This is a judgemental call. The methamphetamine act to keep a person awake. The anesthesia puts a person to sleep, and as a side effect depresses the respirations. If you are on methamphetamines, and anesthesia, if the stimulant wears off you may be under too much sedative. In any event, it complicates the calculation of the correct doseage. Too much of certain sedatives will cause diminishing of surgical "landmarks", so the idea is to use as little as necessary.
Is the methamphetamine for recreational use? Because then honestly, the length of time to "abstain" would be forever. I use a medication (prescription) for narcolepsy and they are letting me take it right up to the morning of my upcoming surgery. Surgery involves more than just the anesthesia. There is the pain management afterward and there are issues involved if someone is addicted to something like methamphetamine. It's like smoking. I have to stop smoking the day before my surgery. I can wear the patch, but they don't want me to actually smoke because it's too hard on my lungs with getting the anesthesia. I can't give you a time frame, but if your friends methamphetamine use is for recreation, the best is advice is to stop completely, forever. That stuff is just bad news.
i am due to have surgery in seven days i used a small amount of methamphetamine is it still safe ro have an anaesthectic
What do you take for narcolepsy? Isn't that a stimulant? I don't think you are one to give advice about meth if you are on meds for NARCOLEPSY.