Promethazine
Promethazine is a first-generation antihistamine that provides relief from allergic reactions, itching, and skin conditions like dermatitis. It also possesses antiemetic properties, making it effective for preventing and treating nausea, vomiting, and motion sickness, while its sedative effects make it useful for pre-procedural sedation.
A sedating antihistamine used for allergies, nausea, and motion sickness, with additional sedative properties.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- D04AA10
- RxNorm
- 8745
- Generic
- Promethazine
- Class
- atc-d04
- Brands
- Phenergan, Promethegan, Phenadoz
- Availability
- rx
- Lactation
- unknown
- Routes
- oral, rectal
- Forms
- injection, suspension, solution, capsule, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 25mg every 4-6 hours
- Maximum
- consult physician
- Frequency
- as needed, not exceeding 50mg daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 0.5mg per lb
- Maximum
- consult physician
- Frequency
- every 4-6 hours as needed
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 25mg at bedtime
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
11 groupspregnancy
first trimesteravoid if possible
use only if benefits outweigh potential risks to fetus
regular prenatal checkups
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
avoid prolonged use, use only when needed
fetal monitoring if used long-term
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid near term
avoid use close to delivery due to potential respiratory depression in newborn
monitor newborn for sedation and respiratory depression
Use with caution and monitor for adverse effects.
lactation
breastfeedingcontraindicated
do not use during breastfeeding - drug passes into breast milk
N/A
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
under 2 yearsdo not use
contraindicated due to risk of fatal respiratory depression
N/A
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
2 years and olderweight-based dosing, avoid high doses
use with extreme caution, not for sedation in children
monitor for respiratory depression
Use with caution and monitor for adverse effects.
geriatric
elderlystart with lower dose, reduce dose by 25-50%
use with caution due to increased sensitivity to anticholinergic effects
monitor for confusion, sedation, falls, constipation
Use with caution and monitor for adverse effects.
renal_impairment
mildno significant adjustment needed
monitor renal function
periodic renal function monitoring
Use with caution and monitor for adverse effects.
renal_impairment
moderate to severereduce dose by 50%
use with caution, dose reduction recommended
regular monitoring of renal function and drug levels
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderatereduce dose by 50%
use with caution, metabolized in liver
monitor liver function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
severeavoid use
contraindicated in severe hepatic impairment
N/A
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
Commonly prescribed since
General prescribing information for Promethazine products including Phenergan, Promethegan, and Phenadoz
Drug class
ATC classification as antihistamine agent
Common uses
Primary therapeutic applications approved for Promethazine
Available formulations
Dosage forms available for Promethazine
Treatment of allergic conditions including rhinitis, conjunctivitis, and dermatologic reactions; prevention and treatment of nausea, vomiting, and vertigo associated with motion sickness; pre- and post-operative sedation; as an adjunct to analgesics for enhanced pain relief.
Blocks histamine H1 receptors, reducing allergic symptoms such as itching, sneezing, and runny nose. Its antiemetic effect is attributed to action on the vomiting center in the brainstem, while sedation occurs through central nervous system depression.
May cause significant drowsiness and should be avoided when operating machinery. Contraindicated in children under 2 years due to risk of respiratory depression. Can cause photosensitivity reactions. Avoid concurrent use with alcohol or other CNS depressants. Anticholinergic effects may occur.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 24, 2026. · Read our editorial policy