Phenobarb levels

RE: Phenobarb levels

Anthony Todd — Tue, 31 Oct 2017 09:56:22 GMT

[quote user="Anthony Todd"]

[quote user="Anthony Dennison"]Had to increase the phenobarb dose to 90mg BID,[/quote]

[This'll blow many minds]

This is one where I'd test the blood level [only to find that the dog, obviously, isn't getting the prescribed dose......]

not impossible....

[/quote]

This is a classic example of a malicious, pointless one star which, in the past, I have enhanced to see if my post was deserved of one star.

Dosage compliance is a real possibility here!

What purpose does this anonymous one star serve anyone??

RE: Phenobarb levels

Clive Ansell — Tue, 31 Oct 2017 09:42:57 GMT

[quote user="David Mills"]

I went on some cpd a while ago led by a specialist.

Their advice about phenobarb was they hardly ever test it if seizures are controlled and never bother with liver levels (always raised, not toxic, just upregulation of enzyme activity).

They start phenobarb when one seizure a month or more, 3mg/kg.

They MRI about 1 every 1000 if that.

Seems eninently sensible.

[/quote]

Some things don't really change - this is what I was taught 20 - 25 years ago, including some seeing practice as a student with a referral neurologist. It had worked for me ever since.

I like to keep a tab on phenobarb levels with 6 - 12 monthly bloods, particularly the more difficult to stabilise cases.

MRI seem to be more fashionable, but I almost never advise it unless a progressive or difficult case, or if a neurological exam indicates it. I have had some clients demand it though.

RE: Phenobarb levels

David Mills — Tue, 31 Oct 2017 00:59:37 GMT

I went on some cpd a while ago led by a specialist.

Their advice about phenobarb was they hardly ever test it if seizures are controlled and never bother with liver levels (always raised, not toxic, just upregulation of enzyme activity).

They start phenobarb when one seizure a month or more, 3mg/kg.

They MRI about 1 every 1000 if that.

Seems eninently sensible.

RE: Phenobarb levels

Julie Innes — Mon, 30 Oct 2017 21:08:52 GMT

I've actually just done a webinar tonight (just by coincidence!) On decision making in neurology. Much of it was to do with surgery vs conservative treatment, but the speaker (Dr. Peter Early) did talk about phenobarbital and refractory epilepsy. He defined refractory epilepsy as "a dog on 2 or more drugs in the therapeutic range which is still having 1 or more seizures per month). He also spoke about when to add a second drug (something I think has been discussed here) and he said that if the phenobarbital levels were more than 30 he would add a second drug rather than increase the phenobarb (I think the high end therapeutic level is around 44- could be wrong, don't shoot me if I am!) as his experience was that simply increasing the phenobarb was less successful. Unfortunately he said nothing about routine monitoring (and it was a recorded webinar, so I couldn't ask!) but still relevant to some of the points here

RE: Phenobarb levels

Neil Wheadon — Mon, 30 Oct 2017 20:36:42 GMT

[quote user="Thomas Johnson"] maybe posting less frequently and putting all of your points in to one post?[/quote]

Well that worked didn't it

Neil

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 19:57:57 GMT

Duplicated for no reason??

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 19:56:51 GMT

[quote user="Anthony Dennison"]Had to increase the phenobarb dose to 90mg BID,[/quote]

[This'll blow many minds]

This is one where I'd test the blood level [only to find that the dog, obviously, isn't getting the prescribed dose......]

not impossible....

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 19:36:28 GMT

Fair do's will comply.

RE: Phenobarb levels

Thomas Johnson — Mon, 30 Oct 2017 19:09:49 GMT

[quote user="Anthony Todd"]

[quote user="Neil Wheadon"]but less is more[/quote]

Or rather challenge is unacceptible?

[/quote]

I imagine that most of us, when we read a post that we want to reply to, reply straight away. For most of us at work we probably read the forums 2 or 3 times during the day, and may not catch up on all of the posts in one go, so there's not many opportunities for us to write posts. I suspect that as you are retired you are on here far more frequently, and have far more opportunities to post. What the answer is to this I don't know, because you should be able to write whatever you want, maybe posting less frequently and putting all of your points in to one post?

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 18:43:26 GMT

[quote user="Neil Wheadon"]but less is more[/quote]

Or rather challenge is unacceptible?

