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Loncor 300

This page contains information on Loncor 300 for veterinary use.
The information provided typically includes the following:
  • Loncor 300 Indications
  • Warnings and cautions for Loncor 300
  • Direction and dosage information for Loncor 300

Loncor 300

This treatment applies to the following species:
Company: Elanco US

(florfenicol)

300 mg/mL Injectable Solution

For intramuscular and subcutaneous use in beef and non-lactating dairy cattle only

Not for use in female dairy cattle 20 months of age or older or in calves to be processed for veal

Loncor 300 Caution

Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Description

LONCOR™ 300 Injectable Solution is a solution of the synthetic antibiotic florfenicol. Each milliliter of sterile LONCOR™ 300 contains 300 mg of florfenicol, 250 mg N-Methyl-2-pyrrolidone, 150 mg propylene glycol, and polyethylene glycol qs.

Loncor 300 Indications

LONCOR™ 300 is indicated for treatment of bovine respiratory disease (BRD) associated with Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni, and for the treatment of bovine interdigital phlegmon (foot rot, acute interdigital necrobacillosis, infectious pododermatitis) associated with Fusobacterium necrophorum and Bacteroides melaninogenicus. Also, it is indicated for the control of respiratory disease in cattle at high risk of developing BRD associated with Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni.

Loncor 300 Dosage And Administration

For treatment of bovine respiratory disease (BRD) and bovine interdigital phlegmon (foot rot): LONCOR™ 300 should be administered by intramuscular injection to cattle at a dose rate of 20 mg/kg body weight (3 mL/100 lbs). A second dose should be administered 48 hours later. Alternatively, LONCOR™ 300 can be administered by a single subcutaneous (SC) injection to cattle at a dose rate of 40 mg/kg body weight (6 mL/100 lbs). Do not administer more than 10 mL at each site. The injection should be given only in the neck.

NOTE: Intramuscular injection may result in local tissue reaction which persists beyond 28 days. This may result in trim loss of edible tissue at slaughter. Tissue reaction at injection sites other than the neck is likely to be more severe.

For control of respiratory disease in cattle at high risk of developing BRD: LONCOR™ 300 should be administered by a single subcutaneous injection to cattle at a dose rate of 40 mg/kg body weight (6 mL/100 lbs). Do not administer more than 10 mL at each site. The injection should be given only in the neck.

LONCOR™ 300 DOSAGE GUIDE

ANIMAL WEIGHT
(lbs)

IM LONCOR 300 DOSAGE
3.0 mL/100 lb Body Weight (mL)

SC LONCOR 300 DOSAGE
6.0 mL/100 lb Body Weight (mL)

100

3.0

6.0

200

6.0

12.0

300

9.0

18.0

400

12.0

24.0

500

15.0

30.0

600

18.0

36.0

700

21.0

42.0

800

24.0

48.0

900

27.0

54.0

1000

30.0

60.0

RECOMMENDED INJECTION LOCATION

Clinical improvement should be evident in most treated subjects within 24 hours of initiation of treatment. If a positive response is not noted within 72 hours of initiation of treatment, the diagnosis should be re-evaluated.

Contraindications

Do not use in animals that have shown hypersensitivity to florfenicol.

WARNINGS: NOT FOR HUMAN USE. KEEP OUT OF REACH OF CHILDREN.

This product contains materials that can be irritating to skin and eyes. Avoid direct contact with skin, eyes, and clothing. In case of accidental eye exposure, flush with water for 15 minutes. In case of accidental skin exposure, wash with soap and water. Remove contaminated clothing. Consult a physician if irritation persists. Accidental injection of this product may cause local irritation. Consult a physician immediately. The Safety Data Sheet (SDS) contains more detailed occupational safety information. For customer service, adverse effects reporting, and/or a copy of the SDS, call 1-800-422-9874.

Precautions

Not for use in animals intended for breeding purposes. The effects of florfenicol on bovine reproductive performance, pregnancy, and lactation have not been determined. Toxicity studies in dogs, rats, and mice have associated the use of florfenicol with testicular degeneration and atrophy. Intramuscular injection may result in local tissue reaction which persists beyond 28 days. This may result in trim loss of edible tissue at slaughter. Tissue reaction at injection sites other than the neck is likely to be more severe.

Residue Warnings

Animals intended for human consumption must not be slaughtered within 28 days of the last intramuscular treatment. Animals intended for human consumption must not be slaughtered within 38 days of subcutaneous treatment. This product is not approved for use in female dairy cattle 20 months of age or older, including dry dairy cows. Use in these cattle may cause drug residues in milk and/or calves born to these cows. A withdrawal period has not been established in pre-ruminating calves. Do not use in calves to be processed for veal.

Adverse Reactions

Inappetence, decreased water consumption, or diarrhea may occur transiently following treatment.

To report suspected adverse drug events, for technical assistance or to obtain a copy of the Safety Data Sheet (SDS), contact Elanco at 1-800-422-9874. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or http://www.fda.gov/reportanimalae.

Clinical Pharmacology

The pharmacokinetic disposition of florfenicol was evaluated in feeder calves following single intramuscular (IM) administration at the recommended dose of 20 mg/kg body weight. Florfenicol was also administered intravenously (IV) to the same cattle in order to calculate the volume of distribution, clearance, and percent bioavailability1 (Table 1).

