Posted by Halina Harding on November 24, 2015, at 13:31:00
In reply to Emsam and narcolepsy, posted by back_to_school on August 12, 2013, at 23:31:17
Emsam slows the functioning of succinic acid dehydronase enzyme. For each 1mg of Emsam (selegiline), divide and reduce the dose of Xyrem (sodium oxybate) by the equivalent amount.
For example, common doses of the two medications administered independently are as follows:
Emsam: 6mg/qd
Xyrem: 4.5g/bid qhsWhen administered concomitantly:
Emsam: 6mg/qd
Xyrem: 0.75g/bid qhs reduce the Xyrem dose by 6 (or 9 or 12, depending on the dose of Emsam)Keep in mind that Xyrem suppresses dopamine and allows it to build up, then releases it when the drug wears off. Selegiline quadruples the number of dopamine receptors in the brain, allowing more dopamine to be produced and stored up.
Therefore, you will end up with far too much dopamine if doses ordinarily administered of Xyrem are given in combination with selegiline, particularly with Emsam which is not MAO-selective and affects MAO-A (but only in the brain). However, Selegiline also has a unique mechanism that detects the calcium channel and sodium channel cascade and may in fact completely block Xyrem at doses higher than approximately 2.25g.
Tolerance over time if a dose over 2.25g is given over a period of several weeks and can increase the neurotoxicity of Xyrem. It should not occur at lower doses. Keep in mind that these are starting dose guidelines and Xyrem can safely go up (but only if necessary, titrate to effect). Dont raise the dose until the pt has been taking the combo for several months/years.
Higher doses of Xyrem, however, will eventually override selegilines neuroprotective mechanism, while the accumulating succinic acid in the brain which will block the GABA-B receptor agonism at lower doses, resulting in oxidative stress, overstimulation, and withdrawal symptoms.
The manufacturers of both medications report no interaction between the two drugs, but not all drug interactions are common or classified as such. Therefore, please exercise caution and work with your prescriber to come up with the best treatment plan.
Some notes on Xyrem:
- temperature sensitive and lower temperatures will degrade the medicine (must be 68F-77F)
- if the medicine degrades due to temperature, it will dissolve the plastic bottle its stored in, the dosing syringe, and dosing cups. it will also dissolve your teeth, if it degrades and is then not subsequently diluted with water (see below).
- adding water to the medicine will cause it to spoil and particularly to fungal contamination
- absorbed through aerobic metabolism, the medicine is not absorbed like food, it goes into the air you breathe by coming up through from the stomach through the esophagus and is inhaled into the lungs
- food and water in the stomach will dilute and/or spoil the medication and prevent from being effective
- taste: salty/sweet (stabilized sodium oxybate) or no salty taste (degraded into 25-50% butyrolactone); eventually degraded medicine will develop an off taste from the pH change causing fungal spoilage
- raising the temperature of the medicine will stabilize the medication (could take up to a week at room temperature)
- oral dosing syringes will turn white and hazy when the medication is dissolving the plastic; also the rubber stopper will stick; at this point discard the syringe as it cannot be reversed
- add a small amount of air to the top of the oral syringe before measuring the ensure that the medication does not touch the rubber stopper
- baxter piba (clear and soft rubbery plastic) tends to burp the medicine and causing small air bubbles and droplets vs comar (white and firm/hard plastic) which will measure up smoothly
- refrigeration will cause the medicine to degrade and/or dissolve the bottle
- never ever drink cold or refrigerated Xyrem - particularly without dilution!FYI, there is a patent on using Selegiline as a neuroprotective mechanism and over the treatment of overdose with Sodium Oxybate.
Dr Harding
poster:Halina Harding
thread:1048892
URL: http://www.dr-bob.org/babble/20151119/msgs/1084186.html