Tetracyclines

The tetracyclines are broad-spectrum antibacterials active against Mycoplasma, Chlamydophila, and Rickettsia in addition to bacteria. They are active against a range of Gram-positive and Gram-negative bacteria but have little useful activity against E. coli, Salmonella, Proteus, or Pseudomonas spp. Tetracyclines are bacteriostatic and acquired resistance is now widespread among bacteria.

The widely used oxytetracycline and the less often used tetracycline and chlortetracycline have similar properties. When given by intramuscular injection they may be irritant, depending on the vehicle used. For this reason some preparations incorporate a local anaesthetic, which reduces the pain (temporarily), but not the tissue damage. Depot preparations will maintain effective plasma concentrations for 72 to 96 hours. Some preparations may be given intravenously, but rapid injection by this route in cattle may cause cardiovascular collapse, apparently due to chelation of calcium. Oral administration may cause diarrhoea. Absorption of tetracyclines from the gastro-intestinal tract is variable and is reduced by milk (not doxycycline), antacids, and calcium, iron, magnesium, and zinc salts.

Tetracyclines are deposited in developing teeth by binding to calcium and if given to puppies, kittens, or bitches or queens in late pregnancy they may cause discoloration and defects of the enamel of the puppies’ temporary dentition. Horses that are given parenteral or enteral tetracyclines and also exposed to stress may suffer a severe enterocolitis, which can prove fatal. Photodermatitis has occurred following treatment with tetracyclines after exposure to intense sunlight or ultraviolet light. There are reports of nephrotox-icity being associated with use of tetracyclines. These may have been due to degradation products which accumulate in preparations which are used beyond the expiry date. The main excretory routes for tetracyclines are the urinary system and the gastro-intestinal tract via the biliary system. Doxycycline and minocycline are more lipophilic than the older tetracyclines and have a number of advantages. Absorption of orally administered doxycycline and minocycline is better and they are less affected by milk and calcium salts. These drugs also penetrate better into several body compartments and fluids, notably bronchial secretions and prostatic fluid. Doxycycline enters the gastro-intestinal tract through the bile and is particularly liable to produce enterocolitis in the horse. Minocycline is metabolised prior to excretion in the bile. These lipid soluble tetracyclines are safer to use in animals with renal impairment. Tetracyclines, particularly doxycycline, are used for the treatment of canine ehrlichiosis caused by rickettsial organisms within the genera, Ehrlichia and Anaplasma. The cause of canine monocytic ehrlichiosis is E. canis, which is transmitted by the tick Rhipicephalus sanguineus. Granulo-cytic ehrlichiosis or tick-borne fever of sheep is caused by A. phagocytophilum. It infects dogs and is transmitted by the tick Ixodes ricinus.

CHLORTETRACYCLINE

Indications. Chlortetracycline-sensitive infections; theileriosis

Contra-indications. Oral administration to ruminants with a functional rumen is not recommended; renal impairment; last 2-3 weeks of gestation in pregnant animals and up to 4 weeks of age in neonates, see notes above; avoid use in patients with dysphagia or diseases accompanied by vomiting

Side-effects. May cause vomiting, diarrhoea

Dose: Dosages vary For guidance. By mouth.

Calves: 10-20 mg/kg body-weight daily

Pigs: 10-20 mg/kg body-weight daily by addition to feed, 400-600 g/tonne feed

Chickens: 20-50 mg/kg body-weight by addition to feed, 300-400 g/tonne feed

Turkeys, ducks: 10-30 mg/kg body-weight; 300-400 g/ tonne feed

Prescription-only medicine: Aureomycin Soluble Oblets (Fort Dodge) UK

Tablets, or to prepare an oral solution, scored, chlortetracycline hydrochloride 500 mg, for calves

Withdrawal Periods.

Calves: slaughter 25 days

Prescription-only medicine: Aureomycin Soluble Powder (Fort Dodge) UK

Oral powder, for addition to drinking water or to prepare an oral solution, chlortetracycline hydrochloride 55 g/kg, for calves, pigs, chickens, turkeys

Withdrawal Periods.

Calves: slaughter 25 days.

Pigs: slaughter 10 days.

Chickens, turkeys: slaughter 1 day, egg withdrawal period nil

Medicated feedingstuff prescription: Aurofac 100 Granular (Alpharma) UK

Premix, chlortetracycline hydrochloride 100 g/kg, for pigs, chickens, turkeys, ducks

Withdrawal Periods.

Pigs: slaughter 10 days.

Chickens, turkeys: slaughter 2 days, egg withdrawal period nil.

Ducks: slaughter 4 days

Prescription-only medicine: Aurofac 200 MA (Fort Dodge) UK

Oral powder, for addition to milk, milk replacer, or to prepare an oral solution, chlortetracycline hydrochloride 200 g/kg, for calves

Withdrawal Periods.

