Promethazine 25mg Tablets
Overview
What is this medicine?
How to Use This Medicine
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. If you're using this medication to prevent motion sickness, take it 30 to 60 minutes before traveling.
Storing and Disposing of Your Medication
Store this medication at room temperature, away from light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in the 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 by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or participate in a drug take-back program 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, follow your doctor's instructions and do not take it more frequently than recommended.
Lifestyle & Tips
- Avoid alcohol and other medications that cause drowsiness (e.g., pain relievers, sleeping pills) while taking promethazine, as this can increase sedation and breathing problems.
- Do not drive or operate heavy machinery until you know how this medication affects you, as it can cause significant drowsiness and dizziness.
- Avoid prolonged exposure to sunlight or tanning beds, as promethazine can make your skin more sensitive to the sun.
- Stay hydrated to help with dry mouth, a common side effect.
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
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
BLACK BOX WARNING
Side Effects
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice 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
+ 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 disorientation
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 rare but potentially life-threatening condition called NMS may occur. Seek medical help immediately if you experience:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Changes in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Respiratory Problems: This medication may cause severe and potentially life-threatening breathing problems. Seek medical help immediately if you experience:
+ Slow, shallow, or troubled breathing
Low White Blood Cell Count: This medication may increase the risk of infection due to a low white blood cell count. Seek medical help immediately if you experience:
+ Signs of infection, such as:
- Fever
- Chills
- Sore throat
Other Side Effects
Most people do not experience serious side effects, and many side effects are mild and temporary. However, if you experience any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
+ Dizziness
+ Drowsiness
+ Fatigue
+ Weakness
+ Blurred vision
+ Dry mouth
+ Upset stomach or vomiting
+ Trouble sleeping
+ Stuffy nose
Reporting Side Effects
If you have questions or concerns about side effects, contact 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 difficulty waking up
- Slow or shallow breathing
- Confusion or hallucinations
- Uncontrolled muscle movements (tremors, twitching, stiffness)
- Yellowing of the skin or eyes (jaundice)
- Unusual bleeding or bruising
- Sore throat, fever, or chills (signs of infection)
- Seizures
- Severe dizziness or fainting
- Difficulty urinating
Before Using This Medicine
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 conditions and medications with your doctor.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
Any health problems you have
Do not start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so in conjunction with this medication.
Precautions & Cautions
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 concerned about this, discuss it with 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 cause drowsiness, consult 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. 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, paralytic ileus)
- Extrapyramidal symptoms (involuntary movements)
- Seizures
- Cardiovascular collapse
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic, 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 is rarely recommended due to potential for adverse effects.
Drug Interactions
Contraindicated Interactions
Major Interactions
- CNS depressants (e.g., opioids, benzodiazepines, barbiturates, alcohol, tricyclic antidepressants, other antihistamines) - additive CNS depression, respiratory depression, profound sedation.
- Anticholinergic drugs (e.g., atropine, scopolamine, tricyclic antidepressants) - additive anticholinergic effects (dry mouth, blurred vision, urinary retention, constipation, paralytic ileus).
- QT-prolonging drugs (e.g., antiarrhythmics, certain antipsychotics, macrolide antibiotics) - theoretical risk of QT prolongation and torsades de pointes (though promethazine's direct effect on QT is minor, caution is advised).
- Dopamine agonists (e.g., bromocriptine, cabergoline) - promethazine's antidopaminergic effects may antagonize their therapeutic effects.
- Epinephrine - promethazine's alpha-adrenergic blocking effects may reverse the pressor effect of epinephrine, leading to further blood pressure decrease.
Moderate Interactions
- Antihypertensives - additive hypotensive effects.
- Cholinergic inhibitors (e.g., donepezil, rivastigmine) - promethazine's anticholinergic effects may reduce the efficacy of these drugs.
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine) - may increase promethazine plasma concentrations, leading to increased sedation and adverse effects.
- Phenytoin - promethazine may increase phenytoin levels.
