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August 2020:  we now understand (until more in-depth research comes along) that SID (small intestinal dysbiosis) in EPI dogs and cats is not something that can be easily fixed, but rather just well managed with proper treatment that may vary from one pet to another. Although with EPI, the SID can be so out-of-control that we want and often need to do something to relieve the excessive loose stools, etc. from SID. But before automatically treating with an antibiotic, (which would be Tylosin Tartrate as it is now recommended to avoid Metronidazole if possible)… it is prudent to first try Prebiotics or Prebiotics with Probiotics.

If one has to use Tylosin Tartrate antibiotics to treat SID, approximately halfway thru the Tylosin Tartrate regimen, introduce a Pre & Probiotic product to the regimen also.

January 2020:  Tylosin  (Tylosin Tartrate/Tylan) is now listed in WSAVA (THE WORLD SMALL ANIMAL VETERINARY ASSOCIATION)  “List of Essential Medicines for Dogs and Cats”

8.Erythromycin or tylosin

These macrolides are recommended for treatment of severe Campylobacter infections and chronic enteric infections responsive to antimicrobial therapy.

Tylan Antibiotic (Tylosin Tartrate)

Currently the antibiotic of choice to treat SID in EPI patients is Tylan (Tylosin Tartrate 100 grams- -given according to weight / 30-45 day course given every 12 hours (breakfast & dinner). In some cases the dose may be split into 3 daily doses vs. 2 daily doses if optimal results are not being achieved. If Tylan does nothing within a week, THEN try a different antibiotic. Some of the other options are Amoxycillan, Oxytetracycline (Oxytet), etc.

Oxytet  (UK alternative) Scroll to the bottom of this page for the revised 2016 UK Oxytetracycline dosing recommendation. Should be given on an empty stomach and 1 to 2 hours prior to a meal.

Tylan (Tylosin Tartrate)  Dosing chart


Tylan (Tylosin Tartrate) Dosage Guide

13kg/30 lb – 1/8 tsp
27kg/60 lb – 1/4 tsp
41kg/90 lb – 3/8 tsp
54kg/120 lb – 1/2 tsp
twice per day

The effects of Tylan on SID (SIBO)

The following are May 2013 photo’s of Cristina’s EPI dog, Sadie’s poo before and after treatment with Tylan for SIBO:

Sadie’s poo prior to treatment with Tylan:




Sadie’s poo after 1 week on Tylan:





**Please scroll down for links for availability of Tylan in various countries outside of the USA ** 

The following are veterinarian research articles with regards to Tylan

November 2019 Long Term impact of TYLAN on dogs research:

Tylosin reserach 11-2019


December 2017  Effects of Tylan on SID research:

Effect of Tylan on SID


SID (SIBO/ ARD) ….Tylan…………2011 previously

by: Dr. Elias Westermarck

Tylosin-responsive diarrhea


Tylosin-responsive diarrhea (TRD) is a syndrome that includes all cases in which tylosin antibiotic treatment has had a positive effect on treating dogs with intermittent or chronic diarrhea. Antibiotic treatment often leads to resolution of clinical gastrointestinal (GI) signs, and thus the term antibiotic-responsive diarrhea (ARD) was coined. Recently, trials have been published in which tylosin proved to be particularly effective in treating dogs with chronic or intermittent diarrhea, with the effect of tylosin differing from that of other antibiotics, thus indicating that the more newly established term TRD is more appropriate than ARD.

Tylosin antibiotic

Tylosin is a macrolid, bacteriostatic antibiotic that has activity against most Gram-positive and Gram-negative cocci, Gram-positive rods and Mycoplasma. However, the Gram-negative bacteria Escherichia coli and Salmonella spp. are intrinsically tylosin-resistant. Tylosin is used only in veterinary medicine, and its most common indications are treating pigs with diarrhea or poultry with chronic respiratory diseases. Tylosin has also been used as a feed additive in food animal production, and it has been shown to increase gain and feed efficiency, especially in pigs. Debate about the mechanisms underlying tylosin-mediated growth enhancement is ongoing.

Tylosin is usually used in powder form for pigs and poultry. In Finland and in some other countries, tylosin is also available in tablet form, facilitating its use in dogs.

Experiences of tylosin in treating diarrhea

Our experience with tylosin is derived from numerous studies with dogs suffering from exocrine pancreatic insufficiency (EPI).These studies have clearly shown that tylosin has a favorable effect as a supportive therapy on dogs with EPI.

