Promethazine hydrochloride is available as a 25 or 50-mg/mL injection solution in 1-mL vials or ampuls.1515; 1516 Each mL contains promethazine hydrochloride 25 or 50 mg, disodium edetate 0.1 mg, calcium chloride 0.04 mg, sodium metabisulfite 0.25 mg, phenol 5 mg, and acetic acid-sodium acetate buffer in water for injection.1515; 1516
pH
Osmolality
The osmolality of promethazine hydrochloride 25 mg/mL was determined to be 291 mOsm/kg.1233
Promethazine hydrochloride is administered preferably by deep intramuscular injection.1515; 1516 Intra-arterial or subcutaneous injection is contraindicated.1515; 1516
If intramuscular injection is not possible, promethazine hydrochloride may be administered by intravenous infusion following dilution in sodium chloride 0.9% to a concentration not exceeding 1 mg/mL.1516 Infusion solutions other than sodium chloride 0.9% should not be used.1516 The diluted solution should be infused over 20 to 40 minutes through an intravenous catheter inserted in a large vein and preferably through a central venous catheter.1516 Recommended dilution volumes and maximum infusion rates are listed in Table 1.1516 The drug must not be infused through intravenous catheters placed into veins in the hand or wrist.1516 Extravasation should be avoided because severe tissue injury, including gangrene, can occur.1515; 1516 Intravenous administration is contraindicated at concentrations greater than 1 mg/mL.1516
Table 1. Dilution and Administration of Promethazine Hydrochloride Injection for Intravenous Infusion1516
| Patient Population | Dose of Promethazine Hydrochloride Injection | Volume of Sodium Chloride 0.9% for Dilution | Maximum Infusion Rate |
|---|---|---|---|
| Adults | 12.5 mg 25 mg 50 mg 75 mg | 50 mL 50 mL 50 mL 100 mL | 2.5 mL/min 2.5 mL/min 2.5 mL/min 5 mL/min |
| Pediatric Patients =2 years of age | 25 mg 25 to 50 mg | 25 mL 50 mL | 1.25 mL/min 1.25 mL/min |
Intact vials and ampuls should be stored at controlled room temperature and in the original cartons to protect from light.1515; 1516 Promethazine hydrochloride injection is a clear, colorless solution.1515; 1516 Inspect prior to use; discard if particulate matter or discoloration is observed.1515 Diluted solutions for infusion may be stored up to 4 hours at 20 to 25°C or up to 24 hours at 2 to 8°C.1516
Promethazine hydrochloride exhibits increasing stability with decreasing pH.1072
Syringes
Promethazine hydrochloride 25 mg/mL repackaged in 3-mL amber glass syringes (Hy-Pod) and stored at 25°C exhibited no changes in pH or appearance over 360 days. A possible reduction in concentration to 95% of initial was noted.535
Sorption
Promethazine hydrochloride (May & Baker) 8 mg/L in sodium chloride 0.9% (Travenol) in polyvinyl chloride (PVC) bags exhibited only about 5% sorption to the plastic during 1 week of storage at room temperature (15 to 20°C). However, when the solution was buffered from its initial pH of 5 to 7.4, approximately 59% of the drug was lost in 1 week due to sorption.536
In another study, promethazine hydrochloride (May & Baker) 8 mg/L in sodium chloride 0.9% exhibited a cumulative 22% loss due to sorption during a 7-hour simulated infusion through an infusion set (Travenol) consisting of a cellulose propionate burette chamber and 170 cm of PVC tubing. Both the burette and the tubing contributed to the loss. The extent of sorption was found to be independent of concentration.606
The drug was also tested as a simulated infusion over at least 1 hour by a syringe pump system. A glass syringe on a syringe pump was fitted with 20 cm of polyethylene tubing or 50 cm of Silastic tubing. Only 5% of the drug was lost with the polyethylene tubing, but a cumulative loss of 72% occurred during the 1-hour infusion through the Silastic tubing.606
A 25-mL aliquot of promethazine hydrochloride (May & Baker) 8 mg/L in sodium chloride 0.9% was stored in all-plastic syringes composed of polypropylene barrels and polyethylene plungers for 24 hours at room temperature in the dark. No loss due to sorption occurred.606
Central Venous Catheter
Promethazine hydrochloride (Schein) 2 mg/mL in dextrose 5% was found to be compatible with the ARROWg+ard Blue Plus (Arrow International) chlorhexidine-bearing triple-lumen central catheter. Essentially complete delivery of the drug was found with little or no drug loss occurring. Furthermore, chlorhexidine delivered from the catheter remained at trace amounts with no substantial increase due to the delivery of the drug through the catheter.2335
Drugs in Syringe Compatibility
Y-Site Injection Compatibility (1:1 Mixture)
Additional Compatibility Information
Chlorpromazine and Meperidine
Chlorpromazine hydrochloride, meperidine hydrochloride, and promethazine hydrochloride combined as an extemporaneous mixture for preoperative sedation, developed a brownish-yellow color after 2 weeks of storage with protection from light. The discoloration was attributed to the metacresol preservative content of the meperidine hydrochloride product used. Use of meperidine hydrochloride which contains a different preservative resulted in a solution that remained clear and colorless for at least 3 months when protected from light.1148
For a list of references cited in the text of this monograph, search the monograph titled References.