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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 7 of 7. This is the beginning of the thread.
Posted by don_bristol on July 28, 2004, at 6:56:41
How late in the day are you people taking Parnate?
The Patient Information Leaflet which come with my Parnate here in the UK says to take the second (last) dose at 3 p.m.
To me 3 p.m. seems early. In order to spread the dose out, I try and take my Parnate as late as possible because I read that Parnate's half-life is short at 1.5 to 3 hours.
Don
Posted by King Vultan on July 28, 2004, at 7:45:40
In reply to How late in afternoon should I take Parnate?, posted by don_bristol on July 28, 2004, at 6:56:41
> How late in the day are you people taking Parnate?
>
> The Patient Information Leaflet which come with my Parnate here in the UK says to take the second (last) dose at 3 p.m.
>
> To me 3 p.m. seems early. In order to spread the dose out, I try and take my Parnate as late as possible because I read that Parnate's half-life is short at 1.5 to 3 hours.
>
> DonIt's the MAO inhibition that is more important than the actual half life. That is, the major effect of the drug is to inhibit monoamine oxidase, a molecule of which is permanently rendered useless once the Parnate bonds to it. That effect will continue long after the 1.5 to 3 hour half life.
I think it's wise to spread the dosages out as much as possible for maximum MAO inhibition efficiency, as well as to spread out the stimulatory effects of this drug and avoid the possibility of a spontaneous hypertensive crisis. As for when the last dose should be taken, I would not take it so late that it screws up your sleep. My plan for when I am on 3 x 10 of this probably in early September will be to take 1 pill each at 6 AM, Noon, and 5 PM, but I can always modify this a little if necessary.
Todd
Posted by don_bristol on July 29, 2004, at 6:02:21
In reply to Re: How late in afternoon should I take Parnate?, posted by King Vultan on July 28, 2004, at 7:45:40
King Vultan (Todd) wrote:
>> It's the MAO inhibition that is more important than the actual half life. That is, the major effect of the drug is to inhibit monoamine oxidase, a molecule of which is permanently rendered useless once the Parnate bonds to it. That effect will continue long after the 1.5 to 3 hour half life. <<
Todd, you make a good point that it is the MAO inhibition that is more important than the actual half life of the compound.
Do you know how long this MAOI inhibitory effect lasts for after a dose of an MAOI like Parnate?
It can't last all that long because all the recommendations I have seen for Parnate include a second dose each day.
Often the recommended timing of this second dose is only a five or six hours after the first one. So I guess that those few hours could be significant.
Posted by King Vultan on July 29, 2004, at 7:51:18
In reply to How long does MAOI inhibition last with each dose? » King Vultan, posted by don_bristol on July 29, 2004, at 6:02:21
Well, the MAO molecule that the MAO inhibitor binds to is permanently rendered useless (in the case of both Nardil and Parnate, which are irreversible MAOIs). However, the body is constantly making new MAO, so what you have is some type of equilibrium forming between the MAO and MAOI. The two main parameters controlling it would be the dosage of the MAOI versus the rate at which the body produces new MAO. Together, these factors govern the degree to which a person's total MAO is inhibited.
Todd
Posted by don_bristol on August 2, 2004, at 14:45:42
In reply to Re: How long does MAOI inhibition last with each dose? » don_bristol, posted by King Vultan on July 29, 2004, at 7:51:18
>> Well, the MAO molecule that the MAO inhibitor binds to is permanently rendered useless (in the case of both Nardil and Parnate, which are irreversible MAOIs). However, the body is constantly making new MAO, so what you have is some type of equilibrium forming between the MAO and MAOI. The two main parameters controlling it would be the dosage of the MAOI versus the rate at which the body produces new MAO. Together, these factors govern the degree to which a person's total MAO is inhibited.
>
> Todd <<=======
Todd, if the mechanism is how you describe it (and I am perfectky happy to believe what you write) then why is it worth anyone bothering to take their Parnate as two or three doses a mere few hours apart?
