Tulissin 25® (tulathromycin injection) Injectable Solution

25 mg of tulathromycin/mL
For use in suckling calves, dairy calves, veal calves, and swine. Not for use in ruminating cattle.

CAUTION: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian.

TULISSIN 25 Injectable Solution is a ready-to-use sterile parenteral preparation containing tulathromycin, a semi-synthetic macrolide antibiotic of the subclass triamilide. Each mL of TULISSIN 25 contains 25 mg of tulathromycin as the free base in a 50% propylene glycol vehicle, monothioglycerol (5 mg/mL), citric acid (4.8 mg/mL) with hydrochloric acid and sodium hydroxide added to adjust pH. TULISSIN 25 consists of an equilibrated mixture of two isomeric forms of tulathromycin in a 9:1 ratio.

The chemical names of the isomers are (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[[2,6-dideoxy-3-C-methyl-3-O-methyl-4-C-[(propylamino) methyl]-α-L-ribohexopyrano-syl]oxy]-2-ethyl-3,4,10-trihydroxy-3,5,8,10,12,14-hexamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-ß-D-xylo-hexopyranosyl]-oxy]-1-oxa-6-azacyclopentadecan-15-one and (2R,3R,6R,8R,9R,10S,11S,12R)-11-[[2,6-dideoxy-3-C-methyl-3-O-methyl-4-C-[(propylamino)methyl]-α-L-ribohexopyrano-syl]oxy]-2-[(1R,2R)-1,2-dihydroxy-1-methylbutyl]-8-hydroxy-3,6,8,10,12-pentamethyl-9-[[3,4,6-trideoxy-3-(dimethylamino)-ß-D-xylohexopyranosyl]oxy]-1-oxa-4-azacyclotridecan-13-one, respectively.

Swine

TULISSIN 25 Injectable Solution is indicated for the treatment of swine respiratory disease (SRD) associated with Actinobacillus pleuropneumoniae, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis, and Mycoplasma hyopneumoniae; and for the control of SRD associated with Actinobacillus pleuropneumoniae, Pasteurella multocida, and Mycoplasma hyopneumoniae in groups of pigs where SRD has been diagnosed.

Suckling Calves, Dairy Calves, and Veal Calves

BRD - TULISSIN 25 Injectable Solution is indicated for the treatment of bovine respiratory disease (BRD) associated with Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis.

Swine
Inject intramuscularly as a single dose in the neck at a dosage of 2.5 mg/kg (1 mL/22 lb) Body Weight (BW). Do not inject more than 4 mL per injection site.

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Calves
Inject subcutaneously as a single dose in the neck at a dosage of 2.5 mg/kg (1 mL/22 lb) body weight (BW). Do not inject more than 11.5 mL per injection site.

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The use of TULISSIN 25 Injectable Solution is contraindicated in animals previously found to be hypersensitive to the drug.

RESIDUE WARNINGS

Swine
Swine intended for human consumption must not be slaughtered within 5 days from the last treatment.

Calves
Calves intended for human consumption must not be slaughtered within 22 days from the last treatment with TULISSIN 25 Injectable Solution. This drug is not for use in ruminating cattle.

PRECAUTIONS

Swine
The effects of Tulissin 25 Injectable Solution on porcine reproductive performance, pregnancy, and lactation have not been determined. Intramuscular injection can cause a transient local tissue reaction that may result in trim loss of edible tissue at slaughter.
Cattle
The effects of Tulissin 25 Injectable Solution on bovine reproductive performance, pregnancy, and lactation have not been determined. Subcutaneous injection can cause a transient local tissue reaction that may result in trim loss of edible tissue at slaughter

Swine
In one field study, one out of 40 pigs treated with tulathromycin injection (100 mg/mL) at 2.5 mg/kg BW exhibited
mild salivation that resolved in less than four hours.

Calves
In one BRD field study, two calves treated with tulathromycin injection (100 mg/mL) at 2.5 mg/kg BW exhibited
transient hypersalivation. One of these calves also exhibited transient dyspnea, which may have been related to
pneumonia.

