Promethazine
Administration
- Type: Antiemetic; Phenothiazine Derivative; Sedative
- Dosage Forms: 12.5mg, 25mg, 50mg; 6.25mg/5 mL sol; IM; IV
- Routes of Administration: Oral
- Common Trade Names: Phenadoz; Phenergan; Promethegan
Adult Dosing
- Allergic conditions: 6.25-12.5mg PO tid
- May give additional dose of 12.5-25mg PO qhs
- Nausea/vomiting: 12.5-25mg PO/IM/IV q4-6h
- Max: 50mg/dose PO/IM; 25mg/dose IV
- IM preferred over IV
- Motion sickness: 25mg PO bid
- Start: 0.5-1h prior to travel
- Sedation: 25-50mg PO/IM/IV x1
- Max: 50mg/dose PO/IM; 25mg/dose IV
- IM preferred over IV
Pediatric Dosing
Only Approved for >2 years
- Allergic conditions: 0.1mg/kg PO q6h
- Max: 12.5mg/dose during day, 25mg/dose qhs
- May give additional dose of up to 0.5mg/kg PO qhs
- Use lowest effective dose
- Avoid other resp. depressants
- Nausea/vomiting: 0.25-1mg/kg PO/IM/IV q4-6h PRN;
- Max: 25mg/dose
- Motion sickness: 0.5mg/kg PO q12h PRN; Start: 0.5-1h before travel
- Max: 25mg/dose; Info: use lowest effective dose
- Avoid other resp. depressants
- Sedation: 12.5-25mg PO/IM/IV x1
- Max: 25mg/dose
- IM preferred over IV
- Use lowest effective dose
- Avoid other resp. depressants
Special Populations
Renal Dosing
- No adjustment
Hepatic Dosing
- Caution advised with hepatic impairment
Contraindications
- Hypersensitivity to drug/component
- Patients <2 yo
- Comatose patients
- Respiratory depression
- SC injection
- intra- or periarterial administration
Adverse Reactions
Serious
- extravasation/tissue damage (IV use > IM use)
- apnea
- respiratory depression
- respiratory depression, fatal (infants)
- seizures
- leukopenia
- thrombocytopenia
- agranulocytosis
Common
- drowsiness
- sedation
- blurred vision
- dizziness
- confusion
- disorientation
Pharmacology
- Half-life: 7-14 hrs
- Metabolism: urine, feces
- Excretion: CYP450
Mechanism of Action
- nonselective antagonist of central and peripheral H1 receptors; anticholinergic
See Also
References
<UpToDate, Micromedex>