concomitant administration of other drugs with respiratory depressant effects.
Side Effects
Serious Side Effects: Seek Medical Help Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
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
Signs of high or low blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Abnormal heart rhythms, such as:
+ Fast or slow heartbeat
Neurological symptoms, including:
+ Trouble controlling body movements
+ Twitching
+ Changes in balance
+ Difficulty swallowing or speaking
+ Shakiness
+ Trouble moving around
+ Stiffness
Confusion or altered mental status
Feeling nervous or excitable
Hallucinations (seeing or hearing things that are not there)
Mood changes
Ringing in the ears
Seizures
Unexplained bruising or bleeding
Yellowing of the skin or eyes
Changes in eyesight
Neuroleptic malignant syndrome (NMS), a potentially life-threatening condition, characterized by:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Changes in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Severe breathing problems, including:
+ Slow, shallow, or difficulty breathing
Low white blood cell counts, which may increase the risk of infection, characterized by:
+ Fever
+ Chills
+ Sore throat
Other Side Effects
Most people experience few or no side effects while taking this medication. However, some people may experience mild side effects, including:
Dizziness
Drowsiness
Fatigue
Weakness
Blurred vision
Dry mouth
Upset stomach or vomiting
Trouble sleeping
* Stuffy nose
If any of these side effects or any other symptoms bother you or do not go away, contact your doctor or seek medical attention. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
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
Signs of high or low blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Abnormal heart rhythms, such as:
+ Fast or slow heartbeat
Neurological symptoms, including:
+ Trouble controlling body movements
+ Twitching
+ Changes in balance
+ Difficulty swallowing or speaking
+ Shakiness
+ Trouble moving around
+ Stiffness
Confusion or altered mental status
Feeling nervous or excitable
Hallucinations (seeing or hearing things that are not there)
Mood changes
Ringing in the ears
Seizures
Unexplained bruising or bleeding
Yellowing of the skin or eyes
Changes in eyesight
Neuroleptic malignant syndrome (NMS), a potentially life-threatening condition, characterized by:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Changes in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Severe breathing problems, including:
+ Slow, shallow, or difficulty breathing
Low white blood cell counts, which may increase the risk of infection, characterized by:
+ Fever
+ Chills
+ Sore throat
Other Side Effects
Most people experience few or no side effects while taking this medication. However, some people may experience mild side effects, including:
Dizziness
Drowsiness
Fatigue
Weakness
Blurred vision
Dry mouth
Upset stomach or vomiting
Trouble sleeping
* Stuffy nose
If any of these side effects or any other symptoms bother you or do not go away, contact your doctor or seek medical attention. 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 difficulty waking up
- Slow, shallow, or difficult breathing
- Unusual muscle movements, stiffness, or tremors (especially in the face, neck, or back)
- Hallucinations or confusion
- Seizures
- Yellowing of the skin or eyes (jaundice)
- Severe dizziness or fainting
- Fast or irregular heartbeat
- Difficulty urinating
- Vision changes or eye pain
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, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have respiratory conditions, including asthma, chronic obstructive pulmonary disease (COPD), sleep apnea, or other breathing problems.
If you have liver problems or a history of Reye's syndrome.
This list is not exhaustive, and it is crucial to discuss all your health problems and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
Your health problems, both past and present
Before making any changes to your medication regimen, including starting, stopping, or adjusting the dose of any medication, consult with your doctor to confirm it is safe to do so.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have respiratory conditions, including asthma, chronic obstructive pulmonary disease (COPD), sleep apnea, or other breathing problems.
If you have liver problems or a history of Reye's syndrome.
This list is not exhaustive, and it is crucial to discuss all your health problems and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
Your health problems, both past and present
Before making any changes to your medication regimen, including starting, stopping, or adjusting the dose of any medication, consult with your doctor to confirm it is safe to do so.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Before operating a vehicle or engaging in any activity that requires alertness and clear vision, wait until you understand how this medication affects you.
This drug may interfere with the accuracy of certain pregnancy tests. If you are pregnant or suspect you may be pregnant, consult your doctor.
If you have diabetes, it is crucial to closely monitor your blood sugar levels while taking this medication.
Prior to consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that may impair your reactions, discuss the potential risks with your doctor.
You may be more susceptible to sunburn while taking this medication. To minimize this risk, avoid exposure to direct sunlight, sunlamps, and tanning beds, and use protective measures such as sunscreen, clothing, and eyewear that provide adequate sun protection.