In Finland, tylosin has for years been the most common drug in the treatment of unspecific intermittent or chronic diarrhea in dogs. Anecdotal reports by veterinarians and dog owners reveal that many dogs with diarrhea respond well and quickly to tylosin treatment, generally within a few days of initiation of treatment. When treatment is discontinued, however, diarrhea reappears in many dogs within a matter of weeks or months. Some dogs need a treatment over very long period. Even so, the effect of controlling diarrheal signs does not appear to diminish with time, and thus there is no need to increase the dosage of the medication. No apparent tylosin-associated adverse effects have been reported.

TRD can affect dogs from all breeds and ages but is most often seen in middle-aged, large-breed dogs. The diarrea signs appear often as intermittent but progressivly become more frequent and end as persistent diarrhea. Abnormal loose fecal consistency is the predominant sign. The majority of the owners describe their dogs’ feces as watery and/or mucoid indicating that TRD affects both the small and large bowel. Increased frequency of borborygmus and flatulence are also typically seen. Vomiting is occasionally seen during the diarrheal outbreaks.

In dogs with TRD the blood parameters are usually normal. Also the abnormal findings in diagnostic imaging studies and histological examination of intestinal biopsies, are only mild or completely absent.

Clinical studies with tylosin

Only a few studies on treating diarrheal signs in dogs with tylosin have been published. Van Kruiningen, (1976) reported more than 30 years ago that tylosin had a good effect in treatment of unspecific canine diarrhea. Recently, our study group performed two clinical trials to obtain more information on TRD. The first study included 14 adult pet dogs of 12 different breeds. Each dog’s diet remained unchanged throughout the study. The dogs had shown chronic or intermittent diarrheal signs for a period of more than one year. Diarrhea had been successfully treated with tylosin for at least six months, and the treatment had been discontinued at least twice but the signs had always occured. When the study commenced, all dogs had been on tylosin for at least one month and were otherwise healthy. Thereafter, tylosin was discontinued and the dogs were monitored for a period of up to one month to determine whether signs of diarrhea would reappear, as suggested by the clinical history. Diarrhea reappeared in 12/14 dogs (85.7%) within 30 days. During the treatment trial diarrhea ceased with tylosin in all dogs within three days and in most dogs within 24 hours. In contrast, prednisone did not completely resolve diarrheal signs, and the probiotic Lactobacillus rhamnosus GG did not prevent the relapse of diarrhea in any of the dogs.

In the second study in an experimental dog colony, seven beagles showed signs of chronic diarrhea for at least one month. The dogs were treated with tylosin for ten days. During the treatment period the feces became significantly firmer, although they remained unacceptably loose. When the treatment was discontinued, diarrhea reappeared within three weeks. Treatment with other antibiotics (metronidazole, trimethoprim-sulfadiazine, or doxycycline) or with prednisone had almost no effect on fecal consistency, the feces remaining abnormally loose in all dogs. The diet was then changed for a ten-day period from a highly digestible moist pet food to a dry food developed for normal adult dogs. The feces again became significantly firmer, although they remained loose in some dogs. The dry food period was then extended to three months, but the fecal consistency continued to fluctuate from ideal to diarrhea. Since the consistency was not satisfactory, the dogs were treated a second time with tylosin for ten days. The feces then became normal in consistency and remained so throughout the entire three-month follow-up time. The study revealed that in the experimental dogs with chronic diarrhea the fecal consistency became significantly firmer both with tylosin treatment and with dietary modification. Neither of the treatments alone was sufficient to obtain ideal fecal consistency, but when the dogs were treated simultaneously with both regimes, permanent ideal fecal consistency was attained. The study thus indicated that tylosin and feeding regimes have synergic effects.


The etiology of TRD remains obscure. Since tylosin is an antimicrobial agent, it has been speculated that some pathogenic bacteria are likely responsible for the diarrheal signs. Based on negative culture results and ELISA tests, we have excluded such common enteropathogenic bacteria as Clostridium perfringens, Clostridium difficle, Salmonella spp., Campylobacter spp. , and Yersinia spp. as causative factors for the diarrheal signs occurring in TRD. Less well-defined species causing diarrhea in dogs, such as Plesiomonas shigelloides, Lawsoni intracellularis, and Brachyspira spp., have also been excluded.

