Doses - PROCAINAMIDE HCL

Dogs:

a) 6 - 8 mg/kg IV over 5 minutes, then a constant rate of infusion at 25 - 40 micrograms/kg/min or 6 - 20 mg/kg IM q4-6h.
Oral dose: 8 - 20 mg/kg q6h if using regular tablets or capsules; if using Procan®-SR(Parke-Davis): 8 - 20 mg/kg q6-8 hours (Tilley and Miller 1986)
b) Add 500 - 1000 mg to 500 ml of D5W and give at slow infusion at a rate of 10 - 40micrograms/kg/min or to effect; or 10 - 20 mg/kg IM or PO tid-qid (Morgan 1988)
c) Initial maintenance dose: 15 mg/kg IV slowly q4h or 17.5 mg/kg PO q4h. Predictedserum values of 8 micrograms/ml are expected with this regimen. (Papich et al. 1986)
d) For VPC's: 6.6 - 22 mg/kg q4h PO (up to q8h if using sustained-release form¯maynot be absorbed).
For V tach: 6.6 - 8.8 mg/kg IV over 5 minutes, then infuse 11 - 40 micrograms/kg/min.(Ettinger 1989)

Horses:

a) Intravenous: 0.5 mg/kg every 10 minutes until resolution or until a total of 2 - 4 mg/kghas been given. (Muir and McGuirk 1987a)
Monitoring Parameters -

1) ECG; continuously with IV dosing

2) Blood pressure if possible, during IV administration

3) Symptoms of toxicity (see Adverse Reactions/Overdosage)

4) Serum levels
Because of the variability in pharmacokinetics reported in the dog, it is encouraged tomonitor therapy using serum drug levels. Because dogs apparently do not form the activemetabolite NAPA in appreciable quantities, the therapeutic range for procainamide iscontroversial. Therapeutic ranges from 3 - 8 micrograms/ml to 8 - 20 micrograms/ml havebeen suggested. This author would suggest using the lower range as a guideline to initiatetherapy, but not to hesitate increasing doses to attain the higher values if efficacy is notachieved and toxicity is not a problem. Digitalis-induced ventricular arrhythmias mayrequire substantially higher blood levels for control. Trough levels are usually specifiedwhen monitoring oral therapy. Because NAPA is routinely monitored with procainamidein human medicine, it may be necessary to request to your laboratory that NAPA valuesneed not be automatically run for canine patients.
Client Information - Oral products should be administered at evenly spaced intervals throughoutthe day/night. Unless otherwise directed, give the medication on an empty stomach at least 1/2 hourbefore feeding. Notify veterinarian if animal's condition deteriorates or symptoms of toxicity (e.g., vomiting, diarrhea, weakness, etc.) occur.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None

Human-Approved Products:

Procainamide HCl for injection 100 mg/ml in 10 ml vials & 500 mg/ml in 2 ml vials and 2 & 4ml syringes; Pronestyl® (Princeton Pharm.); Generic; (Rx)
Procainamide HCl Tablets or Capsules 250 mg, 375 mg, 500 mg; Pronestyl® (Princeton
Pharm.); Generic; (Rx)
Procainamide HCl Sustained-Release Tablets 250 mg, 500 mg, 1000 mg (Extended release only)(Note: These products are not recommended for initial therapy and have not been extensivelyused in veterinary medicine.); Pronestyl® SR (Princeton Pharm.), Procanbid® (Parke-Davis),
Generic; (Rx)