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        New Message Board Archives >> Medications, Treatments, Therapies 2003 >> The Imitrex "limit"
        
(Message started by: Unsolved on Nov 9^th, 2003, 7:30pm)

Title: The Imitrex "limit"
Post by Unsolved on Nov 9^th, 2003, 7:30pm

So, does anyone know how they came up with the 'limit' of 2 injections (12 mg) per a 24 hour period?

Has anyone ever heard of someone taking TOO much Tex and what did it do to them ?

I was just wondering because I use WAY MORE than the limit ALOT. Sometimes I require up to 8 shots a day at 4 mg a shot and it's never hurt me and it always takes away the pain.

Title: Re: The Imitrex "limit"
Post by Prense on Nov 9^th, 2003, 7:41pm

Good question UE...

I'd guess that GSK did testing to determine the safety of the med for FDA approval. Remember though...this med was initially approved for migraines. The brochure that comes with it even says that the safety of more than 4 per month has not been tested... That can be interpreted a number of ways. Your best source of information might actually come from a poison control center. I'm not sure.

Chris

Title: Re: The Imitrex "limit"
Post by pinksharkmark on Nov 9^th, 2003, 10:10pm

Prense is right. It's not that exceeding the recommended dosage is known to harmful, it's just that in order to get approval for the drug certain tests were run at certain dosage levels. Anything higher than those dosage levels is terra incognita from a legal liability point.

Someone here did post (maybe a year ago?) a report of clinical data from users like ourselves who routinely exceeded the recommended dose. No bad effects were found. Sorry I don't have a link to the post, but a search would probably turn it up.

Before I started using mushrooms to treat my CH, I used to exceed by at least double every 24 hours the maximum recommended dose -- for months at a stretch. My neurologist in Canada says many, MANY of his cluster patients do as well, and as yet neither he nor any colleagues of his have reported any negative effects (other than grossly deflated bank accounts, as in my case).

Of course, twenty years down the road some negative side effects may turn up. Who knows?

pinky

Title: Re: The Imitrex "limit"
Post by Ueli on Nov 10^th, 2003, 12:36am

Some Links:

Sumatriptan overuse in episodic cluster headache: lack of adverse events, rebound syndromes, drug dependence and tachyphylaxis. (http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11062845&dopt=Abstract)

The same article in the OUCH library. (http://www.clusterheadaches.org/library/medications/imitrex_rebound.htm#1)

and

Use of high sumatriptan dosages during episodic cluster headache: three clinical cases. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8707559&dopt=Abstract
)

PFNADs
Ueli

Title: Re: The Imitrex "limit"
Post by Karla on Nov 10^th, 2003, 5:36am

I found that when I went off imitrix after using it at high doses for a couple of years that I was able to relate it to the anxiety attacks I was having.

Title: Re: The Imitrex "limit"
Post by Boots on Nov 10^th, 2003, 5:46am

Befor using the trex tip I would get hit mid cycle with 6 to 8 ha's in 24 hours doing a full 6mg dose each time.
Trex clears out of your system in 2 hours.Now using trex in vials to get 3mg dose and ha only lasting 6 to 8 min,but still getting 6 to 8 ha's mid cycle...

--------Bill

Title: Re: The Imitrex "limit"
Post by Unsolved on Nov 10^th, 2003, 9:55am

Thanks to you all for your responses !! And Ueli ... thanks for the links ( I did read them) ... very helpful :)

I hate that others have to do it too (take more than the 'limit'), but at least i'm not alone.

I read somewhere that chemicals in Imitrex binds to the eyes. That using lots of it can cause vision problems. Has anyone else read this to ?

Unsolved
Wishing you all PFD&N

Title: Re: The Imitrex "limit"
Post by sixtyminuteman on Nov 10^th, 2003, 12:47pm

I've been lucky, I guess. I've gotten pretty good relief using 25mg tablets. Damned expensive though, and when the ha's are frequent, I have used up the 9 tablets/pkg a day before my insurance company will pay their share for a refill, so I have to 'go naked' for 24 hours. OUCH!

Title: Re: The Imitrex "limit"
Post by Prense on Nov 10^th, 2003, 1:55pm

on 11/10/03 at 09:55:49, Unsolved wrote:

I read somewhere that chemicals in Imitrex binds to the eyes. That using lots of it can cause vision problems. Has anyone else read this to ?

First I have heard about that UE...

That was a concern when I was taking Topamax though.

Title: Re: The Imitrex "limit"
Post by Tiannia on Nov 10^th, 2003, 3:58pm

on 11/10/03 at 12:47:16, sixtyminuteman wrote:

My insurance will only pay for 9 50mg tabls every two weeks, At this point I cut them in half or thirds if I can to try and make them last longer, as I can not afford to by them myself w/o insurance. And if I can take them right when I start getting that bad shadow and getting the sweats, then it will help, if not then I an screwed and praying for it to stop.