Our ongoing studies have revealed that administration of tylosin leads to significant but transient changes in the composition of the small intestinal microflora. The results support the hypothesis that tylosin promotes the growth of beneficial commensal bacteria, while suppressing deleterious bacteria.

Besides antibacterial properties, tylosin may possess anti-inflammatory properties, contributing to its effectiveness in treating canine diarrhea. The mode of action must differ, however, from the immunomodulatory effect of prednisone because prednisone treatment did not completely resolve diarrheal signs in the same dogs that responded to tylosin.

Diagnostic protocol for dogs with chronic diarrhea

The diagnostic protocol used for dogs with chronic diarrhea by the Faculty of Veterinary Medicine, University of Helsinki, is represented in Figure 1. In patients with chronic diarrhea, every effort should be made to achieve a diagnosis to enable a specific therapy. Unfortunately, this is not always possible in which case empirical therapeutic trials are used in the workup of these patients. There are conflicting opinions about how long an empirical therapy should be attempted. We recommend ten days if a dog has chronic diarrhea or if the interval between intermittent diarrheal episodes is only a few days. If signs of diarrhea disappear or are relieved during this period, the treatment should be continued another 2-6 weeks. When the interval between episodes of intermittent diarrhea is long, i.e. more than one week, the length of the empirical treatment period should be prolonged. The workup protocol displayed in Figure 1 for patients with chronic or intermittent diarrhea is applicable to most veterinary practices. It is also useful regardless of whether the clinical signs are typical of large- or small-intestine disease. The prevalence of diseases that can simultaneously affect the small and large intestines is high.

The initial evaluation (A) comprises obtaining a thorough case history (A1), conducting a physical examination (A2), and taking the basic laboratory tests, including a complete blood count, a serum chemistry profile, and measurement of serum concentrations of trypsin-like immunoreactivity (TLI) (A3). According to the initial examination, the patients are then divided into two groups. The first group includes patients showing clinical abnormalities in addition to diarrhea (Group B), while the second group shows no obvious abnormalities other than diarrhea (Group C).
Patients with obvious abnormalities (B) suffering from systemic disorders with secondary diarrhea (B1a), such as hepatic failure, renal failure, hypoadrenocorticism, and EPI (B1b), should be identified before starting trial therapies. Also if hypoproteinemia (B1c), melena and/or anemia (B1d), or abnormal palpation findings (B1e) are found, the reason for these abnormalities should be examined.
Dogs with diarrhea but no other abnormalities (C) are treated orally with fenbendazol 50 mg/kg for three days (C1) to rule out endoparasites as the causative factor for GI signs.

Food is probably the most common cause of diarrhea (C2), and adverse food reaction should always be excluded before empirical treatment trials with different drugs are initiated. Opinions vary widely about how the diet should be changed for a dietary treatment trial. Unfortunately, current recommendations are largely based on anecdotal evidence rather than on controlled trials. The most common recommendation is to use a diet with novel protein and carbohydrate sources, with the former restricted to a single animal source.

If modifying the feeding regime fails to produce a satisfactory fecal consistency, the next step is to treat the dog with tylosin 25 mg/kg BW q24h (C3). Dogs responding to tylosin treatment will usually do so within 3-5 days, and diarrhea will remain absent as long as treatment continues. In many dogs, diarrhea will reappear within some weeks upon discontinuation of treatment. If diarrheal signs reappear, the dog owner should change the dog’s diet once again to make sure that the feeding regime is not involved in the etiology of the signs. If diarrheal signs continue, tylosin treatment is re-initiated. The effect of tylosin does not appear to diminish even in dogs that have been treated for years. The dose of tylosin for long-term use should be tapered to the lowest possible dose that controls clinical signs. Many dogs need only half of the recommended dose.

Although no adverse effects during tylosin treatment have been reported, efforts should be made to reduce the use of tylosin. This is because our recently conducted studies have indicated that tylosin causes wide resistance to antibiotics in the intestine (unpublished results). Certain probiotic lactic acid bacteria (LAB) have been shown to be effective in the prevention and treatment of a variety of diarrheal disorders in humans and in experimental mouse models. Hopefully in the future a probiotic LAB can be used instead of tylosin to treat or prevent chronic diarrhea in dogs with TRD.

With dogs not responding positively to dietary modification or tylosin treatment diagnostic imaging studies (D) should be performed and the workup continued as displayed in Figure 1.