Minor Interactions
- Not readily available
Monitoring
Baseline Monitoring
Rationale: To identify contraindications or risk factors for adverse effects (e.g., respiratory depression, seizures, cardiovascular issues).
Timing: Prior to initiation of therapy.
Rationale: To identify potential drug-drug interactions, especially with CNS depressants or anticholinergic agents.
Timing: Prior to initiation of therapy.
Routine Monitoring
Frequency: Regularly, especially during initial therapy or dose adjustments.
Target: Appropriate for therapeutic goal (e.g., mild sedation for sleep, alert for allergy).
Action Threshold: Excessive drowsiness, somnolence, or unresponsiveness; consider dose reduction or discontinuation.
Frequency: Regularly, especially in pediatric patients or those with respiratory compromise.
Target: Normal for age.
Action Threshold: Bradypnea, shallow breathing, or signs of respiratory distress; discontinue and provide respiratory support.
Frequency: Daily, or as symptoms arise.
Target: Absence or mild, tolerable symptoms.
Action Threshold: Severe or intolerable symptoms; consider dose reduction or alternative therapy.
Frequency: Periodically, especially with higher doses or prolonged use.
Target: Absence of symptoms.
Action Threshold: Tremor, dystonia, akathisia, rigidity, fever, altered mental status; discontinue immediately and manage symptomatically.
Symptom Monitoring
- Excessive drowsiness or sedation
- Difficulty breathing or shallow breathing
- Dizziness or lightheadedness
- Blurred vision
- Dry mouth
- Difficulty urinating
- Constipation
- Involuntary muscle movements (tremors, twitching)
- Restlessness or agitation
- Confusion or disorientation
- Yellowing of skin or eyes (jaundice)
- Unusual bleeding or bruising
- Sore throat or fever (signs of blood dyscrasias)
Special Patient Groups
Pregnancy
Category C. Use only if the potential benefit justifies the potential risk to the fetus. Promethazine has been used in pregnancy for nausea and vomiting, but data are limited. Avoid use in late third trimester due to potential for platelet aggregation inhibition in the neonate and increased risk of respiratory depression.
Trimester-Specific Risks:
Lactation
L3 (Moderate Risk). Promethazine is excreted into breast milk. Due to the potential for sedation, respiratory depression, and anticholinergic effects in the infant, use with caution. Monitor infant for drowsiness, poor feeding, and breathing difficulties. Consider alternative agents, especially in preterm or jaundiced infants.
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, and only when clearly indicated. Avoid concomitant use with other respiratory depressants. May cause paradoxical excitation in some children.
Geriatric Use
Increased susceptibility to anticholinergic effects (e.g., dry mouth, blurred vision, urinary retention, constipation), sedation, dizziness, and hypotension. Start with lower doses and titrate slowly. Increased risk of falls. Avoid in elderly patients with dementia-related psychosis due to increased mortality risk (off-label use). Consider Beers Criteria recommendations.
Clinical Information
Clinical Pearls
- Promethazine is a potent sedative; warn patients about impaired driving and operating machinery.
- Due to the black box warning, never administer to children under 2 years of age.
- Oral route is preferred. If IV administration is absolutely necessary, dilute extensively and administer slowly into a large, patent vein to minimize risk of severe tissue injury (gangrene). Subcutaneous injection is contraindicated.
- Can cause paradoxical excitation (restlessness, agitation) in some children and occasionally adults.
- Has significant anticholinergic side effects; caution in patients with glaucoma, prostatic hypertrophy, or urinary retention.
- May interfere with pregnancy tests (false positive or negative) and glucose tolerance tests.
Alternative Therapies
- For allergy: Diphenhydramine, Loratadine, Cetirizine, Fexofenadine
- For nausea/vomiting: Ondansetron, Metoclopramide, Prochlorperazine
- For sedation/insomnia: Diphenhydramine, Zolpidem, Trazodone
- For motion sickness: Scopolamine (patch), Dimenhydrinate