Calves: slaughter 15 days

Medicated feedingstuff prescription: Aurogran (Novartis) UK

Premix, chlortetracycline 100 g/kg, for pigs, chickens, turkeys

Withdrawal Periods.

Pigs: slaughter 14 days.

Chickens: slaughter 6 days, eggs 6 days.

Turkeys: slaughter 3 days

Medicated feedingstuff prescription: Aurogran 150 (Novartis) UK

Premix, chlortetracycline 150 g/kg, for pigs, chickens, turkeys

Withdrawal Periods.

Pigs: slaughter 14 days.

Chickens: slaughter 6 days, eggs 6 days.

Turkeys: slaughter 3 days

Prescription-only medicine: Chlorsol 50 (Vetoquinol) UK

Oral powder, for addition to drinking water, chlortetracycline hydrochloride 500 g/kg, for pigs, broiler chickens

Withdrawal Periods.

Pigs: slaughter 6 days.

Chickens: slaughter 3 days

Contra-indications. Pregnant sows; laying hens

Medicated feedingstuff prescription: Chlortet FG 100 (ECO) UK

Premix, chlortetracycline 100 g/kg, for pigs

Withdrawal Periods.

Pigs: slaughter 7 days

DOXYCYCLINE

Indications. Doxycycline-sensitive infections, in particular respiratory tract infections; ehrlichiosis

Contra-indications. Hepatic impairment; pregnant animals; up to 4 weeks of age in neonates, see notes above; avoid use in patients with dysphagia or diseases accompanied by vomiting

Side-effects. Vomiting, oesophagitis, diarrhoea, photodermatitis; hepatic damage and oesophageal ulcers with long-term treatment

Warnings. Avoid use during reproductive period of birds; manufacturer advises that birds do not participate in races during treatment; deionised or distilled water should be used; mineral salts, citric acid, ferrous products can affect absorption; Drug Interactions – see tetracyclines; use during period of tooth development may lead to tooth discoloration (less risk than other tetracyclines)

Dose:

Dogs: by mouth, 10 mg/kg daily, given with food

Cats: by mouth, 10 mg/kg daily

Feline chlamydophilial infections, by mouth, 5 mg/kg 1-2 times daily

Pigeons, caged birds: by addition to drinking water, 15 mg/ kg or 260 mg/2 litres drinking water. For birds with low daily water intake, 260 mg/500 mL drinking water

Prescription-only medicine: Doxirobe (Pfizer) UK

See section 3.11 for preparation details

Prescription-only medicine: Doxyseptin (Vetoquinol) UK

Tablets, doxyxcycline (as hyclate) 300 mg, for dogs more than 15 kg body-weight

Prescription-only medicine: Ornicure (Genitrix) UK

Oral powder, for addition to drinking water, doxycycline (as hyclate) 260 mg/sachet, for pigeons, cage birds

Prescription-only medicine: Ronaxan (Merial) UK

Tablets, doxycycline 20 mg, for dogs, cats

Tablets, doxycycline 100 mg, for dogs

OXYTETRACYCLINE

Indications. Oxytetracycline-sensitive infections; theileriosis

Contra-indications. Oral administration to ruminants with a functional rumen; renal impairment; last 2-3 weeks of gestation in pregnant animals and up to 4 weeks of age in neonates, see notes above; avoid use in patients with dysphagia or diseases accompanied by vomiting; avoid subcutaneous injection or concurrent corticosteroids in horses; some manufacturers recommend that intravenous injection in dogs should be avoided

Side-effects. May cause vomiting, diarrhoea; photodermatitis; transient swelling at site of injection

Warnings. Care with use in animals with renal or hepatic impairment; Drug Interactions

Dose: Dosages vary. For guidance.

Horses: by intramuscular or intravenous injection, 2-10 mg/kg daily

Cattle, sheep, goats, pigs: by intramuscular or intravenous injection, 2-10 mg/kg daily

by depot intramuscular injection, 20 mg/kg, repeat after 2-4 days or

30 mg/kg (preparations containing oxytetracycline 300 mg/ mL), repeat after 6 days

calves, pigs: by mouth, dosage varies, for guidance 10-30 mg/kg 1-2 times daily but see also manufacturer’s information

Red deer: by depot intramuscular injection, 20 mg/kg, repeat after 2-4 days

Dogs: by mouth, 25 mg/kg twice daily by subcutaneous or intramuscular injection, 2-10 mg/kg daily

Cats: by subcutaneous or intramuscular injection, 2-10 mg/kg daily

Poultry: by addition to drinking water, 7-27 g/100 litres

Cage birds: see preparation details

Fish: see Prescribing for fish for preparation details and dosage

Prescription-only medicine: Alamycin 10 (Norbrook) UK

Injection, oxytetracycline hydrochloride 100 mg/mL, for cattle, pigs;

Withdrawal Periods.

