MAO Inhibitors and meperidine,

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MAO Inhibitors and meperidine,

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DrPak
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01/16/06 - 01:38 AM

How does MAO inhibitor + meperidine cause a HTNive crisis? I can understand tyramine and MAO causing such a crisis because tyramine increases NE activity and MAO may potentiate that to the point of a crisis. But how does meperidine do it?

sarika
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01/16/06 - 03:01 AM

meperidine blocks M receptors leading to vasoconstriction in vessels. Maybe that has something to do with it..i am not sure though its just what came to my mind!

dariush
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01/16/06 - 03:24 AM

yeah i cam across this Q in Kalplan Qbook also. it does not explain clearly how. does anybody know a concrete explaination?

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mjl1717
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01/16/06 - 06:24 AM

Probably an idiosyncratic reaction. Not in Goodman and Gillman.

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DrPak
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01/16/06 - 07:17 AM

wow... thanks for checking Goodman & Gillman. There doesn't seem to be any concept then, just donkey-memorization! I guess it's worth knowing if it came in the Qbank and is present in FA.

mjl1717
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01/16/06 - 07:55 AM

It also mentioned that multiple types of reactions could be seen such as: severe respiratory depression or excitation, delirium or hperpyrexia, convulsions. Also stating that similar interactions with MAO inhibitors were NOT seen with other opiods. What gets me is that I was under the impression that meperidine was the opiate someone would take if they did NOT want the pupillary constrition, but Goodman and Gillman contradicts this. Anyone have any info on this. "Donkey memorization" is a good play on words. wink

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DrPak
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01/16/06 - 08:13 AM

Actually, that might be it. Meperidine has M-blocking action, and MAOI have adrenergic action. The two put together sort of gives you a sympathomimetic action, and if you stretch that a little further, a HTNive crisis is not unimaginable.

It's a rough sort of concept, though.

infliximab
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01/16/06 - 12:13 PM

hi all

i did the kaplan life lecture last year, it was said that there are 2 opiates with SSRI activity, they are :

MEPERIDINE which forms normeperidine with SSRI activity &

DEXTROMETHOPHAN

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drk1980
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01/16/06 - 12:18 PM

well tht shd settle tht!

also anthr weird one...procarbazine (HD drug) has MAOI activity..

infliximab
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01/16/06 - 12:27 PM

#10

YES, SO I LEARNT, FROM THE FORUM OF RECENT

DrPak
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01/16/06 - 12:27 PM

#11

Ah! There it is, that's the explaination!

It seems a little digging bring outs a nice logical answer to all problems. It also explain why hyperthermia and seizures occurs with dextromethorphan.

tolito
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02/22/06 - 03:07 AM

#12

hi mj17171
meperidine has atropine like action so it dilates the pupils. you are right, unlike the opioids that constricts, it dilates.(cf lippincot)

i cannot find hypertensive crisis as an adverse drug intereaction when meperidine is combined with MAOI. What i find is HYPERPYRETIC coma. meperidine (or pethidine) causes HYPOTENSION.

can someone clarify this? thanks.

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