AHFS Class:

12:16.04.04 Non-selective alpha-Adrenergic Blocking Agents

Generic Name

• Phentolamine Mesylate (CAS Registry Number: 65-28-1)

Phentolamine mesylate is available as a lyophilized powder in vials containing phentolamine mesylate 5 mg with mannitol 25 mg.¹⁹⁶⁵ Reconstitute vial with 1 mL of sterile water for injection.¹⁹⁶⁵

pH

4.5 to 6.5.⁴

Phentolamine mesylate may be administered by intramuscular or intravenous injection.¹⁹⁶⁵

Intact vials should be stored at controlled room temperature.¹⁹⁶⁵ Although the manufacturer recommends that reconstituted solutions be used immediately and not stored,¹⁹⁶⁵ other information indicates that such solutions are stable for 48 hours at room temperature and 1 week at 2 to 8°C.⁴

Sorption

Phentolamine mesylate was shown not to exhibit sorption to PVC bags and tubing, polyethylene tubing, Silastic tubing, and polypropylene syringes.⁵³⁶; ⁶⁰⁶

Additive Compatibility

Drugs in Syringe 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 September 12, 2024. © Copyright, 2025. American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.