Cattle: slaughter 15 days, milk 2.5 days.

Pigs: slaughter 15 days

Prescription-only medicine: Alamycin LA (Norbook) UK

Depot injection, oxytetracycline dihydrate 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 31 days, milk 10 days.

Sheep: slaughter 9 days, milk 7 days.

Pigs: slaughter 18 days

Prescription-only medicine: Alamycin LA 300 (Norbrook) UK

Depot injection, oxytetracycline (as dihydrate) 300 mg/mL, for cattle, sheep, pigs

Withdrawal Periods. (20 mg/kg dose)

Cattle: slaughter 28 days, milk 10 days.

Sheep: slaughter 28 days, milk 8 days.

Pigs: slaughter 14 days. (30 mg/kg dose)

Cattle: slaughter 35 days, milk 10 days.

Sheep: slaughter 28 days, milk 8 days.

Pigs: slaughter 28 days

Prescription-only medicine: Duphacycline 100 (Fort Dodge) UK

Injection, oxytetracycline hydrochloride 100 mg/mL, for cattle, pigs

Withdrawal Periods.

Cattle: slaughter 15 days, milk 2.5 days.

Pigs: slaughter 15 days

Prescription-only medicine: Duphacycline LA (Fort Dodge) UK

Depot injection, oxytetracycline dihydrate 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 31 days, milk 10 days.

Sheep: slaughter 9 days.

Pigs: slaughter 18 days

Prescription-only medicine: Duphacycline XL (Fort Dodge) UK

Depot injection, oxytetracycline (as dihydrate) 300 mg/mL, for cattle, pigs

Withdrawal Periods. (20 mg/kg dose)

Cattle: slaughter 28 days, milk 10 days.

Pigs: slaughter 14 days. (30 mg/kg dose)

Cattle: slaughter 35 days, milk 10 days.

Pigs: slaughter 28 days

Prescription-only medicine: Engemycin LA (Intervet) UK

Depot injection, oxytetracycline 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 31 days, milk 10 days.

Sheep: slaughter 9 days, milk 7 days.

Pigs: slaughter 18 days

Prescription-only medicine: Engemycin 5% (Intervet) UK

Injection, oxytetracycline (as hydrochloride) 50 mg/mL, for horses, cattle, sheep, pigs, dogs, cats

Withdrawal Periods. Should not be used in horses intended for human consumption.

Cattle: slaughter 35 days, milk 6 days.

Sheep: slaughter 14 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 14 days

Prescription-only medicine: Engemycin 10% (DD) (Intervet) UK

Injection and depot injection, oxytetracycline (as hydrochloride) 100 mg/mL, for horses, cattle, sheep, pigs, dogs, cats

Withdrawal Periods. Should not be used in horses intended for human consumption.

Cattle: (daily dosage) slaughter 35 days, milk 6 days, (prolonged-action dosage) slaughter 21 days, milk 6 days.

Sheep: (daily dosage, prolonged-action dosage) slaughter 14 days, should not be used in sheep producing milk for human consumption.

Pigs: (daily dosage) slaughter 14 days, (prolonged-action dosage) slaughter 10 days

Prescription-only medicine: Engemycin 10% Farm Pack (Intervet) UK

Injection and depot injection, oxytetracycline (as hydrochloride) 100 mg/ mL, for horses, cattle, sheep, pigs, dogs, cats

Withdrawal Periods. Should not be used in horses intended for human consumption.

Cattle: (daily dosage) slaughter 35 days, milk 6 days, (prolonged-action dosage) slaughter 21 days, milk 6 days.

Sheep: (daily dosage, prolonged-action dosage) slaughter 14 days, should not be used in sheep producing milk for human consumption.

Pigs: (daily dosage) slaughter 14 days, (prolonged-action dosage) slaughter 10 days

Prescription-only medicine: Hexasol LA (Norbrook) UK

Injection, flunixin (as flunixin meglumine) 20 mg, oxytetracycline hydrochloride (as dihydrate) 300 mg/mL, for cattle

Withdrawal Periods.

Cattle: slaughter 35 days, should not be used in cattle producing milk for human consumption

Dose:

Cattle: by intramuscular injection, 0.1 mL/kg

Prescription-only medicine: Occrycetin Bolus (Fort Dodge) UK

Tablets, scored, oxytetracycline hydrochloride 500 mg, for calves

Withdrawal Periods.

Calves: slaughter 14 days

Prescription-only medicine: Ornimed Oxytetracycline (distributed by Millpledge) UK Medicated seed, oxytetracycline 3 mg/g, for budgerigars

Side-effects. May cause fungal infections and soft shelled eggs with prolonged treatment

Dose: Birds: 1.5 g of seed twice daily

Prescription-only medicine: Oxycare 10% (Animalcare) UK

Injection, oxytetracycline hydrochloride 50 mg/mL, for cattle, pigs

Withdrawal Periods.

