21 CFR §520.90b

(a) Specifications. Each capsule contains ampicillin trihydrate equivalent to 125, 250, or 500 milligrams of ampicillin.

(b) Sponsor. See No. 054771 in § 510.600(c) of this chapter.

(c) Conditions of use—(1) Dogs—(i) Amount. 5 to 10 milligrams per pound of body weight two or three times daily. In severe or acute conditions, 10 milligrams per pound of body weight, three times daily. Administer 1 to 2 hours prior to feeding. (ii) Indications for use. Treatment against strains of gram-negative and gram-positive organisms sensitive to ampicillin and associated with respiratory tract infections (tracheobronchitis and tonsillitis); urinary tract infections (cystitis); bacterial gastroenteritis; generalized infections (septicemia) associated with abscesses, lacerations, and wounds; and bacterial dermatitis. (iii) Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian. (2) Cats—(i) Amount. 10 to 30 milligrams per pound of body weight or three times daily. Administer 1 to 2 hours prior to feeding. (ii) Indications for use. Treatment against strains of gram-negative and gram-positive organisms sensitive to ampicillin and associated with respiratory tract infections (bacterial pneumonia); urinary tract infections (cystitis); and generalized infections (septicemia) associated with abscesses, lacerations, and wounds. (iii) Limitations. Federal law restricts this drug to use by or on the order of a licensed veterinarian.