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 18:07:56 GMT

[quote user="robloxley"]

[quote user="Anthony Todd"]There have been extensive previous threads on this.[/quote]

Where everyone still disagreed with you?
The ACVIM Consensus Statement is still to be found at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4913615/pdf/JVIM-30-477.pdf

[/quote]

So I looked again just now but stopped early on after this paragraph with reference numbers deleted to make it more concise!!

Although similar information is not as readily available for dogs, extrapolation can provide rational treatment guidelines. Overwhelming evidence exists in people that there is no benefit to starting treatment after a single unprovoked event. The earlier AED treatment is started; however, the better the potential outcome may be for seizure control. Recurrent epileptic seizures can increase epileptogenesis and drug resistance in a subgroup of patients. Prolonged and acute repetitive seizures can increase patient morbidity and require prolonged hospitalization with associated financial burden. Comparable information is not available for dogs.

So to start:

Overwhelming evidence exists in people that there is no benefit to starting treatment after a single unprovoked event.

Which is similar to current veterinary advice !

But in the next sentence!!!!

The earlier AED treatment is started; however, the better the potential outcome may be for seizure control. Recurrent epileptic seizures can increase epileptogenesis and drug resistance in a subgroup of patients.

and, to cap it all!!

Comparable information is not available for dogs.

but the paper goes on to recommend 2 seizures in 6 months before treatment.....??

Don't people, or authors actually read citations?

RE: Phenobarb levels

Neil Wheadon — Mon, 30 Oct 2017 17:40:57 GMT

[quote user="Anthony Todd"]Turboposting, for a start! Please define this to me 'cos I don't think I turbopost unless a similar reply to the same topic, in different threads is the definition.[/quote]

Look at the first page of this discussion

Anthony Todd 7 The rest 8

Sounds like a rugby result, that's turboposting. What happens in my opinion is that the discussion goes nowhere fast, all folks are doing is replying to your points (unless you beat them to it )

It's a very interesting topic and I read the last one and you do provoke debate, but less is more

Neil

RE: Phenobarb levels

Anthony Todd — Mon, 30 Oct 2017 17:22:56 GMT

[quote user="Neil Wheadon"]

It would make a good topic of the month, though with respect Anthony, turbo posting would detract from it

Neil

PS I don't one star either, though boosting any one stars yourself isn't cricket. The logic that 'I'm right, therefore I don't deserve that' is a bit bizarre.

[/quote]I vowed and declared i wouldn't bother again at all but, as there seems to be sensible conversation, raising points I can discuss I'll begin again.

Turboposting, for a start! Please define this to me 'cos I don't think I turbopost unless a similar reply to the same topic, in different threads is the definition.

I add stars sometime to see for myself if the phantom one starrer will supply a reasoned response or someone will agree with the one star.

Sometimes when I'm wrong the one star, and with reasons, returns, fair enough, other times more stars stay so I believe what I've said is probably Ok...

It seems to me that "turboposting" is applied to anyone who replies in an unpopular way [eg corticosteroids every time...]

RE: Phenobarb levels

Anthony Dennison — Mon, 30 Oct 2017 16:27:44 GMT

[quote user="Thomas Johnson"]

On the other hand if seizure control has got worse in a dog that was previously well controlled on phenobarb, rather than increasing the dose I would probably now split the same daily dose every eight hours rather than every twelve hours based on this paper:

http://veterinaryrecord.bmj.com/content/180/7/178

[/quote]

That's really interesting actually - I'm currently trying to control a Border Collie that was in such bad status epilepticus she was on a propofol CRI for about 12 hours. Had to increase the phenobarb dose to 90mg BID, the dog is on Levetiracetam and now KBr too. Owner is worried about stopping levetiracetam (I want to reserve it for breakout seizures as recommended on here previously), so possibly using this dosing regimen will help

RE: Phenobarb levels

Thomas Johnson — Mon, 30 Oct 2017 16:02:59 GMT

[quote user="Julie Innes"]

Ok, this is interesting, and I'm prepared to revise my protocol if necessary, but I was taught that the blood level of phenobarbital could change over time as the liver can either become more efficient at metabolising it, or become damaged and less efficient, so you should check levels a couple of times a year to make sure you were still delivering a suitable dose. Obviously in dogs that have increased seizure activity I would check, or if they were showing signs of toxicity. But the difficulty with dogs that aren't having seizures is that you don't know they wouldn't be having seizures even without the drugs! I'd rather my dog had 2 seizures a year than be on long term phenobarbital. But as I said, I am prepared to be educated!

