Onychodystrophy - Vitamin B?

Re: Onychodystrophy - Vitamin B?

Anonymous — Tue, 12 Apr 2011 17:35:06 GMT

Reported side effects at these therapeutic doses are generally adverse GI effects (normally mild if occur); the following are listed in our practice small animal pharmacology text (Small Animal Clinical Pharmacology, 2nd ed. Eds Maddison et al. 2008): anorexia, vomiting, diarrhoea, elevated liver enzymes, hyperexcitability, depression, lameness (and apparently these are largely blamed on the nicotinamide part of the combination rather than the tetracycline).

The reason to avoid nicotinic acid / niacin is that it reportedly causes vasodilation at the (high) therapeutic dosage levels.

Only used tetracycline/nicotinamide combo a couple of times that I can remember - both for suspected lupoid onychodystrophy (though without actually sacrificing a toe to get a H/P diagnosis as to what the cause of generalised nail loss actually was). Would probably need to ask a dermatologist to find out if this is still common practice or if immunosuppressive doses of glucocorticoids are just as / more effective. Suspect only a referral dermatologist would have any serious experience of a large enough number of cases treated to be able to draw useful anecdotal conclusions, but for what it's worth I think one of the cases did well and the other did OK (while managed with alternate day paxcutol/malaseb - after doing sellotape cytology - foot bathing and some other treatments/supplements I think, but can't remember any more details now!)

Re: Onychodystrophy - Vitamin B?

Alice Courtney — Mon, 11 Apr 2011 10:29:08 GMT

Thanks for your replies, I'll look into the Lamberts supply & see how expensive it is for this dog. What side effects should I look out for in a dog, and has anyone had much experience of using this?

Re: Onychodystrophy - Vitamin B?

Stephen Courtney — Fri, 08 Apr 2011 21:21:59 GMT

B vitamins are water soluble and pretty much impossible to overdose on without going to extreme lengths assuming reasonable renal function.

I would suggest giving approximately what you would take yourself, in a deficient state / period of increased metabolic demand, i dount it could do any harm but best to get that waiver / informed consent thingy signed.

Re: Onychodystrophy - Vitamin B?

Richard Fox — Fri, 08 Apr 2011 16:19:57 GMT

Hmm - good old disease this one as no one knows what it really represents and thus the treatment protocols vary widely as do their efficacy!

Re: Onychodystrophy - Vitamin B?

Anonymous — Fri, 08 Apr 2011 11:30:04 GMT

Just looked this up and would probably stick to 500mg q8hrs even though giant breed dog - at least until happy no side effects on that dose.

Apparently a 3 month trial of this and a tetracycline are commonly recommended to decide if effective or not; if effective then decrease to q12hrs for 2mths, then q24hrs; if no relapse on once daily therapy, niacinamide is withdrawn and tetracycline cont'd.

Haven't looked up reports of clinical efficacy, but apparently it is thought to block mast cell degranulation and inhibit protease release from leukocytes, while the tetracycline suppresses complement activation, antibody production, leukocyte chemotaxis, PG synthesis and production of lipases and collagenases. TC may also inhibit NOS and augment COX-2 and PGE2 production by macrophages, as well as inhibiting MMPs and blocking angiogenesis...

before someone else says it, prednisolone (e.g. 2mg/kg q24hrs) might well also do most of these things :-)

Re: Onychodystrophy - Vitamin B?

Anonymous — Fri, 08 Apr 2011 11:08:24 GMT

Don't know if proof it helps, but tend to give Nicotinamide=niacinamide=vitaminB3 (NOT nicotinic acid/niacin)

Dose of 500mg q8hrs in large dog usually, but would probably try 750mg in a dog this heavy.

Only costs a few pounds from Lamberts (https://www.lambertshealthcare.co.uk/?), but veterinary wholesaler might charge you 10 times this price, so in a dog this size probably worth the effort of buying elsewhere...