Id the MAOI destroying effect is occuring then I can't see how a few hours makes much difference.
Posted by King Vultan on August 2, 2004, at 20:24:36
In reply to Re: How long does MAOI inhibition last with each dose? » King Vultan, posted by don_bristol on August 2, 2004, at 14:45:42
>
> =======
>
> Todd, if the mechanism is how you describe it (and I am perfectky happy to believe what you write) then why is it worth anyone bothering to take their Parnate as two or three doses a mere few hours apart?
>
> Id the MAOI destroying effect is occuring then I can't see how a few hours makes much difference.
The body is producing new MAO all the time, so if, for example, you take a dose at 8 AM and one at 4 PM, the second dose has the opportunity to destroy some of the new MAO that has been created in the intervening time. Parnate's half life is so short (as is Nardil's) that very little of the first dose would be left by the time you take the second one. So by splitting the dosage, you do increase the efficiency of the MAOI. How much? I have no idea, but somebody's probably done a study on it at some point in time.With Nardil, where the timing of the dosage does not seem directly related to insomnia as it can with Parnate, you can spread the dose evenly throughout the day, even taking a pill at bedtime to destroy some of the new MAO that has been created since the evening dose. I suppose it is extra work to split the dosage on these MAOIs, but since I have a pill container with nefedipine (for a hypertensive crisis) and ibuprofen (for regular headaches), it's not a big deal for me to throw in there the MAOI pills that I will be needing during the day.
With Parnate--as opposed to Nardil--there are a couple of other reasons to split the dosage. One is to spread the stimulatory effect out somewhat, and the other is to lessen the chance of a spontaneous hypertensive crisis, that is, a hypertensive reaction that occurs without ingesting any of the prohibited foods or drugs. For the last reason alone, I would recommend splitting the dosage, as safety should always be a high priority.
Todd
Posted by don_bristol on August 3, 2004, at 7:24:38
In reply to Re: How long does MAOI inhibition last with each dose? » don_bristol, posted by King Vultan on August 2, 2004, at 20:24:36
QUOTE >> The body is producing new MAO all the time, so if, for example, you take a dose at 8 AM and one at 4 PM, the second dose has the opportunity to destroy some of the new MAO that has been created in the intervening time. Parnate's half life is so short (as is Nardil's) that very little of the first dose would be left by the time you take the second one. So by splitting the dosage, you do increase the efficiency of the MAOI. How much? I have no idea, but somebody's probably done a study on it at some point in time.
With Nardil, where the timing of the dosage does not seem directly related to insomnia as it can with Parnate, you can spread the dose evenly throughout the day, even taking a pill at bedtime to destroy some of the new MAO that has been created since the evening dose. I suppose it is extra work to split the dosage on these MAOIs, but since I have a pill container with nefedipine (for a hypertensive crisis) and ibuprofen (for regular headaches), it's not a big deal for me to throw in there the MAOI pills that I will be needing during the day.
With Parnate--as opposed to Nardil--there are a couple of other reasons to split the dosage. One is to spread the stimulatory effect out somewhat, and the other is to lessen the chance of a spontaneous hypertensive crisis, that is, a hypertensive reaction that occurs without ingesting any of the prohibited foods or drugs. For the last reason alone, I would recommend splitting the dosage, as safety should always be a high priority. << UNQUOTE
=======
Todd, thank you for a useful explanation.
I guess that we could extend the princile of splitting the dose for reasons of efficacy to taking a half-pill of Parnate several times a day to knock down the MAJORITY of the monoamine oxidase in the body.
I am guess here that like so many things if life that the amount of MAO knocked out by a full tablet of Parnate is less than double the amount of MAO knocked out by half a tablet of Parnate. (If you see what I mean.)
Sort of like the 80:20 rule of thumb where 20% of the effort produces 80% of the total results and the remaining results need a lot more effort.
Don
This is the end of the thread.
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