Pharma: March 2009 Archives


March 4, 2009

The Supremes decided today that the fact that a drug is FDA approved doesn't pre-empt damages lawsuits for inadequate labelling. The most interesting part of this case for me, though is that Phenergan (promethazine) can cause "irreversible gangrene" is accidentally injected into an artery rather than a vein. Moreover, it's apparently somewhat tricky1 to administer correctly via an IV injection:

Due to the close proximity of arteries and veins in the areas most commonly used for intravenous injection, extreme care should be exercised to avoid perivascular extravasation or unintentional intra-arterial injection. Reports compatible with unintentional intra-arterial injection of PHENERGAN Injection, usually in conjunction with other drugs intended for intravenous use, suggest that pain, severe chemical irritation, severe spasm of distal vessels, and resultant gangrene requiring amputation are likely under such circumstances. Intravenous injection was intended in all the cases reported but perivascular extravasation or arterial placement of the needle is now suspect. There is no proven successful management of unintentional intra-arterial injection or perivascular extravasation after it occurs. Sympathetic block and heparinization have been employed during the acute management of unintentional intra-arterial injection, because of the results of animal experiments with other known arteriolar irritants. Aspiration of dark blood does not preclude intra-arterial needle placement, because blood is discolored upon contact with PHENERGAN Injection. Use of syringes with rigid plungers or of small-bore needles might obscure typical arterial backflow if this is relied upon alone.

I knew that some phenothiazines caused injection site irritation, but until recentl didn't know that promethazine was this bad. This seems like an excellent reason to avoid promethazine injections altogether, and if you must get them, have them done in your non-dominant hand.

1. Off-topic rant: why does Baxter think it's a good idea to password protect the PDF to prevent cutting and pasting? Further, why does Apple's PDF viewer—let along GMail's "view as HTML" feature—think it's a good idea to enforce this kind of caveman DRM? That said, Ghostscript seems to have your interests rather more at heart.