Posted tagged ‘psychostimulants’

Methylphenidate revealed

February 4, 2014

The Pediatric Insider

© 2014 Roy Benaroch, MD

Warning: this isn’t really a general interest sort of post. It’s more for people who prescribe methylphenidate (commonly called Ritalin), and maybe parents whose kids take the stuff. It gets odd and picky and technical, but since I had to look at this stuff up to keep it straight in my mind, I figured someone else out there needed this kind of detail. Enjoy, or skip it!

What the heck is going on with methylphenidate (MPH)? Generic substitutions may not be what you expect. If you’re picky about the form and kinetics of what’s being prescribed, you have to pay attention.

Plain MPH is still easy. Tabs come as generic or “branded” as Ritalin or Methylin, in 5s, 10s (scored), and 20s (scored.)

When you get to the time release MPH, that’s when things get tricky. The oldest one used to be branded as Ritalin SR, and it’s still out there—20 mg of MPH in a wax-impregnated tablet, only at one dose (20 mg), with irregular breakdown and absorption. It falls apart when it wants to, and no two tabs are the same. A “generic”, of sorts, of Ritalin SR in a similar wax tablet came out as brand Metadate ER tabs (originally in 10s and 20s, now only in 20s.) You’ll see either marked as generic “methylphenidate ER tabs”—always in tablets, always 20 mg.

Metadate then extended their brand into capsules, marketing these as Metadate CD (available in 10, 20, 30, 40, 50, and 60 mg.) Rather than wadding up all of the MPH into one lump of wax, this line of capsules contains individual small beads of medicine, some of which are wax coated for delayed release. The Metadate CD line has 30% of the MPH uncoated (immediate release), and 70% coated for delayed release. Generics of these are called “methyphenidate ER capsules”—so beware, capsules and tabs are very different when you see methylphenidate ER. Caps = reliable sustained-release technology; tabs = blob of wax.

Ritalin LA brand is also a capsule of beads, though they use a 50:50 mix of immediate and delayed beads. If a patient on Metadate CD needs more of an AM “push”, switching to the same mg dose of Ritalin LA will provide more of an immediate action. Ritalin LA comes in 20, 30, and 40 mg capsules. Some pharmacies will substitute Ritalin LA, Metadate CD, and methylphenidate ER caps, even though they are NOT interchangeable because of the differing ratio of immediate to delayed beads in the caps. You want real 50:50 Ritalin LA? You’ve got to “Brand Necessary” the rx.

Concerta (or, at least, brand-name Concerta) uses a unique time-release delivery system for the MPH, called “OROS.” An undigestible shell surrounds a core of MPH, with a tiny sponge inside that slowly absorbs gut juice, expanding to push MPH out gradually through a tiny hole. Clever! And it really should provide even delivery. They also coat the outside of the shell with about 20% of the total MPH for an immediate effect (that’s less than Metadate CD’s 30% — Concerta is the time-release MPH that starts the slowest.) Concerta comes in weird doses: 18, 27, 36, and 54. There are now generics of Concerta, called methylphenidate ER (yes, the same name as other generic time-release methylphenidate), in the same weird milligram amounts. But only SOME of these generics use the OROS system. Others use some kind of wax matrix (that I suspect is as low-tech as old-school Ritalin SR.) The generic Concerta that doesn’t use OROS is still shaped like Concerta, making it difficult to spot, but the delivery is very different from real Concerta. If you want to ensure you’re getting the expected time-release technology, you have to either specify “Brand Necessary” Concerta, or write “only substitute generic with OROS delivery technology.”

Daytrana is still out there, plugging away. It’s a patch that delivers MPH very evenly over up to 9 hours (that’s what FDA says. It probably lasts longer, or could last longer if you leave it on.) Drug delivery starts about 1h after the patch is applied, and stops 2 hours after the patch is removed. It comes in 10, 15, 20, and 30 mg patches, all of which are pretty darn irritating to many patients.

Then, the newest stuff: Quillivant XR, a liquid time-release MPH that the manufacturer claims lasts 8-12 hours. The strength is 5 mg/mL, and it’s non-substitutable. There’s also a traditional, ordinary, generic MPH liquid at both 5mg/5mL and 10 mg/5mL.

For you single-isomer buffs, Focalin (dexmethylphenidate) comes in 2.5, 5, and 10s, and there’s a generic available (though according to Goodrx.com via Epocrates, the generic is actually a little more expensive.) Focalin XR, their bead-technology time-release form, comes in all multiples of 5 from 5 to 40 and has no generic form… yet*!

I think I’ve covered all of them, but welcome any comments, especially from pharmacists. The complexities of prescribing this one compound are just silly, and I’m sure this is leading to all kinds of misadventures. The FDA should step in and require more-transparent, easily understood labeling. Until they do, I’ll keep ya posted.

 

*edit: see the comments below– Focalin XR does have a generic, since Nov 2013.