Equine Systemic Antibiotic Therapies for First Aid: 2025 American Guide to the Top 6 Evidence-Based Options to Protect Your Horse, with Stewardship, Withdrawal Times, Administration and Monitoring

Excenel RTU EZ is a ready-to-use ceftiofur formulation favored in equine practice for reliable beta-lactam broad-spectrum coverage and the convenience of a pre-mixed injectable. It earns a best-in-class position for combining strong activity against common equine pathogens with reduced preparation time and lower waste compared with multi-component generics, though its acquisition cost is typically higher than basic tetracyclines.

Trimidox Oral Powder is positioned as a best-in-class equine systemic oral broad spectrum antibiotic because of its concentrated powder formulation that enables flexible, weight-based dosing for herd-level or individual treatment; this makes it cost-efficient for larger stables compared with single-dose pastes. Technically it stands out for stability in feed mixes and straightforward reconstitution versus liquid suspensions like Sulfatrim, while offering more dosing precision than fixed-dose pastes such as Tribrissen.

Gentocin Injectable (gentamicin) is a cost-efficient aminoglycoside favored for targeted culture-guided treatment of Gram-negative equine infections due to its potent bactericidal activity and rapid onset. Relative to the cephalosporins and fluoroquinolone in this list, Gentocin offers a lower acquisition cost and useful synergism with beta-lactams, though it requires more careful dosing and renal monitoring to manage nephrotoxicity risk.

Doxycycline Hyclate 100mg Tablets are considered best-in-class for intracellular and atypical equine infections identified by sensitivity testing, combining good oral bioavailability and once- or twice-daily dosing that improves compliance and lowers administration labor costs. Compared with other products here, doxycycline offers a favorable balance of broad intracellular coverage, predictable pharmacokinetics, and generally affordable pricing, making it a frequent choice when sensitivity profiles support tetracycline-class therapy.

Penicillin G Procaine is a long-established, low-cost beta-lactam routinely used for equine abscesses because of reliable efficacy against gram-positive organisms and many anaerobes commonly implicated in wound infections. Its financial and safety advantages make it a first-line field choice, though compared with broad-spectrum agents like Excenel or Baytril it has limited gram-negative coverage and is often paired with drugs such as gentamicin when broader empiric coverage is needed.