Pharmacology Update

IV Pantoprazole—The First Parenteral PPI

By William T. Elliott, MD, FACP, and James Chan PharmD, PhD

The first parenteral proton pump inhibitor (PPI) is now available in this country. Wyeth Laboratories’ pantoprazole, which has been marketed for more than a year under the trade name Protonix, will soon be available as an injectable for use in hospitals. Although this is the first PPI available in a parenteral form in this country, several others are currently available in Europe.

Indications

Pantoprazole sodium IV is indicated for short-term treatment (7-10 days) of gastroesophageal reflux disease (GERD) in patients in whom oral therapy is not appropriate.1

Dosage

The recommended dose of pantoprazole sodium is 40 mg daily for 7-10 days. It should be administered over a period of 15 minutes at a rate not faster than 3 mg/min. No dosage adjustment is required in patients with mild, moderate, or severe renal impairment, or mild or moderate hepatic impairment.1 Pantoprazole sodium is supplied as a freeze dried powder containing 40 mg of pantoprazole.

Potential Advantages

Pantoprazole is the first PPI to be available in parenteral form. The oral and intravenous forms of pantoprazole appeared to be equipotent. No change in dosage is required when switching from one formulation to the other.2,3 Pantoprazole has low potential for drug-drug interactions involving the cytochrome P450 isoenzymes.1

Potential Disadvantages

Postmarket spontaneous reported adverse events involving intravenous or oral pantoprazole have included anaphylaxis, angioedema, anterior ischemic optic neuropathy, severe dematologic reactions (eg, erythemia multiforme, Steven-Johnson syndrome, toxic epidermal necrosis, and hepatocellular damage).1

Comments

Pantoprazole sodium is the first PPI to be available in an injectable form. For patients temporarily unable to take oral PPI initiating therapy with parenteral pantoprazole for 5-7 days followed by oral pantoprazole for 8 weeks has been shown to be effective in the healing of moderate or severe (stage II and stage III) GERD.4 Complete healing was achieved in 77% of patients in 4 weeks and 85% in 8 weeks based on intent-to-treat analysis and 87% and 95%, respectively, per protocol. Parenteral pantoprazole (160-240 mg/d) has also been reported to be effective in controlling acid output in patients with Zollinger-Ellison syndrome.5 Pantoprazole costs about $24 per 40 mg vial.

Clinical Implications

Pantoprazole sodium is the first parenteral PPI approved in the United States. Only histamine 2 receptor antagonists such as ranitidine, famotidine, and cimetidine are currently available in parenteral form. When a PPI has been needed in patients unable to swallow the oral dosage form, the drug has been administered by mixing it with a liquid and injecting it through the nasogastric tube. The parenteral form would facilitate administration in this setting. Although the drug is only approved for GERD, other potential uses of parenteral PPIs include Zollinger-Ellison syndrome, prevention of stress ulcer, acid-induced lung injury, and bleeding peptic ulcers.6

References

1. Protonix IV Product Information. Wyeth Laboratories. May 2001.

2. Pisegna JR. J Clin Gastroenterol. 2001;32(1):27-32.

3. Hartmann M, et al. Aliment Pharmacol Ther. 1998; 12(10):1027-1032.

4. Wurzer H, et al. Hepatogastroenterology. 1999;46(27): 1809-1815.

5. Lew EA, et al. Gastroenterology. 2000;118(4):696-704.

6. Metz DC. Digestion. 2000;62(2-3):73-81.