Methadyne

Before administration the body weight should be accurately determined.

Analgesia

To ensure accuracy of dosing in cats, an appropriately calibrated syringe should be used to administer the product.

As the individual response to methadone is variable, and depends partly on the dosage, the age of the patient, individual differences in pain sensitivity and general condition, the optimal dosing regimen should be individually based.

In dogs, onset of action is 1 hour following subcutaneous administration, approximately 15 minutes following intramuscular injection and within 10 minutes following intravenous injection. Duration of effect is approximately 4 hours following intramuscular or intravenous administration.

In cats, following intramuscular injection, onset of action is 15 minutes, and the duration of effect is 4 hours on average.

The animal should be examined regularly to assess if additional analgesia is subsequently required.

Premedication and/or neuroleptanalgesia

Dogs:

• Methadone HCl 0.5-1 mg/kg bodyweight, IV, SC or IM

(corresponding to 0.05 to 0.1 ml/kg)

Combinations e.g.:

• Methadone HCl 0.5 mg/kg bodyweight, IV (corresponding to 0.05 ml/kg), + e.g.

midazolam or diazepam

Induction with propofol, maintenance with isoflurane in oxygen.

• Methadone HCl 0.5 mg/kg bodyweight, IV (corresponding to 0.05 ml/kg), + e.g. acepromazine

Induction with thiopentone or propofol to effect, maintenance with isoflurane in oxygen or induction with diazepam and ketamine.

• Methadone HCl 0.5 -1.0 mg/kg bodyweight, IV or IM (corresponding to 0.05 to

0.1 ml/kg), + α2-agonist (e.g. xylazine or medetomidine)

Induction with propofol, maintenance with isoflurane in oxygen, in combination with fentanyl or total intravenous anaesthesia (TIVA) protocol: maintenance with propofol in combination with fentanyl.

TIVA protocol: induction propofol, to effect. Maintenance with propofol and remifentanil.

Chemical-physical compatibility has only been demonstrated for dilutions 1:5 with the following solutions for infusion: sodium chloride 0.9%, Ringer’s solution, and glucose 5%.

Cats:

• Methadone HCl 0.3-0.6 mg/kg bodyweight, IM (corresponding to 0.03 to

0.06 ml/kg)

▪Induction with benzodiazepine (e.g. midazolam) and dissociative (e.g.ketamine).

▪With a tranquiliser (e.g. acepromazine) and NSAID (meloxicam) or sedative (e.g. α2-agonist).

▪Induction with propofol, maintenance with isoflurane in oxygen.

Doses are dependent on the desired degree of analgesia and sedation, desired duration of effect and the concurrent use of other analgesics and anaesthetics.

When used in combination with other products, lower dosages can be used. For safe use with other veterinary medicinal products, reference must be made to the relevant product literature.