TABLE 1. Pharmacokinetic Parameter Values for Florfenicol Following IM Administration of 20 mg/kg Body Weight to Feeder Calves (n=10).

Parameter

Median

Range

Cmax (µg/mL)

3.07*

1.43 - 5.60

Tmax (hr)

3.33

0.75 - 8.00

T 1/2 (hr)

18.3**

8.30 - 44.0

AUC (µg•min/mL)

4242

3200 - 6250

Bioavailability (%)

78.5

59.3 - 106

Vdss (L/kg)***

0.77

0.68 - 0.85

Clt (mL/min/kg)***

3.75

3.17 - 4.31

* harmonic mean

** mean value

*** following IV administration

Cmax Maximum serum concentration

Tmax Time at which Cmax is observed

T 1/2 Biological half-life

AUC Area under the curve

Vdss Volume of distribution at steady state

Clt Total body clearance

Florfenicol was detectable in the serum of most animals through 60 hours after intramuscular administration with a mean concentration of 0.19 µg/mL. The protein binding of florfenicol was 12.7%, 13.2%, and 18.3% at serum concentrations of 0.5, 3.0, and 16.0 µg/mL, respectively.

Microbiology

Florfenicol is a synthetic, broad-spectrum antibiotic active against many Gram-negative and Gram-positive bacteria isolated from domestic animals. It acts by binding to the 50S ribosomal subunit and inhibiting bacterial protein synthesis. Florfenicol is generally considered a bacteriostatic drug, but exhibits bactericidal activity against certain bacterial species. In vitro studies demonstrate that florfenicol is active against the bovine respiratory disease (BRD) pathogens Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni, and that florfenicol exhibits bactericidal activity against strains of M. haemolytica and H. somni. Clinical studies confirm the efficacy of florfenicol against BRD as well as against commonly isolated bacterial pathogens in bovine interdigital phlegmon including Fusobacterium necrophorum and Bacteroides melaninogenicus.

The minimum inhibitory concentrations (MICs) of florfenicol for BRD organisms were determined using isolates obtained from natural infections from 1990 to 1993. The MICs for interdigital phlegmon organisms were determined using isolates obtained from natural infections from 1973 to 1997 (Table 2).

TABLE 2. Florfenicol Minimum Inhibitory Concentration (MIC) Values* of Indicated Pathogens Isolated From Natural Infections of Cattle.

Indicated pathogens

Year of isolation

Isolate Numbers

MIC50**
(µg/mL)

MIC90**
(µg/mL)

Mannheimia haemolytica

1990 to 1993

398

0.5

1

Pasteurella multocida

1990 to 1993

350

0.5

0.5

Histophilus somni

1990 to 1993

66

0.25

0.5

Fusobacterium necrophorum

1973 to 1997

33

0.25

0.25

Bacteroides melaninogenicus

1973 to 1997

20

0.25

0.25

* The correlation between the in vitro susceptibility data and clinical effectiveness is unknown.

** The lowest MIC to encompass 50% and 90% of the most susceptible isolates, respectively.

Animal Safety

A 10X safety study was conducted in feeder calves. Two intramuscular injections of 200 mg/kg were administered at a 48-hour interval. The calves were monitored for 14 days after the second dose. Marked anorexia, decreased water consumption, decreased body weight, and increased serum enzymes were observed following dose administration. These effects resolved by the end of the study.

A 1X, 3X, and 5X (20, 60, and 100 mg/kg) safety study was conducted in feeder calves for 3X the duration of treatment (6 injections at 48-hour intervals). Slight decrease in feed and water consumption was observed in the 1X dose group. Decreased feed and water consumption, body weight, urine pH, and increased serum enzymes, were observed in the 3X and 5X dose groups. Depression, soft stool consistency, and dehydration were also observed in some animals (most frequently at the 3X and 5X dose levels), primarily near the end of dosing.

A 43-day controlled study was conducted in healthy cattle to evaluate effects of florfenicol administered at the recommended dose on feed consumption. Although a transient decrease in feed consumption was observed, florfenicol administration had no long-term effect on body weight, rate of gain, or feed consumption.

Storage Information

Store below 30°C (86°F).

Once opened, use contents within 6 months.

The solution is light yellow to straw colored. Color does not affect potency.

HOW SUPPLIED

Loncor™ 300 is packaged in 250 mL and 500 mL glass sterile multiple-dose vials.

REFERENCE

1. Lobell RD, Varma KJ, et al. Pharmacokinetics of florfenicol following intravenous and intramuscular doses to cattle. J Vet Pharmacol Therap. 1994; 17:253-258.

Made in China

LV2102

© 2021 Elanco or its affiliates.

Approved by FDA under ANADA # 200-582

February, 2021

LONCOR™ 300

LONCOR, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates.

Elanco US Inc, Shawnee, KS 66216 U.S.A.

Regulations for product use are established by country. Information contained on this site pertains only to the United States of America, and is not intended to provide adequate information for product use. Before using or dispensing any product, read and carefully observe the label directions.

BAYER HEALTHCARE LLC
Distributed by ELANCO US, INC.
2500 INNOVATION WAY, GREENFIELD, IN, 46140
Customer Service:   317-276-1262
Technical Service:   800-428-4441
Website:   www.elanco.us
Email:   elanco@elanco.com
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