Merck Manual

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Dosage of Analgesics

Dosage of Analgesics

Drug

Dogs

Cats

Ferrets

Rabbits

Horses

Cattle

Pigs

Opioid Analgesicsa

Buprenorphine

0.01–0.02 mg/kg, SC, bid

0.01–0.03 mg/kg, SC or IM, bid

0.01–0.03 mg/kg, IV, IM, or SC, bid-tid

0.02–0.05 mg/kg, SC, IM, or IV, bid

0.005–0.02 mg/kg, IM or IV, bid-qid

Butorphanol tartrate

0.2–0.4 mg/kg, IM or SC; 0.55 mg/kg, PO, every 6–12 hr

0.1–0.2 mg/kg, IV; 0.2–0.4 mg/kg, IM or SC, every 4 hr

0.05–0.4 mg/kg, IM, every 4–6 hr

0.1–0.5 mg/kg, IV, every 4 hr

0.05–0.1 mg/kg, IV, IM, or SC

Adult: 20–30 mg, IV, jugular

0.1–0.3 mg/kg, IM

Medetomidine

0.002–0.03 mg/kg, IM, IV, or SC

0.002–0.03 mg/kg, IM, IV, or SC

Meperidine hydrochloride

2–10 mg/kg, IM or SC, every 2 hr

2–5 mg/kg, IM or SC, every 2 hr

2–5 mg/kg, IM or SC, every 2–4 hr

5–10 mg/kg, IM or SC, every 2–3 hr

0.2–0.4 mg/kg, IV; 1–3 mg/kg, IM or SC

500 mg/cow, IV slowly, IM or SC

1–2 mg/kg, IM or IV

Morphine sulfate

0.22–0.88 mg/kg, IM, IV slowly, or SC, every 4–6 hr as needed

0.1 mg/kg, IM or SC, as needed

0.5–5 mg/kg, IM or SC, qid

2–5 mg/kg, SC or IM, every 2–4 hr

0.2 mg/kg, IV; 0.2–0.4 mg/kg, IM

0.2–1 mg/kg, IM, every 4 hr

Nalbuphine

0.5–2 mg/kg, SC, every 4–8 hr

1.5–3 mg/kg, IV, every 3 hr

1–2 mg/kg, IV, every 4 hr

Oxymorphone hydrochloride

0.05–0.1 mg/kg, IV, IM, or SC, every 1–3 hr

0.025–0.05 mg/kg, IV, IM, or SC

0.05–0.2 mg/kg, IV or IM, bid-qid

0.1–0.2 mg/kg, IM, every 2–4 hr

0.02–0.03 mg/kg, IV or IM

0.075 mg/kg, IM

Pentazocine lactate

2–3 mg/kg, IM, every 4 hr; 15 mg/kg, PO, tid

5–10 mg/kg, SC or IM, every 4 hr

10–20 mg/kg, SC or IM, every 4 hr; 5 mg/kg, IV, every 2–4 hr

0.33 mg/kg, IV

2–5 mg/kg, IM, every 4 hr

Nonopioid Sedative Analgesics

Xylazine hydrochloride

0.5–1 mg/kg, IV; 1–2 mg/kg, IM or SC

0.5–1 mg/kg, IV; 1–2 mg/kg, IM or SC

1 mg/kg, IM or SC

0.1–1 mg/kg, IV; 0.5–1 mg/kg, IM or SC

0.05–0.1 mg/kg, IV; 0.1–0.2 mg/kg, IM

2 mg/kg, IM

Detomidine

0.02–0.04 mg/kg, IV or IM

Nonpsychotropic Analgesics

Acetaminophen

15 mg/kg, PO, qid as needed

Contraindicated

Aspirin

10–25 mg/kg, PO, bid

10 mg/kg, PO, every 48 hr

0.5–20 mg/kg, PO, once to three times daily

5–20 mg/kg/day, PO

30–47.5 mg/kg, PO, bid-qid

26 mg/kg, IV; 100–124 mg/kg, PO, bid

10–20 mg/kg, PO, every 4 hr as needed

Carprofen

4 mg/kg/day, IV or SC

4 mg/kg/day, IV or SC

1.5 mg/kg, PO, bid

0.7 mg/kg/day, IV, IM, or SC

0.7 mg/kg/day, IV, IM, or SC

Dipyrone

28 mg/kg, IV, IM, SC, or PO, tid

28 mg/kg, IV, IM, SC, or PO, tid

5–10 g/horse, IV or IM, tid as needed

50 mg/kg, IV, IM, or SC

50 mg/kg, IV, IM, or SC

Flunixin meglumine

1–2 mg/kg/day, PO, IV, or IM, up to 3 days; use of flunixin meglumine in dogs has decreased since the introduction of other NSAIDs with higher therapeutic indexes.

Use of flunixin meglumine in cats has decreased since the introduction of other NSAIDs with higher therapeutic indexes.

0.5–2 mg/kg, SC, once to twice daily

1.1 mg/kg, SC or IM, bid

1–2.2 mg/kg, IV; 2.2 mg/kg/day, IM or PO

1.1–2.2 mg/kg, IM or PO, once to three times daily

1–2 mg/kg/day, IV or IM

Ketoprofen

2 mg/kg/day, SC, IM, or IV, up to 3 days; 1 mg/kg/day, PO, up to 5 days

1 mg/kg/day, SC up to 3 days, or PO up to 5 days

3 mg/kg, IM

2.2 mg/kg/day, IV

2.2 mg/kg, IV; 3 mg/kg/day, IM

Meclofenamic acid

2.2 mg/kg/day, PO

2.2 mg/kg/day, PO

2.2 mg/kg/day, PO

Phenylbutazone

15–22 mg/kg, PO; 15 mg/kg, IV, bid-tid (maximum 0.8 g/dog/day or 44 mg/kg/day); use of phenylbutazone in dogs has decreased since the introduction of other NSAIDs with better safety margins.

15 mg/kg, IV, tid; 10–14 mg/kg, PO, bid; use of phenylbutazone in cats has decreased since the introduction of other NSAIDs with better safety margins.

4.4 mg/kg, PO, bid on day 1; 2.2 mg/kg, PO, bid for 4 days; 2.2 mg/kg, PO, daily or every other day

2–5 mg/kg, IV; 4–8 mg/kg, PO

2–5 mg/kg, IV; 4–8 mg/kg, PO

a Recommended dosages of opiates may produce excitement in cats and horses.