I once had a pharmacology professor who told us, "Today's side effects are tomorrow's therapy." What he meant was one's garbage is another's treasure. Side effects in one setting can be used for therapeutic benefit in another.

A perfect example is minoxidil, the antihypertensive vasodilator, that had the unusual side effect of causing inappropriate hair growth. But when formulated in a cream whose distribution could be restricted by where you put it, voila!...you have Rogaine (Regaine outside the US).

Well, a similar situation has been emerging over the last several years with "cosmeceuticals" meant to increase the appearance of eyelashes. Several brands are available but the most visibly promoted is RevitaLash, developed by a California ophthamologist who, as the story goes, wanted to help his wife who had lost her eyelashes to cancer chemotherapy.

The background on this "breakthrough" relates to the side effect profile of prostamides, drugs that treat glaucoma by reducing intraocular pressure. These compounds mimic the effect of prostaglandin PGF2α to promote outflow of aqueous humor from the eye through the trabecular meshwork by acting as a local hypotensive. In the US, there are two such drugs: bimatoprost (Lumigan®) and latanoprost (Xalatan®).

Where am I going with this? Well, deep within the prescribing information for Lumigan (PDF here) one finds:

Lumigan® may gradually change eyelashes and vellus hair in the treated eye; these changes include increased length, thickness, and number of lashes. Eyelash changes are usually reversible upon discontinuation of treatment.

Hmmm...a side effect. Might this be used for cosmetic purposes?

Enter RevitaLash®. The chemical formula of the active component in RevitaLash® appears to be 7-(3,5-dihydroxy-2-(3-hydroxy-4-(3-(trifluoromethyl)phenoxy)-1-butenyl)cyclopentyl)-
N-ethyl-(1R-(alpha(Z),2beta(1E,3R*),3alpha,5alpha))-5-heptenamide. I could use Molecule of the Day to help me with the structure, but let it suffice to say that this compound is quite similar to bimatoprost (the 3-(trifluoromethyl)phenoxy appears to be the biggest difference). So, this analog is probably acting similarly to the prostamides but is likely not covered in the patents by either drug company marketing prescription versions of their glaucoma drugs.

According to the RevitaLash® website, this is what the product does:

Like liquid eyeliner, RevitaLash® is simply applied once a day. Within three to ten weeks, your own natural eyelashes will look Longer, Thicker, Fuller, and BEAUTIFUL!

With that said, the question has arisen recently that this statement may constitute a claim that might be made for a drug.

But from their legal notices page, one finds:

Revitalash® Eye Conditioner is not intended to stop, prevent, cure, treat, relieve, alter, reverse or reduce eyelash loss or to promote the growth of eyelashes.

Well, that about covers it, huh? Totally clear, right? The disclaimer states the exact opposite of the claims made for the product on another page of the same website.

This leaves one to wonder: is the product intended to promote eyelash growth or not? It seems that the company wishes to have it both ways, perhaps to be as amorphous as possible to avoid any regulatory wranglings.

By the way, the product costs $149.95, plus shipping and handling.

At that price, you'd think they might be able to comp the shipping and handling.