Figure 1. Diagnostic approach to dogs presenting with chronic diarrhea at the Veterinary School in Helsinki, Finland. (click on figure to enlarge)


1. Westermarck E, Skrzypczak T, Harmoinen J, Steiner JM, Ruaux C, Williams DA, Eerola E, Sundbäck P, Rinkinen M. Tylosin-responsive chronic diarrhea in dogs. J Vet Intern Med 2005;19:177-186.
2. Westermarck E, Frias R, Skrzypczak T. Effect of diet and tylosin on chronic diarrhea in beagles. J Vet Intern Med 2005;19:822-827.
3. Westermarck E, Wiberg M. Exocrine pancreatic insufficiency in dogs. Vet Clin Small Anim 2003; 33: 1165-1179.
4. Van Kruiningen HJ. Clinical efficacy of tylosin in canine inflammatory bowel disease. J Am Anim Hosp Assoc 1976;12:498-501.


Going forward- -Tylan will only be available via prescription   

Elanco confirmed that a script will now be required to purchase Tylan Powder in all USA states.

The FDA began an initiative in late 2013 because the label recommendation is for chickens, swine and honey bees (See FDA Regulation

(Scroll to page 40 for specific mention of Tylan USDA Residue listed as one of these drugs.)

The new required label detail is as follows:

There are multiple regulations and references on this matter with the FDA.  Please feel free to click on the links above for more detailed information.

Previous scripts required by the state of California were regulated by the state and not the FDA.

Tylan is a Bacteriostat listed in the Macrolide Antibiotic Classification.

From what we have been told, places that are still selling Tylan which do not require a script, is nothing more than the overlap in stock and once that stock is used up scripts will be required.

With regards to the generic Tylan “Tylovet”  a prescription is not required but this too may change.

Epi4Dogs is sharing this information with everyone as many purchase Tylan (tartrate) powder via a variety of on-line sources .  Many depend on Tylan to keep EPI pets at optimal health.  If you use Tylan, please have a conversation with your vet with regards to prescription Tylan  going forward. Please share with your vet the research that supports using Tylan for SID in EPI pets

Tylan made be ordered with a vet prescription from many of the online pet/pharmaceutical resources.

Lambert Vet Supply

Tylan can also be purchased at CHEWEY’s and many other dog supply online stores, a prescription is needed.





6-2020 Vet One now produces “Tylosin Tartrate” which is the same as Tylan and can be purchased with a prescription:





However…. locating a Tylan source outside the USA may be difficult.

CANADA the following are some Canadian links where Tylan can be obtained with a veterinarian’s prescription:
and / or

EUROPE  Attached is a medical list of various versions and strengths of Tylan from a European Medical Library (thank you Ann!!!!).

If you live in Europe and your vet is having difficulty locating Tylan Soluble Powder… please share this list with your vet and have your vet (and /or pharmacist) identify the most closely aligned version of Tylan to the USA source “Elanco Tylan (Tylosin Tartrate) Soluble Powder 100 grams tylosin base and for your vet or pharmacist to work out the proper dose – – as many of the Tylan products on this list are either Tylan phosphate or Tylan tartrate but also in many different strengths.

The proper dosing strength for the Elanco Tylan Soluble Powder 100 gram  is located on a Tylan Dosing Chart on this page.

If you live in POLAND …. you can get “Tylofort” 900mg/g Tylosin Tartrate 1000mg/g (mfg in Germany) or you might be able to source “Tylbian” 110mg/g. Please ask your pharmacist  or vet to do the conversion and explain how many grams / according to your dog’s weight… you need to give..  Here is one link for Tylofort: …but if you live in Poland, please just do your own search for Tylofort.






If you are in the UK….. you can get Tylan from the following places…. with a prescription from your vet




Or have your vet directly contact the Bristol Vet School for a consult in EPi and a prescription for Tylan powder for SID (SIBO).

As of April 2020 Tylan has been discontinued in AUSTRALIA

(Previously) If you are in Australia and your vet did not think Tylan is available….. they were able to contact Tylan distributors directly (see below)

Some manufacturer details for your vet if they need it (their rep should be able to get it easily. It is prescription only in Australia). Costs $80-90 and lasts ages.

Tylan Soluble 100

Elanco Animal Health.

A division of Eli Lilly Australia Pty. Ltd.