This medication may increase the risk of seizures, particularly in individuals with a history of seizure disorders. Consult your doctor to determine if you are at a higher risk of experiencing seizures while taking this medication.
If you are 65 years or older, exercise caution when taking this medication, as you may be more prone to experiencing side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is necessary to discuss the potential benefits and risks of this medication to both you and your baby.
Before operating a vehicle or engaging in any activity that requires alertness and clear vision, wait until you understand how this medication affects you.
This drug may interfere with the accuracy of certain pregnancy tests. If you are pregnant or suspect you may be pregnant, consult your doctor.
If you have diabetes, it is crucial to closely monitor your blood sugar levels while taking this medication.
Prior to consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that may impair your reactions, discuss the potential risks with your doctor.
You may be more susceptible to sunburn while taking this medication. To minimize this risk, avoid exposure to direct sunlight, sunlamps, and tanning beds, and use protective measures such as sunscreen, clothing, and eyewear that provide adequate sun protection.
This medication may increase the risk of seizures, particularly in individuals with a history of seizure disorders. Consult your doctor to determine if you are at a higher risk of experiencing seizures while taking this medication.
If you are 65 years or older, exercise caution when taking this medication, as you may be more prone to experiencing side effects.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is necessary to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or coma
- Respiratory depression (slow, shallow breathing)
- Hypotension (low blood pressure)
- Tachycardia (fast heart rate)
- Anticholinergic effects (dilated pupils, dry mouth, flushed skin, fever, urinary retention, absent bowel sounds)
- Agitation, hallucinations, delirium (especially in children)
- Seizures
- Cardiovascular collapse
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive, including maintaining airway, breathing, and circulation. Naloxone may be considered if opioid co-ingestion is suspected. Physostigmine may be used for severe anticholinergic symptoms but carries risks.
Drug Interactions
Contraindicated Interactions
- MAO inhibitors (concurrent use or within 14 days of MAOI discontinuation) - may prolong and intensify anticholinergic and CNS depressant effects.
- Other phenothiazines (concurrent use) - increased risk of adverse effects.
Major Interactions
- CNS depressants (e.g., alcohol, opioids, benzodiazepines, barbiturates, tricyclic antidepressants, other antihistamines) - additive CNS depression, respiratory depression, profound sedation.
- Anticholinergic drugs (e.g., atropine, scopolamine, tricyclic antidepressants, some antipsychotics) - additive anticholinergic effects (dry mouth, blurred vision, urinary retention, constipation, confusion).
- QT-prolonging drugs (e.g., Class IA and III antiarrhythmics, some antipsychotics, macrolide antibiotics) - theoretical risk of additive QT prolongation, though less prominent than other phenothiazines.
- Dopamine agonists (e.g., bromocriptine, cabergoline) - promethazine's antidopaminergic effects may antagonize their therapeutic effects.
- Epinephrine - promethazine may reverse the vasopressor effect of epinephrine, leading to a further decrease in blood pressure.
Moderate Interactions
- Antihypertensives - additive hypotensive effects.
- Metoclopramide - increased risk of extrapyramidal symptoms.
- Antacids/Kaolin-pectin - may decrease absorption of promethazine (separate administration by at least 1 hour).
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Patient's medical history (especially respiratory, cardiac, neurological conditions)
Rationale: To identify contraindications or risk factors for adverse effects (e.g., respiratory depression, seizures, cardiovascular issues).
Timing: Prior to initiation of therapy.
Baseline vital signs (heart rate, blood pressure, respiratory rate)
Rationale: To establish baseline and monitor for hypotensive or respiratory depressant effects.
Timing: Prior to initiation of therapy.
Mental status assessment (level of consciousness, orientation)
Rationale: To assess baseline sedation and cognitive function.
Timing: Prior to initiation of therapy.
Routine Monitoring
Level of consciousness/Sedation
Frequency: Regularly, especially after initial doses or dose changes.
Target: Appropriate level of sedation for indication, without excessive drowsiness or unresponsiveness.
Action Threshold: Excessive sedation, somnolence, or difficulty arousing patient; consider dose reduction or discontinuation.
Respiratory rate and effort
Frequency: Regularly, especially in pediatric patients and those with respiratory compromise.
Target: Within normal limits for age, unlabored breathing.
Action Threshold: Bradypnea, shallow breathing, signs of respiratory distress; immediate medical attention required.
