December 28th, 2009

Holiday Surprise: Generic Valacyclovir

Last week one of my patients went to refill a Valtrex prescription, and was offered generic valacyclovir for the first time.  It made him nervous, so he requested I write a “brand-name only” script.

I confess the existence of a generic formulation of valacyclovir — which according to the PharmD here has been available for several months — was news to me. presents(Generic acylcovir and famciclovir* have been available for years.)

And while there is no reason to suspect generic valacylcovir will have any unusual issues related to efficacy or toxicity compared to the branded version, this Times article reminds us that this is not always the case:

Joe Graedon, who has been writing about pharmaceuticals for three decades and runs a consumer advocacy Web site, the People’s Pharmacy (, was 100 percent behind generics for many years.  “We were the country’s leading generic enthusiasts,” he told me recently. But over the last eight or nine years, Mr. Graedon began hearing about “misadventures” from people who read his syndicated newspaper column.

What follows are some anecdotal experiences and opinions — largely from the psych, neurology, and cardiology fields — about the potential dangers of even slight differences in bioequivalence or excipients between branded and generic drugs.  For even more of the same, read the comments section here.

Which brings me back to my patient:  Since he’s taking the Valtrex for an unusual reason (recurrent HSV-related meningitis), and since he’s willing to pay extra for the branded version, I went ahead and wrote the “brand name only” script.

My thinking?  Let’s see what a year or so of experience with generic valacyclovir brings us when used for more typical indications before making the switch.

(*Why isn’t this spelled “famcyclovir”?)

5 Responses to “Holiday Surprise: Generic Valacyclovir”

  1. shelby says:

    I am curious to hear others’ experiences on this.

    My insurance company’s mail order pharmacy recently substituted generic valacyclovir in lieu of Valtrex. I was thrilled to see the 75% plus savings. However, in the past month and a half, I have had more outbreaks than I have had altogether in the past ten years that i have been taking Valtrex (500 mg daily) as maintenance therapy for genital herpes. This is happening even after i doubled my dose of the generaic. There may be other factors at play – but I am not taking any chances and have asked my doctor to prescribe “medically necessary”.

    • Paul Sax says:

      Shelby, this is just the sort of “n=1” experience that is invaluable after licensing of a new drug, generic or otherwise. It would be great if there were an easy way to aggregate such reports — not sure there is one yet.

  2. Mike says:

    I also switched to the new generic valacylovir approximately 2 months ago and have had two HSV2 outbreaks since then. This is in contrast to the 5 months previous to this when I took Valtrex daily at the same dose (1g/day) and I had no outbreaks at all. Fortunately my doctor is willing to provide me with another precription for Valtrex “no generic substitute.”

  3. Cameron says:

    I have had HSV2 for 20+ years and after discovering that I had elevated liver enzymes and a minor ‘fatty liver’, stopped taking generic Acyclivor about 2 years ago.. I have had multiple outbreaks since (both acute and almost consant shedding)but my liver enzymes have dropped back into the very low range.
    My delima now is do I constantly live with asymptomatic shedding and more frequent outbreaks, or do I jump back in and go with a branded valacylovir and take the risk of damaging my liver ??
    Any thoughts ??

  4. Paul Sax says:

    Cameron, as your doctors no doubt told you, fatty liver has many many causes — including some medications. If you choose to go back on chronic suppressive therapy, would do so only with periodic liver test monitoring.


HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

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NEJM Journal Watch
Infectious Diseases

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