Post Approval Experience
The following adverse events are based on post approval adverse drug experience reporting for tulathromycin injection (100 mg/mL). Not all adverse events are reported to the FDA CVM. It is not always possible to reliably estimate the adverse event frequency or establish a causal relationship to product exposure using these data. The following adverse events are listed in decreasing order of reporting frequency in cattle: Injection site reactions and anaphylaxis/anaphylactoid reactions. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or www.fda.gov/reportanimalae.

At physiological pH, tulathromycin (a weak base) is approximately 50 times more soluble in hydrophilic than
lipophilic media. This solubility profile is consistent with the extracellular pathogen activity typically associated
with the macrolides.¹ Markedly higher tulathromycin concentrations are observed in the lung parenchyma as
compared to the plasma, and these elevated concentrations can remain in lung tissue for several days beyond
that which can be measured in the plasma. However the clinical relevance of these elevated lung concentrations is
undetermined.

As a class, macrolides tend to be primarily bacteriostatic, but may be bactericidal against some pathogens.²
When acting as a cidal compound, they tend to exhibit concentration independent killing; the rate of bacterial
eradication does not change once serum drug concentrations reach 2 to 3 times the minimum inhibitory
concentration (MIC) of the targeted pathogen. Under these conditions, the time that serum concentrations remain
above the MIC becomes the major determinant of antimicrobial activity. Macrolides also exhibit a post-antibiotic
effect (PAE), the duration of which tends to be both drug and pathogen dependent. In general, by increasing the
macrolide concentration and the exposure time, the PAE will increase to some maximal duration. ³ Tulathromycin
is eliminated from the body primarily unchanged via biliary excretion.

¹Carbon, C. 1998. Pharmacodynamics of Macrolides, Azalides, and Streptogramins: Effect on Extracellular
Pathogens. Clin. Infect. Dis., 27:28-32.

²Nightingale, C.J. 1997. Pharmacokinetics and Pharmacodynamics of Newer Macrolides. Pediatr. Infect. Dis. J.,
16:438-443.

³Andes D, Anon J, Jacobs MR, Craig WA. (2004). Application of pharmacokinetics and pharmacodynamics to
antimicrobial therapy of respiratory tract infections. Clin Lab Med., 24:477-502.

Swine
Following intramuscular (IM) administration to feeder pigs at a dosage of 2.5 mg/kg BW, tulathromycin is nearly
completely absorbed, with peak plasma concentrations achieved within ~0.25 hr. The volume of distribution
exceeds 15 L/kg, which is consistent with extensive tissue binding. This large distribution volume results in a long
terminal elimination half-life (60 to 90 hours) despite a rapid systemic free drug clearance (187 mL/kg/hr). There are
no gender differences in swine tulathromycin pharmacokinetics.

Comparative Bioavailability Summary
Despite slightly lower peak concentrations with tulathromycin injection 25 mg/mL, a single IM dose of 2.5 mg
tulathromycin/kg BW of either tulathromycin injection (100 mg/mL) or tulathromycin injection (25 mg/mL)
resulted in comparable tulathromycin total systemic exposure. Therefore, tulathromycin injection 25 mg/mL is
considered to be therapeutically equivalent to tulathromycin injection 100 mg/mL when administered to swine by
IM injection at a dose of 2.5 mg tulathromycin/kg BW.

Calves
Following subcutaneous (SC) administration into the neck of feeder calves at a dosage of 2.5 mg/kg BW,
tulathromycin is nearly completely absorbed, with peak plasma concentrations achieved within ~0.25 hr. The
volume of distribution exceeds 11 L/kg4, which is consistent with extensive tissue binding. This large distribution
volume results in a long terminal elimination half-life of more than 100 hours, despite a rapid systemic free drug
clearance (170 mL/kg/hr). No pharmacokinetic differences are observed in castrated male versus female calves.