Tia

Title: Re: The Imitrex "limit"
Post by LSUnut on Nov 10^th, 2003, 4:55pm

I have read a few articles pertaining to the frequent use of triptans and their affect on vision, I don't, however, believe that the drug itself is binding to some part of the eye. I'm a medicinal chemist and I am very familiar with the hoops and red tape involved with getting a drug to market (average time is 10 years from conception to consumer). Many drugs can cause side-effects like blurred vision or drowsiness, but if any of the triptans were believed to cause or potentially cause permanent vision problems, there is no way they would have received FDA approval. This is based on the simple fact that migraines and clusters are not considered life-threatening, so blindness is not a good trade-off. All of this is not to say that the triptans can't affect your vision, though. The FDA safety standards follow a therapeutic index of when the maximum therapeutic benefit has been reached at the lowest dosage. For example, if 25mg of imitrex relieves more than 50% of the pain in 50% or more of the patients, but 50mg (a doubling)of imitrex only does slightly better and not a full doubling of the beneficial results, then they will recommend the lower dose. They also have to follow a similar index in reverse to plot the increase and severity of side-effects. They have to carefully determine when, in most individuals, will the benefits of taking the med no longer outweigh the risks. From my own personal knowledge of the triptans and how they work, I think that excessive usage, especially in higher dosages, could turn out to be a very dangerous practice. Being a fellow CH sufferer, I know the pain and desire to make it stop, but I only use Zomig or Imitrex as a last resort before a potential ER trip. Triptans cause very focussed vasoconstriction of the extracerebral blood vessels. If you are constantly dosing yourself, then you are potentially starving tissues supplied by those blood vessels. You are also causing a spike (upward) in blood pressure in that area, constantly (think; stroke, cerebral hemorrhage, embolism). The FDA nor the drug companies have examined this in depth to produce accurate data, hard to get volunteers I guess, but the triptans have been linked to some deaths. The same type of problems have occured with other focalized vasoconstrictors, like Afrin. Some people who got hooked on Oxymetazoline and its powerful decongesting ability by vasoconstriction ended up with necrotic tissue in their sinus cavities. This isn't to frighten you, but please be careful and remember that Imitrex and the other triptans are very powerful drugs. Wishing you PFDAN.. ;)

Title: Re: The Imitrex "limit"
Post by Prense on Nov 10^th, 2003, 7:16pm

on 11/10/03 at 16:55:38, LSUnut wrote:

Many drugs can cause side-effects like blurred vision or drowsiness, but if any of the triptans were believed to cause or potentially cause permanent vision problems, there is no way they would have received FDA approval. This is based on the simple fact that migraines and clusters are not considered life-threatening, so blindness is not a good trade-off.

If I am recalling correctly, the topamax I was taking had a crystal clear warning that it can cause permanent eye damage. I forget exactly what they call it.

What you are saying makes sense in a logical way, but some people are willing to risk death and permanent injuries/paralysis on the chance they may improve quality of life...kind of a live for the moment type thing. That is why these operations for CH still happen even with the risks. They don't call these things suicide headaches for nothing.

My [smiley=twocents.gif]

Chris

Title: Re: The Imitrex "limit"
Post by sixtyminuteman on Nov 11^th, 2003, 10:54am

Quote:

And if I can take them right when I start getting that bad shadow and getting the sweats, then it will help, if not then I an screwed and praying for it to stop.

Yes, this is what I find as well. Currently, I'm down to 1 HA a day, at midnight (down from2-3/day). If I pop a 25 mg pill as soon as I wake up, it either gets rid of the HA in 5-10 min, or it mitigates the HA so I can endure it. I am on my 4th pkg of 9, over the last 6 weeks.

Good luck to everybody.

Title: Re: The Imitrex "limit"
Post by LSUnut on Nov 11^th, 2003, 11:21am

You are correct, Topamax has been linked to permanent vision problems. These problems are usually associated with myopia and/or closed-angle glaucoma. The evidence is not crystal clear, however, because many drugs that can potentially cause an increase in itraocular pressure can cause vision problems, and the symptoms often go away when the drug is discontinued. On the other hand, different forms of mild glaucoma are often asymptomatic until the condition worsens (say from the use of a particular drug). So, the real issue for most patients is to discontinue the drug as soon as adverse reactions occur in order to prevent permanent damage. Getting back to the issue, though, Topamax is not a triptan nor was it even designed as a headache medicine. Topamax is a powerful anti-epileptic designed to prevent and control partial seizures and grand mal seizures (which, unfortunately, are often life-threatening), so the FDA is more lenient when considering at what point the benefits no longer outweigh the risks. Depakote was also designed as an anti-epileptic, it just happens to help as a preventative for some headache sufferers (its side-effects can also be quite severe). Back to the triptans, though, some of the animal testing (I believe in rats) did reveal that imitrex or one of its metabolites bound to the melanin in eye pigments. This was never seen during the human trials, most probably because the elimination half-life in humans is very short (roughly 2 hrs). Also, there is a good chance it was a metabolite and not the actual drug, meaning it could be a metabolite that humans don't produce. They also report corneal cloudiness/opacity (cataract formation) in the eyes of dogs. This information is not earth-shattering, however, because dogs tend to form cataracts very easily and usually without any known etiology. Sorry to be so lengthy, but I hope this info helps. ;)