KNOW ABOUT ONE DRUG EVERY DAY MELOXICAM

KNOW ABOUT ONE DRUG EVERY DAY

MELOXICAM

Type

• COX-2 receptor preferential NSAID in the oxicam class, with anti-inflammatory, analgesic and antipyretic activity.

Pharmacology & General Information

Pharmacology

• Anti-inflammatory, analgesic and antipyretic properties probably through the inhibition of cyclooxygenase, phospholipidase A₂ and inhibition of prostaglandin synthesis.
• Meloxicam is considered to be COX-2 preferential (not COX-2 specific) as at higher dosages its COX-2 specificity is diminished.

Therapeutic Information

Uses/Indications

Appropriate Use

• Inflammation and pain.
• An anti-inflammatory, analgesic and antipyretic agent.
• Principally used for the symptomatic treatment of osteoarthritis in dogs.
• Also has anti-exudative effects and reduces leucocyte infiltration into the inflamed tissue.

Pharmacokinetics and Drug Interactions

Absorption /Bioavailability

• Well absorbed in dogs after oral administration. Peak blood levels occur about 7-8 hours after administration.
• In rabbits: After a single oral dose of 0.3 or 1.5 mg/kg, maximal plasma concentrations of 0.14 μg/mL and 0.3 μg/mL, respectively occurred at six to eight hours.

Distribution

• In dogs, the volume of distribution is 0.3 l/kg.

Plasma Protein binding / Storage

• In the dog, about 97% is bound to plasma proteins.
• In cattle and pigs, more than 98% of meloxicam is bound to plasma proteins.
• The highest concentrations are found in the kidney and liver, with relatively low levels in skeletal muscle and fat.

Elimination Route

• "In all species studied, meloxicam undergoes extensive hepatic metabolism into 4 inactive metabolites that are excreted in both urine and feces."
• Extensively biotransformed to several different metabolites in the liver, none of which appear to have pharmacologic activity.
• The majority of the metabolites, and the unchanged drug, are eliminated in the faeces.
• A significant amount of enterohepatic recirculation occurs.
• In cattle and pigs, approximately half the administered dose is eliminated in the urine and the remainder in the faeces.
• In dogs, approximately 75% of the administered product is eliminated in the faeces; the remainder in the urine.

Elimination half-life / Clearance Rate

Elimination half-lives are species specific:

• Dogs: 12 to 36 hours (average 24 hours)
• Pigs: 4 hours / 2.5 hours
• Horses: 3 hours
• Cattle: 13 hours
• After SC administration in young cattle: 26 hours
• After SC administration in lactating cows: 17.5 hours.
• In rabbits: 
• After a single oral dose of 0.3 or 1.5 mg/kg, concentrations of drug in plasma decreased rapidly to near-undetectable levels by 24 hours after administration; the elimination half-life was about eight hours.
• After five days of administration at 0.3 or 1.5 mg/kg daily, no accumulation was noted at either dose rate and elimination was rapid once dosing stopped.

Drug Interactions

• Can displace, or be displaced by, other highly protein bound drugs such as warfarin and phenylbutazone.
• May antagonise the antihypertensive effects of ACE inhibitors.
• May cause increased likelihood of bleeding or gastric ulceration if used in conjunction with drugs that affect haemostasis, such as heparin or warfarin, or drugs that may cause gastrointestinal erosion, such as aspirin, flunixin, phenylbutazone, and corticosteroids.

Administration

Doses / Administration Routes / Frequencies

Cattle

• By subcutaneous or intravenous injection, 500 µg/kg as a single dose.

Dogs

• By mouth: 200 µg/kg as a single dose for 1 day, then 100 µg/kg once daily. Should be given soon after feeding.
• By subcutaneous injection: 200 µg/kg as a single dose.

Bears

• Has been given subcutaneously at 0.5 mg/kg once then orally at 0.1 mg/kg once daily (mixed with honey) for two weeks. (Used for alleviation of severe joint pain prior to treatment by femoral head and neck excision).

Lagomorphs - Oryctolagus cuniculus domesticus - Domestic rabbit:

• 100 - 300 micrograms orally once daily.
• 200 - 300 micrograms subcutaneously once daily.
• 0.2 - 0.6 mg/kg orally or subcutaneously. Duration of analgesic action possibly 24 hours.
• The oral suspension is generally palatable to rabbits.
• Note: based on a study in New Zealand White rabbits, "Rabbits may require a dose exceeding 0.3 mg/kg given once daily to achieve optimal plasma levels of meloxicam over a 24-h interval."
• 0.3 - 0.6 mg/kg subcutaneously or orally every 24 hours. "studies have shown that rabbits may require a dose exceeding 0.3 mg/kg every 24 hours to achieve optimal plasma levels of meloxicam over a 24-hour interval and doses of 1.5 mg/kg subcutaneously or orally are well tolerated for 5 days."

Withdrawal period / Withholding time

Cattle

• Meat and offal - 15 days.
• Milk - 5 days.

Pigs

• Meat and offal - 5 days.

Toxic Information

Toxic effects of Pharmaceutical Products

Contraindications / Precautions

• Not recommended for use in pregnant or lactating animals or in animals which are less than six weeks old.
• Contraindicated for use in individuals known to be hypersensitive to this drug.
• Contraindicated in individuals with active gastrointestinal ulceration or bleeding.
• Contraindicated in individuals with impaired renal, hepatic or cardiac function.
• Contraindicated in individuals with haemorrhagic disorders.
• Contraindicated for use in pregnant or lactating bitches.
• Use with extreme caution in individuals which are dehydrated, hypovolaemic or hypotensive as these conditions may potentially increase the risk of development of renal toxicity.

Adverse Effects / Side Effects / Warnings

• Occasional gastrointestinal distress in dogs, usually transient.
• Low renal toxicity.
• Prolonged use may cause gastro-intestinal lesions, inappetance, vomiting and diarrhoea.
• Serious side effects, including fatalities, have been recorded very rarely.

Detailed Toxicological Information

Reproductive effects

• Contraindicated for use in pregnant or lactating bitches.