Interesting stuff.
How much juice do you get out of the clonidine? The parallel for us is presumably dexmedetomidine, but while I know they say it's an analgesic, I've never found it to be all that potent for pain. Are hemodynamics limiting? Assume it's just one part of a larger puzzle, of course.
Have heard good things about the IV lidocaine thing but no experience. What is the interplay with its electrical effects? None of concern?
I don't have a lot of experience with demetetomidine because we don't have it where I work, hence the clonidine. People who use it regularly seem to love it. Others won't use it because they hate it. I don't have enough experience with it to have an opinion.
Clonidine seems to work pretty well, and the clonidine/ketamine/lidocaine combo is pure gold. When we give clonidine PO (0.2 or 0.3mg) it is common to hear about mild hypotension on the floor overnight, but it sounds like it typically resolves with a fluid bolus and they are getting more comfortable dealing with it. Have had no problems with being unable to discharge people because of hypotension. When you give an IV bolus you'll definitely see an effect on HR and MAP, but it usually isn't all that long lasting.
Lidocaine is an amazing drug. I've used ~2mg/kg boluses in combination with much-smaller-than normal doses of fentanyl to treat acute pain in large OSA patients who I didn't want to give dilaudid to, with excellent results. It seems to really potentiate the fentanyl, making it more potent and last longer, without the respiratory effects. A couple months ago I used the same dose plus some versed to completely terminate a migraine that had been refractory to everything the ED could think of (I had offered a SPG block but the patient was to anxious for that). During general cases, I typically give about 1-1.5 mg/kg on induction and then run an infusion at 2-3 mg/min, which works out to about 1-2 mg/kg/hr in most patients, and like I said, it works great. Haven't seen any problems with these larger doses of lidocaine at all. People do get a little loopy with much more than 1mg/kg bolus and I always instruct them to report any strange sensations or sounds as I'm giving it. Tinnitus or tongue or circumoral sensations is not uncommon. I think having benzos (and ideally, lipids) available is probably a really good practice, but lidocaine is pretty safe and forgiving. Just recently I read something somewhere about a place that was giving massive doses for chronic pain - I think it said they were working up to 10mg/kg for an hour over a handful of sessions!
Like I said before, I'm not sure how to translate this stuff outside the anesthesia setting. It just doesn't seem practical. Maybe in the ICU you could try a lidocaine infusion + low-dose ketamine infusion in patients whose pain is hard to manage, or in whom you want to minimize opioids for whatever reason? Even if it doesn't eliminate the need for narcs it might drastically reduce it. I've really started to be convinced that while narcs are certainly indispensable in many cases, prolonged dosing and large doses often causes as many problems as it solves. In someone who narcs just don't seem to be working in, you are likely seeing some sort of opioid-induced acute tolerance, if not an actual hyperalgesic state. No need to try to differentiate, really.
