Oxytetracycline (± HCl; LA-200 long-acting)

What is this medication for?

• Ehrlichiosis/anaplasmosis (drug of choice), Potomac Horse Fever, Lyme, foal Lawsonia proliferative enteropathy; susceptible infections
• Anaplasmosis (control + carrier-state clearance), BRD, anthrax
• Enteritis/pneumonia, pregnant-ewe campylobacteriosis outbreaks
• Legacy — doxycycline/minocycline preferred

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• into a muscle tissue injury (Site-discipline related)

Worth a phone call to your veterinarian

• Renal injury (esp. foals/dehydration) (Monitor creatinine)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Collapse/arrhythmias on rapid into a vein (Rate-related (cattle esp.))

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Renal insufficiency; do not use in recently anthrax-vaccinated healthy animals (negates vaccine); young/pregnant (class)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Oral cations (Ca/Mg/Fe/Al — milk/dairy)
  • Antacids/sucralfate class
  • Warfarin

Storage and handling

into a vein: dilute and infuse slowly (collapse risk); into a muscle: neck only, ≤10 mL/site (myositis/abscess); phlebitis with into a vein — the administration-discipline drug.

Good to know

• The Rickettsia-family drug of horses: anaplasmosis/PHF/Lyme at 6.6 mg/kg diluted-slow — the dilution-and-rate rule IS the safety profile (tremors→collapse when rushed).
• Anaplasmosis double life: vector-season depot control (LA-200 q3–4 wk) vs carrier-clearance pulse (22 mg/kg × 5 d) — different jobs, different regimens.
• Foal Lawsonia sequence (oxytet into a vein → doxycycline by mouth) shows the class relay logic — into a vein potency then oral maintenance.
• The contracted-foal-tendon MMP trick (massive-dose laxity) is famous but lives in the older literature — know it as pharmacology trivia, verify against current sources before use.