Comparative Bioavailability Summary
Despite lower peak concentrations with tulathromycin injection 25 mg/mL, a single SC dose of 2.5 mg
tulathromycin/kg BW of either tulathromycin injection (100 mg/mL) or tulathromycin injection (25 mg/mL)
resulted in comparable total systemic tulathromycin exposure. Therefore, tulathromycin injection 25 mg/mL is
considered to be therapeutically equivalent to tulathromycin injection 100 mg/mL when administered to calves by
SC injection at a dose of 2.5 mg tulathromycin/kg BW.
4 Clearance and volume estimates are based on intersubject comparisons of 2.5 mg/kg BW administered by either
subcutaneous or intravenous injection

Swine
Tulathromycin has demonstrated in vitro activity against A. pleuropneumoniae, P. multocida, B. bronchiseptica, H. parasuis, and M. hyopneumoniae. The MICs of tulathromycin against indicated pathogens collected from field studies were determined using methods recommended by the Clinical and Laboratory Standards Institute (CLSI, M31-A and M31-A3). MICs for H. parasuis were determined using Veterinary Fastidious Medium and were incubated up to 48 hours at 35 to 37°C in a CO2-enriched atmosphere. These values are represented in Table 3, below.

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Calves
Tulathromycin has demonstrated in vitro activity against M. haemolytica, P. multocida, H. somni, and M. bovis, four pathogens associated with BRD. The MICs of tulathromycin against indicated pathogens collected from field studies using tulathromycin injection (100 mg/mL) were determined using methods recommended by the CLSI (M31-A2). These values are represented in Table 4, below.

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Swine
Plasma concentrations of tulathromycin administered as tulathromycin injection (100 mg/mL) or as tulathromycin injection 25 mg/mL were demonstrated to be therapeutically equivalent (see CLINICAL PHARMACOLOGY, Comparative Bioavailability Summary). Therefore, effectiveness studies conducted with tulathromycin injection (100 mg/mL) support the effectiveness for tulathromycin injection 25 mg/mL.

In a multi-location field study to evaluate the treatment of naturally occurring SRD, 266 pigs were treated with tulathromycin injection (100 mg/mL). Responses to treatment were compared to saline-treated controls. Success was defined as a pig with normal attitude, normal respiration, and rectal temperature of < 104°F on Day 7. The treatment success rate was significantly greater (P ≤ 0.05) in tulathromycin injection 100 mg/mL-treated pigs (70.5%) compared to saline-treated pigs (46.1%). M. hyopneumoniae was isolated from 106 saline-treated and non-treated sentinel pigs in this study.

Two induced infection model studies were conducted to confirm the effectiveness of tulathromycin injection (100 mg/mL) against M. hyopneumoniae. Ten days after inoculation intranasally and intratracheally with a field strain of M. hyopneumoniae, 144 pigs were treated with either tulathromycin injection 100 mg/mL (2.5 mg/kg BW) intramuscularly or an equivalent volume of saline. Pigs were euthanized and necropsied 10 days post-treatment. The mean percentage of gross pneumonic lung lesions was statistically significantly lower (P < 0.0001) for tulathromycin injection 100 mg/mL-treated pigs than for saline-treated pigs in both studies (8.52% vs. 23.62% and 11.31% vs. 26.42%).

The effectiveness of tulathromycin injection (100 mg/mL) for the control of SRD was evaluated in a multi-location natural infection field study. When at least 15% of the study candidates showed clinical signs of SRD, all pigs were enrolled and treated with tulathromycin injection 100 mg/mL (226 pigs) or saline (227 pigs). Responses to treatment were evaluated on Day 7. Success was defined as a pig with normal attitude, normal respiration, and rectal temperature of < 104°F. The treatment success rate was significantly greater (P < 0.05) in tulathromycin injection 100 mg/mL-treated pigs compared to saline-treated pigs (59.2% vs. 41.2%).

Calves
Plasma concentrations of tulathromycin administered as tulathromycin injection (100 mg/mL) or as tulathromycin injection 25 mg/mL were demonstrated to be therapeutically equivalent (see CLINICAL PHARMACOLOGY, Comparative Bioavailability Summary). Therefore, effectiveness studies conducted with tulathromycin injection (100 mg/mL) support the effectiveness for tulathromycin injection 25 mg/mL.