112 Wharf Road, West Ryde, N.S.W. 2114

Telephone Toll Free 1800 226 324


If you are in India..…. you have access to  2 different products of Tylosin.. BUT you will need to talk to your pharmacist or vet to re-calculate the dosage  of the TYLOMIX since even though both of these are Tylosin Tartrate products they ARE NOT the same potency as the USA Elanco’s “Tylan Powder”… hence why you will need your vet or pharmacist to re-calculate the dosage equivalent of the USA Elanco’s “Tylan Powder” for the TYLOMIX.  The TROX SOLUBLE is 50% the strength of TYLAN,

TROX SOLUBLE Powder Composition Tylosin Tartrate IP (a Virbac product)

Please note that since TROX (Tylosin Tartrate( is 50% the strength of TYLAN (Tylosin Tartrate)…. so when using the Tylan dosing chart at the top of this page, please double the dosage when using TROX. (Thank You Anuj,one of our Epi4Dogs medical student member for properly calculating the dosage of TROX, available in India!)

(if the link below does not work… please copy it and paste in your browser and then it should work)

Tylan description

 Copied from DiamondBack Pharmacy ( a Compounding Pharmacy)  website and written by Giano Panzarella: 


Tylosin is a macrolide-class broad spectrum antibiotic that’s used in veterinary medicine to treat felines, canines and livestock. However, the drug is only used as an antibiotic in the treatment of infections in livestock. In cats, dogs, and other smaller animals, it is used predominantly for its anti-inflammatory properties to treat inflammatory conditions in the bowel. As such, it is commonly prescribed to pets that are suffering from diarrhea.

How Tylosin Treats Inflammatory Conditions

Tylosin’s strong anti-inflammatory properties come from it being made from natural bacteria. The drug works by interfering with the protein-manufacturing abilities of other bacteria, and it does this while not impacting the patient’s own ability to manufacture protein. Because Tylosin is a bacteriostatic antibiotic, it doesn’t kill off the bacteria in the patient’s bowel, it simply prevents it from growing and reproducing. By limiting the growth of the bacteria, the drug helps the patient to manage the infection using his or her own immune system.

Potential Side Effects of Tylosin

Tylosin is usually very well tolerated, especially among canines, so it hasn’t been found to have a serious potential for side effects. The most common side effects reported include pain at the injection site (when Tylosin is used as an injectible for respiratory infections only), anorexia, and diarrhea (when Tylosin is used as a powder for GI infections). This drug can also cause a patient’s liver blood tests (ALT and AST) to be falsely elevated.

Tylosin Precautions & Drug Interactions

Tylosin, while shown to be safe for dogs, cats, livestock, ferrets, rabbits, birds, reptiles and even pocket pets, should not be prescribed to horses. It should be used with extreme caution in patients that are pregnant or lactating, as it has not been fully studied in that regard.

This medication is very similar to erythromycin, and as a result, if the patient is already on erythromycin, Tylosin should not be used, as cross-resistance has been shown to occur. Tylosin has also been shown to increase digoxin blood levels. Therefore, if the patient is already taking digoxin for a cardiac condition, then Tylosin should not be prescribed.

Dosage and Administration of Tylosin

Tylosin is available in powder, injectable, oral liquid, and capsule formulations. FOR GASTROINTESTINAL CONDITIONS ONLY THE POWDER OR CAPSULE FORMULATIONS SHOULD BE USED)  Because this medication has a foul taste, obtaining it from a veterinary compounding pharmacy is highly recommended, because various flavorings can be added to the formulation to make it more palatable for the patient.

Author: Giano Panzarella

*** Tylan is nasty tasting, so it can be either prepared for one at a compounding pharmacy such as DiamondBack or you can purchase the powder on-line or through your vet. ONLY THE POWDER FORM IS USED FOR SID/SIBO. There are multiple ways to camouflage the taste when giving to your dog or cat (see examples below on this page) ***

The name change…….SIBO now referred to as SID

For years we have called it SIBO (Small Intestinal Bacterial Overgrowth)…. but as more research has been THANKFULLY done….. it has been observed that there is a lot of “idiopathic SIBO” happening that does not exactly fit the SIBO criteria. So to better capture all cases of dogs and cats struggling with this condition, the veterinarian community has now renamed SIBO as SID. SID means “small intestinal dysbiosis”. Dysbiosis means that there is a microbial imbalance.


