Types of Insulin Used in Small Animal Practice

Insulin type	Route of admin.	Duration of action	Starting dosage	Conc.	Canine or feline use	Products avail. in US	Comments
Regular	IM, IV, SQ	Short: 4-6 h	0.1-0.2 U/kg	U-100	Both	Humulin R®	Only use in hospital
Neutral protamine hagedorn (NPH)	SQ	Intermediate: 8 h cats 10-12 h dogs	0.25-0.5 U/kg q12 h	U-100	Canine	Humulin N®, Novolin®	Don’t use in cats: Inadequate duration of action
Porcine zinc (lente)	SQ	Intermediate: 12 h	0.25-0.5 U/kg or 1-2 U/cat q 12 h	U-40	Both	Vetsulin®	Commonly used in dogs/cats
Protamine zinc (PZI)	SQ	Long: 12 h cats 12-24 h dogs	0.25-0.5 U/kg q 12 h cat q 12-24 h dog or 1-2 U/cat	U-40	Both	ProZinc®	May dose once daily in AM in some dogs
Glargine	SQ	Long: 12 h	0.25-0.5 U/kg q 12 h	U-100	Feline > canine	Lantus®	Commonly used in cats
Detemir	SQ	Long: 12 h	Dog: 0.1 U/kg q12 h Cat: 0.25-0.5 U/kg q 12 h	U-100	Canine (>10 kg) > feline	Levemir®	Not suitable for dogs <10 kg

Key:

IM: Intramuscular

IV: Intravenous

SQ: Subcutaneous

Always dose insulin based on (ideal) body weight, taking concurrent disease into consideration
Combine insulin therapy with appropriate dietary management to optimize glycemic control
Typically do not increase insulin dosage more frequently than every 1-2 wks
Although manufacturer guidelines typically recommend discarding insulin after 4-6 wks, most insulin is efficacious if stored in the fridge for 3-6 mos; discard insulin that is discolored or has other changes in appearance
Definition of diabetic control: Clinical signs of diabetes resolve; i.e., polyuria/polydipsia, weight loss, polyphagia; plus absence of hypoglycemia