AHFS Class:

56:28.12 Histamine H2-Antagonists

Generic Name

• Famotidine

Famotidine is available as a 10-mg/mL concentrate for injection in 2-mL single-dose vials and 4- and 20-mL multiple-dose vials.³⁸⁹⁷ Each mL of the concentrate also contains L-aspartic acid 4 mg and mannitol 20 mg in water for injection³⁸⁹⁷ Multiple-dose vials also contain benzyl alcohol 0.9%.³⁸⁹⁷ The concentrate must be diluted prior to administration.³⁸⁹⁷

Famotidine is also available as a premixed, ready-to-use solution for infusion in single-dose Galaxy plastic containers containing famotidine 20 mg in 50 mL.³⁸⁹⁸ Each 50 mL of solution also contains L-aspartic acid 6.8 mg and sodium chloride 450 mg in water for injection.³⁸⁹⁸ Additional L-aspartic acid or sodium hydroxide may be added to adjust the pH.³⁸⁹⁸

pH

The premixed solution has a pH from 5.7 to 6.4.³⁸⁹⁸

Trade Name(s)

Pepcid

Famotidine is administered by intravenous injection or infusion.³⁸⁹⁷ For injection, 2 mL of the concentrate (20 mg) should be diluted to 5 to 10 mL with sodium chloride 0.9% or other compatible solution and injected over at least 2 minutes.³⁸⁹⁷ For intravenous infusion, 2 mL of the concentrate (20 mg) should be diluted in 100 mL of dextrose 5% or another compatible solution and infused over 15 to 30 minutes.³⁸⁹⁷

The premixed infusion solution is administered by intravenous infusion over 15 to 30 minutes.³⁸⁹⁸

Intact vials of the concentrate should be stored at 2 to 8°C.³⁸⁹⁷ If freezing occurs, thaw at room temperature and allow time for all components to resolubilize.³⁸⁹⁷

Although refrigeration is recommended, the manufacturer has indicated that the drug may be stored at room temperature for 26 weeks¹²³⁹ and for 3 months²⁷⁴⁵ at controlled room temperature in differing statements.

Diluted solutions of famotidine in most commonly used infusion solutions (e.g., sodium chloride 0.9%; dextrose 5%; dextrose 10%; Ringer’s injection, lactated; sterile water for injection) are stated to be stable for 7 days at room temperature; however the manufacturer recommends diluted solutions be refrigerated and used within 48 hours.³⁸⁹⁷

Famotidine premixed infusion solution should be stored at controlled room temperature (25°C) and protected from excessive heat.³⁸⁹⁸ Brief exposure to temperatures up to 35°C does not adversely affect the stability of the product.³⁸⁹⁸

Freezing Solutions

Famotidine (MSD) 200 mcg/mL in dextrose 5% or sodium chloride 0.9% in polyvinyl chloride (PVC) bags showed no loss when frozen at -20°C for 28 days followed by storage at 4°C for 14 days.¹²⁷¹

Famotidine (MSD) 2 mg/mL in dextrose 5%, sodium chloride 0.9%, or sterile water for injection stored in polypropylene syringes (Becton Dickinson) exhibited a 5 to 8% loss in 8 weeks when frozen at -20°C.¹⁴⁸⁶

Syringes

Famotidine (MSD) 2 mg/mL in dextrose 5%, sodium chloride 0.9%, or sterile water for injection stored in plastic syringes (Becton Dickinson) exhibited no loss in 14 days at 4°C.¹⁴⁸⁷

Central Venous Catheter

Famotidine (Merck) 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

Solution Compatibility

Additive Compatibility

Y-Site Injection Compatibility (1:1 Mixture)

For a list of references cited in the text of this monograph, search the monograph titled References.

ASHP^® Injectable Drug Information^TM. Selected Revisions December 5, 2024. © Copyright, 2024. American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.