Corticotropin: what the FDA reviewed for dog products

ACTH Gel NADA 140-583, Original approval, November 14, 1988; sponsor Bimeda Animal Health Ltd.; species: Dogs, Cats; foi_id 1727; FDA PDF

Indication

Primarily a diagnostic aid to test for adrenal dysfunction in dogs; also stimulation of the adrenal cortex where there is a general deficiency of ACTH in dogs and cats.

Dose regimen

2.2 IU/kg (1 IU/lb) for the ACTH stimulation test (from the cited literature protocols), Intramuscular for diagnostic use in dogs; intramuscular or subcutaneous for ACTH deficiency in dogs and cats, single injection, plasma cortisol sampled before and 2 hours after, Diagnostic protocol; the summary's General Information section lists no recommended dosage field.

Plasma samples are obtained for cortisol determination before and 2 hours following an intramuscular injection of ACTH gel of 2.2 IU/kg (1 IU/Ib).

Effectiveness

Published well-controlled study (Lorenz 1982, JAAHA): ACTH stimulation test in 57 consecutive dogs with spontaneous hyperadrenocorticism, each dog its own control; plasma cortisol before and 2 hours after 2.2 IU/kg ACTH gel intramuscularly, assayed by competitive protein binding (21 dogs) or radioimmunoassay (36 dogs).; n = 57; primary endpoint: Plasma cortisol concentration pre- and 2 hours post-ACTH; result: Marked cortisol elevation after ACTH gel: CPB mean 87.2 to 399.0 ng/mL (21 dogs); RIA mean 74.40 to 369.19 ng/mL (36 dogs); the differential response between normal and hyperadrenocorticoid dogs makes the test a useful diagnostic aid.

The ACTH stimulation test was used an an aid in the diagnosis of spontaneous hyperadrenocorticism in 57 dogs.

Extraction notes: Original NADA (1988) filed as a generic equivalent to Adrenomone for the therapeutic claim (NAS/NRC-reviewed; bioequivalence shown by vasopressin activity test and USP conformance). The diagnostic claim rests on published literature (Lorenz 1982; Feldman & Peterson 1984 with 65 normal and 30 hypoadrenocorticoid dogs; protocols from Peterson 1986 and Feldman & Nelson 1987). No target animal safety studies were conducted ('The drug is reviewed by NAS/NRC and deemed safe for the therapeutic claim'). The cortisol result values are from a flattened table. Effectiveness quote reproduces the source typo 'an an'; dose quote reproduces 'IU/Ib'. Species recorded as 'Dogs, Cats' exactly as stated.