Gralise and horizant

Hi. This is Richard Mullvain, and I'd like to welcome you to our Essentia Health Med Moment video, a service brought to you by Essentia Health pharmacists. Hi. My name is Stephanie Grube. I'm a pharmacy practice resident at Essentia Health-St. Mary's Medical Center in Duluth. I'm here today to talk to you a little bit about two new formulations of an old drug, two extended-release gabapentin agents. The first one I'm going to talk about is called Gralise. It is in the same drug molecule as Neurontin; however, it is in an extended-release formulation, so for this reason it is not interchangeable with other forms of gabapentin. A little bit about this drug – it's approved for postherpetic neuralgia, and it's a once-a-day formulation, so you take it in the evening. You have to titrate the dose similar to Neurontin; however, you do reach your maximum dose on day 15, which is a little bit shorter than regular gabapentin. A little bit about the kinetics: Gralise, the 1,800 mg daily, and the gabapentin immediate release, 600 mg three times a day – they have a similar drug exposure; however, the time to the Tmax, the max concentration, is 3 hours for Gralise, where it is only 2 hours for gabapentin, and you also get less fluctuations in your plasma levels. The other drug that was approved, Horizant, is a gabapentin enacarbil pro-drug of gabapentin, and it is also an extended-release once-a-day formulation. It is approved for primary restless leg syndrome, and this is an indication that regular Neurontin does not have, so this is a new indication for the Horizant. This is a once daily low-dose, 600 mg with food. Similar to the Gralise, the pharmacokinetics – it has a Tmax of 7.3 hours, so pretty close to the Gralise agent as well. How these agents work: Gabapentin is structurally related to GABA neurotransmitter, but we do not know how it exerts its effects. Some contraindications and precautions with this drug: Similar to gabapentin, abrupt discontinuation can precipitate seizures, so it's important to titrate patients off of this medication. Since they are extended-release agents, they must be swallowed whole, and they should be taken with an evening meal to increase the bioavailability and absorption. Also, like Neurontin, they are cleared renally, so renal dose adjustments are needed, and they should not be used in patients with a creatinine clearance less than 30. Common side effects of these agents: Dizziness and somnolence are the two main ones, and then there are also diarrhea, dyspepsia, possible mood changes and peripheral edema, although these are more rare. In summary, Gralise is a single daily dose, probably more convenient for patients and possibly with increased compliance for postherpetic neuralgia over the three times daily gabapentin. Horizant is a new option for the treatment of restless leg syndrome. However, both of these are new brand names so they will be more expensive than gabapentin. Thank you. Thanks for watching this Essentia Health Med Moment video, a service brought to you be Essentia Health pharmacists.

Source: http://dailydose.essentiahealth.org/uploads/graliseandhorizant.pdf