Blood pressure and heart rate
Frequency: Periodically, especially in patients at risk for hypotension.
Target: Within patient's normal range.
Action Threshold: Significant orthostatic hypotension or sustained hypotension; consider dose reduction or discontinuation.
Signs of anticholinergic effects (dry mouth, blurred vision, urinary retention, constipation)
Frequency: Regularly, especially in elderly patients.
Target: Minimal to tolerable symptoms.
Action Threshold: Severe or intolerable anticholinergic symptoms; consider dose reduction or alternative.
Signs of extrapyramidal symptoms (EPS) (e.g., dystonia, akathisia, parkinsonism)
Frequency: Periodically, especially with higher doses or prolonged use.
Target: Absence of EPS.
Action Threshold: Development of EPS; consider discontinuation or alternative.
Symptom Monitoring
- Excessive drowsiness or sedation
- Difficulty breathing or shallow breathing
- Dizziness or lightheadedness (especially when standing)
- Dry mouth, blurred vision, difficulty urinating, constipation
- Involuntary muscle movements, tremors, restlessness (akathisia), muscle stiffness (dystonia)
- Confusion or disorientation (especially in elderly)
- Skin rash or itching (allergic reaction)
- Yellowing of skin or eyes (jaundice, rare)
Special Patient Groups
Pregnancy
Promethazine is classified as Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Limited human data; animal studies show some adverse effects at high doses. Use only if clearly needed.
Second Trimester:
Generally considered safer than first trimester, but still use with caution.
Third Trimester:
Use near term may cause respiratory depression, extrapyramidal symptoms, or withdrawal symptoms in the neonate, especially if used in high doses or for prolonged periods. Avoid use during labor and delivery if possible.
Lactation
Promethazine is excreted into breast milk. The American Academy of Pediatrics considers it to be a drug for which the effect on the nursing infant is unknown but may be of concern. Lactation Risk Category L3 (Moderate Concern).
Infant Risk:
Potential for sedation, irritability, paradoxical excitation, and respiratory depression in the infant. Use with caution, monitor infant for drowsiness or unusual behavior. Consider alternative agents, especially in preterm or jaundiced infants, or if other CNS depressants are used concurrently by the mother.
Pediatric Use
Contraindicated in children younger than 2 years of age due to the risk of fatal respiratory depression. Use with extreme caution in children 2 years of age and older, using the lowest effective dose. Children are more susceptible to paradoxical excitation (restlessness, agitation, nightmares) and extrapyramidal symptoms.
Geriatric Use
Elderly patients are more susceptible to the anticholinergic effects (e.g., dry mouth, blurred vision, urinary retention, constipation, confusion) and CNS depressant effects (e.g., sedation, dizziness, orthostatic hypotension) of promethazine. Use with caution, starting with lower doses and titrating slowly. Avoid in elderly patients with dementia or cognitive impairment due to increased risk of delirium and falls. Consider Beers Criteria recommendations.
Clinical Information
Clinical Pearls
- Promethazine 50mg is a high dose, typically reserved for severe symptoms or single-dose sedation/pre-op use. Lower doses (e.g., 12.5mg, 25mg) are more common for routine allergy or nausea.
- Always confirm patient age before administering, especially in pediatric settings, due to the black box warning for children under 2 years.
- Educate patients about the significant sedative effects and the importance of avoiding alcohol and other CNS depressants.
- Monitor for anticholinergic side effects, particularly in the elderly, and advise on management (e.g., sugar-free candies for dry mouth).
- Be aware of the potential for paradoxical excitation in children and the elderly.
- Promethazine can interfere with pregnancy tests (false positive or negative) and glucose tolerance tests.
Alternative Therapies
- For Nausea/Vomiting: Ondansetron (Zofran), Granisetron (Kytril), Metoclopramide (Reglan), Dimenhydrinate (Dramamine), Diphenhydramine (Benadryl).
- For Allergy: Other H1-antihistamines (e.g., Diphenhydramine, Loratadine, Cetirizine, Fexofenadine).
- For Sedation/Insomnia: Diphenhydramine, Zolpidem (Ambien), Eszopiclone (Lunesta), Trazodone.
- For Motion Sickness: Scopolamine patch, Meclizine (Antivert), Dimenhydrinate.
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (25mg or 50mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (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 information. If you have any questions or concerns about your 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 emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it occurred.