BRD - In a multi-location field study, 314 calves with naturally occurring BRD were treated with tulathromycin injection (100 mg/mL). Responses to treatment were compared to saline-treated controls. A cure was defined as a calf with normal attitude/activity, normal respiration, and a rectal temperature of ≤ 104°F on Day 14. The cure rate was significantly higher (P ≤ 0.05) in tulathromycin injection 100 mg/mL-treated calves (78%) compared to saline-treated calves (24%). There were two BRD-related deaths in the tulathromycin injection 100 mg/mL-treated calves compared to nine BRD-related deaths in the saline-treated calves.

Fifty-two tulathromycin injection (100 mg/mL)-treated calves and 27 saline-treated calves from the multi-location field BRD treatment study had Mycoplasma bovis identified in cultures from pre-treatment nasopharyngeal swabs. Of the 52 tulathromycin injection 100 mg/mL-treated calves, 37 (71.2%) calves were categorized as cures and 15 (28.8%) calves were categorized as treatment failures. Of the 27 saline-treated calves, 4 (14.8%) calves were categorized as cures and 23 (85.2%) calves were treatment failures.

A Bayesian meta-analysis was conducted to compare the BRD treatment success rate in young calves (calves weighing 250 lbs or less and fed primarily a milk-based diet) treated with tulathromycin injection (100 mg/mL) to the success rate in older calves (calves weighing more than 250 lbs and fed primarily a roughage and grain-based diet) treated with tulathromycin injection 100 mg/mL. The analysis included data from four BRD treatment effectiveness studies conducted for the approval of tulathromycin injection (100 mg/mL) in the U.S. and nine contemporaneous studies conducted in Europe. The analysis showed that the BRD treatment success rate in young calves was at least as good as the BRD treatment success rate in older calves. As a result, tulathromycin injection (100 mg/mL) was considered effective for the treatment of BRD associated with M. haemolytica, P. multocida, H. somni, and M. bovis in suckling calves, dairy calves, and veal calves.

Two induced infection model studies were conducted to confirm the effectiveness of tulathromycin injection (100 mg/mL) against Mycoplasma bovis. A total of 166 calves were inoculated intratracheally with field strains of Mycoplasma bovis. When calves became pyrexic and had abnormal respiration scores, they were treated with either tulathromycin injection 100 mg/mL (2.5 mg/kg BW) subcutaneously or an equivalent volume of saline. Calves were observed for signs of BRD for 14 days post-treatment, then were euthanized and necropsied. In both studies, mean lung lesion percentages were statistically significantly lower in the tulathromycin injection 100 mg/mL-treated calves compared with saline-treated calves (11.3% vs. 28.9%, P = 0.0001 and 15.0% vs. 30.7%, P < 0.0001).

Swine

Plasma concentrations of tulathromycin administered as tulathromycin injection (100 mg/mL) or as tulathromycin injection 25 mg/mL were demonstrated to be therapeutically equivalent (see CLINICAL PHARMACOLOGY, Comparative Bioavailability Summary). Therefore, systemic target animal safety studies conducted with tulathromycin injection 100 mg/mL support the systemic safety for tulathromycin injection 25 mg/mL.

Safety studies were conducted in pigs receiving a single intramuscular dose of 25 mg/kg BW, or 3 weekly intramuscular doses of 2.5, 7.5, or 12.5 mg/kg BW (both studies utilized tulathromycin injection (100 mg/mL)). In all groups, transient indications of pain after injection were seen, including restlessness and excessive vocalization. Tremors occurred briefly in one animal receiving 7.5 mg/kg BW. Discoloration and edema of injection site tissues and corresponding histopathologic changes were seen in animals at all dosages and resolved over time. No other drug-related lesions were observed macroscopically or microscopically.