[/quote]

I guess the question is what are you going to do if the dog's seizure control hasn't changed, but it's blood phenobarb levels have. I guess if the levels have increased significantly you might consider reducing the dose, but if the levels have fallen I probably wouldn't do anything.

http://veterinaryrecord.bmj.com/content/180/7/178

RE: Phenobarb levels

Neil Wheadon — Mon, 30 Oct 2017 12:30:46 GMT

It would make a good topic of the month, though with respect Anthony, turbo posting would detract from it

Neil

PS I don't one star either, though boosting any one stars yourself isn't cricket. The logic that 'I'm right, therefore I don't deserve that' is a bit bizarre.

RE: Phenobarb levels

vs0u — Mon, 30 Oct 2017 10:56:43 GMT

I'm not the one starrer either.

Anthony, have you the linked paper linked by robloxley above? What do you think of it? I don't think it's radically different from anything you are saying, more a refinement since new research has come to light. It explains the rationale behind the blood testing etc quite logically.

RE: Phenobarb levels

Julie Innes — Sun, 29 Oct 2017 20:54:50 GMT

I find this discussion interesting and useful. Please be sure I am am not the phantom one starrer here, Anthony.

RE: Phenobarb levels

Anthony Todd — Sun, 29 Oct 2017 18:15:59 GMT

RE: Phenobarb levels

Nicola Cole — Sun, 29 Oct 2017 17:37:37 GMT

With all due respect I think during the last few posts you may be talking about slightly different things.

The '2 fits in 6 months' thing is not to do with what level of fitting you're trying to get things down to on medication. It is an indicator of WHEN to start medicating i.e. if the dog has one fit lasting 30 seconds then medication would not be started instantly. If the dog then had a second fit within the next 6 months then the advice is to start medicating.

RE: Phenobarb levels

Anthony Todd — Sun, 29 Oct 2017 17:29:41 GMT

Dear one starrer.

Thanks for your comprehensive review of my post, together with your helpful advice.

It really is encouraging for an old dinovet to realise that, even in this age of EBVM, there is still such

a receptive acceptance of anecdote based advice for a condition that has been treated in the way I

have described, and totally successfully, cheaply and effectively by most caring veterinary surgeons

for much longer than you have been able to click a mouse.

RE: Phenobarb levels

Anthony Todd — Sun, 29 Oct 2017 17:06:44 GMT

[quote user="vs0u "]All owners I've dealt with have been happy with that (Talking about otherwise healthy animals, as per the linked paper). Who wants their dog on a long term treatment with all the costs, hassle and side effects, when they may never have another fit or may only have them occasionally?[/quote]

My experience is rather different in that owners found even one fit very distressing whereas, say a serious heart murmur, could be coped with relatively calmly.

What I didn't explain was, always, the initial dose rate or treatment stopped the fits and was adjusted so that the animal didn't fit again in that episode.

Gradually after a high dose week or so the dose was reduced, to the level which just prevented fitting and then tapered over a month or so if there were no more.

Many dogs needed to be on the lowest preventative dose for ever though it used to be adjusted regularly.

We never had dogs fitting "twice in 6 months", after dose stabilisation, ever!

Phenobarb used to be very cheap before the VMD when we had to use licenced product......

Once the dose was found the only side effect was creeping obesity unless the diet was adjusted.

Adjusted the dose based on the demeanor of the animal which is obviously the best criterion, apart from avoiding the now mandatory blood levels.

All owners I've dealt with have been happy with that,

RE: Phenobarb levels

vs0u — Sun, 29 Oct 2017 14:14:24 GMT

[quote user="Anthony Todd"]

[quote user="vs0u "]I thought 2 seizures in 6 months was standard advice for when to start treatment? [/quote]

I doubt if any owner would be happy with that! We always aimed for no fits and minimal sedation at the lowest "no fits" dose rate.

[/quote]

All owners I've dealt with have been happy with that (Talking about otherwise healthy animals, as per the linked paper). Who wants their dog on a long term treatment with all the costs, hassle and side effects, when they may never have another fit or may only have them occasionally?

RE: Phenobarb levels

Julie Innes — Sun, 29 Oct 2017 13:18:28 GMT

RE: Phenobarb levels

Anthony Todd — Sun, 29 Oct 2017 11:48:49 GMT

[quote user="vs0u "]I thought 2 seizures in 6 months was standard advice for when to start treatment? [/quote]

I doubt if any owner would be happy with that! We always aimed for no fits and minimal sedation at the lowest "no fits" dose rate.