Cattle: slaughter 15 days, milk 2.5 days.

Pigs: slaughter 15 days

Prescription-only medicine: Oxycare 20/LA (Animalcare) UK

Depot injection, oxytetracycline (as dihydrate) 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 14 days, milk 7 days.

Sheep: slaughter 14 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 14 days

Prescription-only medicine: Oxycare Tablets (Animalcare) UK

Tablets, s/c, oxytetracycline dihydrate 50 mg, 100 mg, 250 mg, for dogs

Prescription-only medicine: Oxycomplex NS (Bimeda) UK

Injection, oxytetracycline (as hydrochloride) 100 mg, flunixin (as meglumine) 20 mg/mL, for cattle

Withdrawal Periods.

Cattle: slaughter 31 days, should not be used in cattle producing milk for human consumption

Dose:

Cattle: initially by intravenous injection, then by intramuscular injection, 0.1 mL/kg daily for up to 5 days

Prescription-only medicine: Oxytetrin 5 (Schering-Plough) UK

Injection, oxytetracycline hydrochloride 50 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 7 days, milk 3 days.

Sheep: slaughter 5 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 11 days

Prescription-only medicine: Oxytetrin 10 DD (Schering-Plough) UK

Injection and depot injection in cattle, oxytetracycline hydrochloride 100 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 10 days, milk 80 hours.

Sheep: slaughter 5 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 11 days

Withdrawal Periods.

Cattle: slaughter 10 days, milk 80 hours

Prescription-only medicine: Oxytetrin 20 LA (Schering-Plough) UK

Depot injection, oxytetracycline dihydrate 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 14 days, milk 7 days.

Sheep: slaughter 21 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 35 days

Prescription-only medicine: Terramycin LA Injectable Solution (Pfizer)

Depot injection, oxytetracycline (as dihydrate) 200 mg/mL, for cattle, sheep, red deer, pigs

Withdrawal Periods.

Cattle: slaughter 21 days, milk 7 days.

Sheep: slaughter 21 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 21 days. Red deer: slaughter 30 days Note. Administered by intravenous injection in cattle for short-acting effect

Prescription-only medicine: Terramycin Q-100 Injectable Solution (Pfizer) UK

Injection, oxytetracycline hydrochloride (as magnesium complex) 100 mg/ mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 14 days, milk 5 days.

Sheep: slaughter 28 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 21 days

Prescription-only medicine: Terramycin Soluble Powder 5.5% (Pfizer) UK

Oral powder, for addition to drinking water or feed, or to prepare an oral solution, oxytetracycline hydrochloride 55 g/kg, for cattle, pigs, chickens, turkeys (measure provided = oxytetracycline 200 mg)

Withdrawal Periods.

Cattle: slaughter 10 days, milk withdrawal period nil.

Pigs: slaughter 7 days.

Chickens, turkeys: slaughter 7 days, eggs 1 day

Prescription-only medicine: Terramycin Soluble Powder Concentrate 20% (Pfizer) UK

Oral powder, for addition to drinking water or feed or to prepare an oral solution, oxytetracycline hydrochloride 200 g/kg, for cattle, pigs, chickens, turkeys (measure provided = oxytetracycline 1 g)

Withdrawal Periods.

Cattle: slaughter 10 days, milk withdrawal period nil.

Pigs: slaughter 7 days.

Chickens, turkeys: slaughter 7 days, eggs 1 day

Medicated feedingstuff prescription: Tetramin 200 (Pfizer) UK

Premix, oxytetracycline dihydrate 200 g/kg, for pigs 5-90 kg body-weight

Withdrawal Periods.

Pigs: slaughter 5 days

Prescription-only medicine: Tetroxy LA (Bimeda) UK

Depot injection, oxytetracycline (as magnesium complex) 200 mg/mL, for cattle, sheep, pigs

Withdrawal Periods.

Cattle: slaughter 14 days, milk 7 days.

Sheep: slaughter 21 days, should not be used in sheep producing milk for human consumption.

Pigs: slaughter 35 days

TETRACYCLINE HYDROCHLORIDE

Indications. Tetracycline-sensitive infections

Dose: By addition to drinking water.

Pigs: 40 mg/kg daily; 33 g/100 litres drinking water

Poultry: 60 mg/kg; 55 g/100 litres drinking water

Prescription-only medicine: Tetsol 800 (Novartis) UK

Oral powder, for addition to drinking water, tetracycline hydrochloride 800 g/kg, for pigs, chickens

Withdrawal Periods.

Pigs: slaughter 10 days.

Poultry: slaughter 3 days, should not be used in laying birds producing eggs for human consumption