Posted by ed_uk on March 19, 2005, at 14:24:13
In reply to Re: Analgesics » ed_uk, posted by cubbybear on March 19, 2005, at 7:34:32
Hi Cubbybear!
>I also have had major concerns about going for a routine colonoscopy. If the dr. says that it could be done with local anaesthesia and a sedative, I will certainly go that route, rather than with major anaesthesia.
Standard practice in the UK is to give an IV sedative, usually midazolam (Hypnovel, Versed) and an opioid, often pethidine (meperidine, Demerol). You must *not* let them give you any pethidine/meperidine!!!
IV midazolam or on its own would probably provide adequate sedation, it might cause a drop in blood pressure if the dose was excessive. If midazolam causes an excessive drop in blood pressure, an antidote is available - flumazenil. Certain blood pressure elevating drugs such as ephedrine are not safe for patients taking MAOIs.
>local anaesthesia
Some gastro-enterologists use lidocaine (lignocaine, Xylocaine) ointment to numb the anus.
>major anaesthesia
General anesthesia isn't commonly used for colonoscopy. If the colonoscopy is first attempted under sedation but it fails due to pain, general anesthesia may be recommended. Also, if someone is too anxious to have the procedure while they are awake, general anesthesia may be used.
For pain relief during colonoscopy, opioids are commonly given. Pethidine/meperidine is one of the most dangerous opioids for patients taking an MAOI, this is because the combination can cause the serotonin syndrome - this is because pethidine/meperidine acts as a serotonin reuptake inhibitor, a bit like an SSRI!
Other opioids which you should avoid include... tramadol, propoxyphene (dextropropoxyphene) and pentazocine. Low doses are morphine generally seem to be ok although some patients have become oversedated and required the opioid antidote naloxone (Narcan).
Since the data on the interaction between *other* opioids and Parnate is limited, it would probably be safest to perform the procedure using IV midazolam *alone*. If an opioid was necessary, morphine would probably be ok but the interaction has not been well studied.
From dr bob's tips...
'Having observed severe hypertension when an elderly patient of mine on Parnate (tranylcypromine) recieved codeine, I now warn all my patients on MAOIs to avoid all narcotic analgesics.'
This is the only report of an interaction between codeine and an MAOI that I've ever seen!
If the procedure is too uncomfortable and you need more sedation, propofol is sometimes used to induce deep sedation - this sedation is normally performed by an anesthetist. Propofol is a powerful IV sleep-inducing drug. As far as I know, there are no reports of propofol interacting with MAOIs. Low blood pressure might occur.
What is your BP at the moment? Do you get dizzy when you stand up?
If you need general anesthesia for your shoulder, if might be useful to give the anesthetist a reliable list of drug interactions, your pdoc could help you produce this. You could stick it on your drug chart!!
Opioid anesthesia (anesthesia based on a very high dose of an opioid such as fentanyl) might not be suitable, one patient taking an MAOI died after receiving opioid anesthesia. The symptoms resembled serotonin syndrome, fentanyl is related to pethidine/meperidine, it is possible that fentanyl may be weakly serotonergic. The death may have occured due to the very high dose given, low doses are probably ok - again, the interaction has not been well studied.
Most general anesthesia involves the administration of lower doses of opioids, the opioid dose can be minimised by giving higher doses of sedative-hypnotics such as propofol or anesthetic gases such as isoflurane. This type of anesthesia may be safer for you. Low blood pressure may be a problem, the anesthetist must be well informed about which blood pressure elevating drugs ('pressors', sympathomimetics) can be safely combined with MAOIs and which need to be avoided.
The following 'pressors' can usually be combined safely with MAOIs if it is important to elevate the patient's blood pressure. Traditional textbooks will often tell you that these drugs must be avoided, it is true that the blood pressure elevation produced by these drugs may be greater in patients taking MAOIs compared with patients not taking MAOIs. Low doses must be given initially, the dose must be carefully titrated/individualised...........
epinephrine/adrenaline
norepinephrine/noradrenaline
methoxamineThe folowing 'pressors' should generally be avoided in patients taking MAOIs, the response may be unpredictable and severe hypertension may result........
ephedrine
metaraminol.......The are many other 'pressors' which also interact serious with MAOIs, I won't list them here because I don't know which ones are used by anesthetists in Thailand. I can send you some more info if you need surgery.
>I JUST got this brilliant idea--that if surgery were necessary, I would enlist the assistance of my psychiatrist (who obviously knows all about MAOIs) and put him in touch with the gastroenterologist (for colonoscopy) or orthopedist (for shoulder). There *are* many doctors who are familiar with MAOIs here; the more important issue, i guess, is whether the anaesthetists are knowledgeable and willing to work with an MAOI patient.
Yes, this is a good idea. You definitely need to get in contact with the people who'll be treating you in advance.
>Are you serious? Opioids might not be effective in my case? So what alternatives could there possibly be, that would also be compatible with Parnate?
A higher dose of Voltaren or another NSAID might be more effective than an opioid. Have you tried taking aspirin 900mg four times a day?
*Do not combine aspirin with diclofenac*
Aspirin and diclofenac are both capable of causing peptic ulcers, if they are combined the risk is dramatically increased.>Truthfully, I'm scared of the gastro-intestinal risks, although I'm in the low-risk category for NSAIDs.
You could ask your doctor about using a gastro-protectant such as lansoprazole.
>>Have you asked your doctor whether it is safe to take a higher dose?
>Yes, but he said that in my case, I'd best cut it out after a max. of 2 months.You never taken a full dose yet so you've got plenty of time :-)
>Never heard of Paracetamol until I came to Thailand.
Where are you from? Paracetamol is called acetaminophen (Tylenol etc) in some countries.
>Would a combo of Diclofenac and aspirin be as effective, do you think? (come to think of it, I've already tried diclofenac w/aspirin at low doses/as needed and saw no improvement)
Combining aspirin with diclofenac is dangerous, it is toxic to the stomach! Taking a higher dose of diclofenac on its own would be safer. Diclofenac can be combined with acetominophen, but not aspirin or other NSAIDs.
>Can't believe it! After all the posts and info I've been reading, to learn this is quite a surprise.
An opioid might be helpful, I'm not saying it wouldn't be. Opioids are not generally first-line for your type of pain though, because other drugs are often more effective. A combination product such as Percocet might be prescribed if paracetamol, diclofenac and muscle relaxants weren't helpful. Percocet is often very constipating, prepare to purchase some laxatives!
>It's made in Japan. Don't know why the distribution is seemingly limited.
Interestingly, a lot of Japanese psych drugs are only marketed in Japan! Many of them are virtually unknown to the West.
Perhaps you could try an increased dose of Myonal if you're still in pain in a few weeks time. I don't know much about Myonal, can't give any info.
RE the shoulder surgery.....
General anesthesia + MAOIs is 'traditionally' contra-indicated. Some anesthetists now believe that such anesthesia can be performed safely in experienced hands; this is what I posted to ace.
Anesthesia + Parnate is unlikely to be as safe as anesthesia w/o Parnate, you will have to weigh up the risks of d/cing the Parnate against the risks of continuing it. I honestly don't know how easy it will be for you to find an anesthetist who is willing to treat you while you're still taking Parnate. Best of luck :-)
Take care,
Ed.PS. An analgesic called nefopam is available in some countries, it *can't* be combined with Parnate though!!
poster:ed_uk
thread:470781
URL: http://www.dr-bob.org/babble/20050317/msgs/472848.html