Sixteen growing pigs were injected with either saline or tulathromycin injection 25 mg/mL as a single injection of 4 mL. Injection site observations included two instances of erythema in the tulathromycin injection 25 mg/mL-treated group on Day 1 post-injection. No heat, sensitivity, firmness, necrosis, drainage, or swelling was observed at any injection sites in either treatment group. The gross and microscopic findings in the tulathromycin injection 25 mg/mL-treated group were consistent with inflammatory changes induced by injections and were considered to be mild or moderate with progression to macroscopic resolution by Day 28 post-injection and microscopic resolution by Day 42 post-injection.

Calves

Plasma concentrations of tulathromycin administered as tulathromycin injection (100 mg/mL) or as tulathromycin injection 25 mg/mL were demonstrated to be therapeutically equivalent (see CLINICAL PHARMACOLOGY, Comparative Bioavailability Summary). Therefore, systemic target animal safety studies conducted with tulathromycin injection 100 mg/mL support the systemic safety for tulathromycin injection 25 mg/mL.

A safety study was conducted in feeder calves receiving tulathromycin injection (100 mg/mL) as a single subcutaneous dose of 25 mg/kg BW, or 3 weekly subcutaneous doses of 2.5, 7.5, or 12.5 mg/kg BW. In all groups, transient indications of pain after injection were seen, including head shaking and pawing at the ground. Injection site swelling, discoloration of the subcutaneous tissues at the injection site and corresponding histopathologic changes were seen in animals in all dosage groups. These lesions showed signs of resolving over time. No other drug-related lesions were observed macroscopically or microscopically.

An exploratory study was conducted in feeder calves receiving tulathromycin injection (100 mg/mL) as a single subcutaneous dose of 10, 12.5, or 15 mg/kg BW. Macroscopically, no lesions were observed. Microscopically, minimal to mild myocardial degeneration was seen in one of six calves administered 12.5 mg/kg BW and two of six calves administered
15 mg/kg BW.

A safety study was conducted in preruminant calves 13 to 27 days of age receiving tulathromycin injection (100 mg/mL) at 2.5 mg/kg BW or 7.5 mg/kg BW once subcutaneously. With the exception of minimal to mild injection site reactions, no drug-related clinical signs or other lesions were observed macroscopically or microscopically.

Sixteen growing cattle were injected with either saline (eight animals) as a single injection of 11.5 mL or tulathromycin injection 25 mg/mL (eight animals) as a single injection of either 2.5 mg/kg BW or a dose volume of 11.5 mL (whichever volume was higher). One calf in the tulathromycin injection 25 mg/mL-treated group was observed to have firmness atthe injection site for a single day. Two tulathromycin injection 25 mg/mL-treated calves exhibited injection site swelling. In one calf, the swelling resolved within 48 hours. In the other calf, the swelling was observed over a three-day period, after which the calf underwent a scheduled necropsy, preventing further injection site observations. No injection site swelling was observed in saline-treated animals. At necropsy, three of the saline-treated calves and five of the tulathromycin injection 25 mg/mL-treated calves had altered tissue present at the injection site. The gross and microscopic findings in the tulathromycin injection 25 mg/mL-treated group were consistent with inflammatory changes induced by injections, were considered to be mild to marked, and progressed to macroscopic resolution and microscopic resolution by Day 42 post-injection.

Store at or below 30°C (86°F). Use within 45 days of first puncture and puncture a maximum of 30 times. Consider using automatic injection equipment or a repeater syringe. When using a needle or draw-off spike larger than 16 gauge, discard any remaining product immediately after use.

TULISSIN 25 (tulathromycin injection) Injectable Solution is available in the following package sizes:
50 mL vial
100 mL vial
250 mL vial

Manufactured for:
Virbac AH, Inc.
P.O. Box 162059, Fort Worth, TX 76161
Made in France

Approved by FDA under ANADA # 200-668

To report suspected adverse drug events, for technical assistance or to obtain a copy of the Safety Data Sheet (SDS), contact Virbac AH, Inc. at 1-800-338-3659 or us.virbac.com. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or www.fda.gov/reportanimalae.

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TULISSIN is a registered trademark of Virbac S.A.

Rev. 06/21

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