How to camouflage Tylan

Tylan is very nasty – bitter tasting… some dogs will take it mixed in their meals… others will not…

Here on the epi4dogs forum we share creative ideas… often tips on saving money.  Below is a great home-made idea by Maureen, Byrnn’s mom on how to encapsulate Tylan powder without spending a lot of money:

Thanks Maureen… great idea!










“Here is a way to get Tylan down instead of putting it in the food. My Brynn stopped eating very early on because Tylan was on her food. So I got “00” gelatin capsules from a compound pharmacy, a block of florist foam from the dollarstore (and poked holes in it with a pencil), used a cake decorator tip as a funnel and measure out 1/8 tsp Tylan per capsule. There is still some room to add a pinch more if needed. I just pop these down her throat right before her meal. ” – Maureen.

Similarly, inexpensive encapsulators and gel caps are available from health food stores or online at retailers like Amazon.

One size “00” size capsule equals 1/8 teaspoon of Tylan powder.






Metronidazole Antibiotic

Diazapam-Valium for Metronidazole toxicity


Australian Veterinarian Journal
Research supporting what Epi4Dogs has been warning about Metronidazole for years……………..

metro toxicity

Warning – a personal story with an EPI dog and Metronidazole Toxicity

In some rare cases …. some dogs “may” have an adverse reaction to Metronidazole… especially if used long-term. The treatment is to stop the Metronidazole immediately…. but Valium may also be used as an antidote to Metronidazole poisoning. The following is an actual example of an Metronidazole poisoning with an EPI dog:

Dave & Linda, owners of Sasha
August 2011

Our GSD, Sasha, was taking Metronidazole and was on her third round.  I let her outside in the late evening to do her business before bedtime.  Walking back to the house, she began to stumble and stagger, barely making it up the back porch steps.  The best way to describe her walk was as if she were in a drunken stupor.  Then when she came inside, she threw up four times.  The fact that she had a hard time standing and walking really scared us, so my husband took her to an emergency vet center since it was already 10 p.m.  After racking up a $1258 bill there, we received a call at 8 a.m. (Sasha was left there overnight) the next morning informing us our dog was getting worse, now not being able to stand at all and her eyeballs were rolling around in her head.  They suggested we come pick her up and take her to another hospital to see a neurologist.  Our poor Sasha had to be rolled out on a gourney and lifted and put in the back seat of our car.

After the 25 mile drive to the other hospital, techs lifted Sash out of our car and carried her in on a stretcher!  She laid sideways on a mat on the floor as her eyes continued to roll in her head.  It was heartbreaking, and we thought for sure we would lose her.  The neurologist suspected Metronidazole toxicity but said he wanted to rule out a brain tumor or spinal infection so told us he wanted to perform an MRI on her head and do a spinal tap. We agreed to this but are always hesitant about anesthesia, especially with a dog in this condition.

This is where we made another costly mistake.  In retrospect, looking up the side effects of Metronidazole, a rare side effect is built-up toxicity from it, of which Sasha had the exact symptoms – vomiting, unable to walk or stand, disorientation, the eyes rolling.  Time and Valium is the antidote

The MRI and spinal tap came back normal. so the vet started Sasha on Valium, and within 24 hours she made a remarkable improvement.  We picked her up the next day and could not believe that was the same very sick dog we left there, as she waked right up to us with her tail wagging!

This was a $3,900 lesson.  My point is if your pet is on Metronidazole and you notice any side effects that affect the central nervous system, Stop the metro immediately.  Go to your vet for the Valium.  We could have saved a lot of money if we would have gone this route at first.  If after a day of the Valium there was no improvement, then the MRI and spinal tap would have been needed.

Hope our story helps someone.  These scary and horrible side effects from the Metronidazole are rare, but they do happen, so be mindful of them if you pet is on this medication.  I am also happy to add that Sasha doesn’t appear to have any residual effects and was totally  back to her normal self within a few days.

Since this story there have been approximately 5 cases of Metro toxicity/poisoning from members on the Epi4Dogs Forum.  Although easily reversed, some vets are now opting not to use Metronidazole if there is another option.

Oxytetracycline Antibiotic

Oxytetracyline (Oxytet) is available and often used in the UK in lieu of Tylan.  THe following is the dosing recommendation put forth 2016 by UK Animal Care:

Oxy dosing