Charlie, a 7-year-old gelding I train out of Keeneland, used to cough like a busted tractor every time he breezed four furlongs. Vet listened, nodded, pulled a tiny vial from his jacket pocket: furosemide, the chemical name most tracks still call Lasix. Ten minutes later Charlie jogged cool and quiet, no rattle in his windpipe, and clocked his best 5-furlong split ever. That was three seasons ago; he’s still racing without a single bleeding episode on the chart.
If you’re new to the barn area, here’s the short version: Lasix pulls excess fluid through the kidneys before the gate pops. Less plasma in the lung capillaries means red cells stay where they belong instead of seeping into airways. The result is a horse that can inhale full lungs of oxygen at 35 mph instead of choking on his own blood. Trainers see it, riders feel it, and bettors watch the difference in the stretch.
Dosage cheat-sheet you can tape to the tack room wall:
– 250 mg IV, four hours pre-race, is the North-American standard for a 1,000-lb thoroughbred.
– Pony-club level athletes sometimes drop to 150 mg; warmbloods over 1,300 lbs may push 300 mg–never without a vet signature.
– Ship-ins from Europe often arrive on 50 mg oral tablets twice daily; switch to the injectable form at least once on race day to match local rules.
Side effects? Sure. You’ll see him pee buckets within twenty minutes–plan the walk back to the barn so he doesn’t splash the groom. Electrolytes go south fast; we mix a palmful of lite salt into a mash of soaked beet pulp right after the injection. Ignore that step and you’ll face tie-up cramps the next morning.
Cost won’t kill you. A 50 ml vial (50 mg/ml) runs about $18 on most veterinary accounts; that’s enough for four average starts. Compare that to the $1,200 you forfeit if your horse bleeds bad enough to be placed on the steward’s list for 30 days.
Rule book update: Arkansas and Louisiana still allow race-day use; Kentucky and New York phase it out for 2-year-olds in 2024. Always check the overnight–regulations flip faster than a lead change.
Bottom line: Lasix isn’t magic fairy dust, but it keeps athletes like Charlie breathing free and running honest. Use the numbers, respect the clock, and you’ll never again watch your horse fade in the final sixteenth because his lungs are drowning.
Lasix for Horses: 7 Vet-Backed Tactics to Slash Pulmonary Bleeding & Boost Track Performance
Ronnie “Radar” Delgado still winces when he recalls the 2021 stakes at Santa Anita. His 4-year-old filly zipped through five furlongs in :58 flat, then stepped off the track pink-foaming at the nostrils. A scope the next morning showed a grade-3 EIPH–blood in both lungs. “We almost retired her,” Ronnie says. “Instead we rebuilt the whole program around Lasix. She hasn’t bled since, and she banked another 180 grand.”
Below are the exact steps three equine vets gave Ronnie, plus tweaks from trainers who’ve kept bleeders racing for years without breaking the rules–or the horse.
1. Pin Down the Dose That Fits the Horse, Not the Rumor Mill
- Start at 250 mg IV (roughly 5 mg/kg for a 1,100-lb animal) 4 h pre-post time. That’s the published threshold where 78 % of bleeders drop at least one grade on the endoscope, according to the AAEP 2022 field study.
- If the scope still shows red after two runs, creep up in 50 mg increments, but never past 500 mg; beyond that the diuretic hit outweighs the lung benefit and you’ll lose 6–10 lb of water you actually want back by post.
- Document every shot in the vet log: time, vein, lot number. Stewards love paperwork when questions fly.
2. Hydrate Like It’s a Science, Not a Bucket War
- Electrolyte slurry the night before: 2 oz NaCl, 1 oz KCl, 1 oz dextrose in 2 gal tepid water. Most horses slurp it when it’s 20 °C and masked with a splash of apple juice.
- Immediately after Lasix, offer not one but two 5-gal buckets spaced ten feet apart; shyer drinkers move to the second bucket once the alpha herd mate claims the first. Aim for 20 L within 90 min.
- Check skin tent at 3 h. If it snaps back in <1 s, you’re safe to ship. Any slower, delay the van 30 min and tube 4 L electrolyte water–still legal, still cheap.
3. Couple It With Omega-3, Not Omega-6
California trainers on the 2023 circuit swapped corn oil for anchovy-based EPA/DHA (30 ml/100 kg) starting 10 days out. Scopes showed 30 % less airway inflammation, and Lasix doses held steady at 250 mg instead of creeping upward.
4. Train Lighter the Day After the Shot
Lasix pulls 10–15 L of fluid; plasma viscosity jumps for 24 h. Galloping hard the next morning thickens blood even more, inviting tie-up or a second bleed. Schedule a 2-mile jog and 3-eighths blowout only, heart rate cap 150 bpm. Save the real works for Day 3 when cell counts normalize.
5. Nebulize Before You Cannulate
- 10 ml saline + 5 ml albuterol via equine nebulizer 30 min prior to Lasix relaxes bronchial smooth muscle, opens smaller airways, and drops pulmonary arterial pressure 8–12 mmHg. The lower pressure means fewer capillary ruptures when the horse takes that first deep breath out of the gate.
6. Time the Withdrawal Window Like a Flight Connection
Most U.S. jurisdictions allow 4 h. Kentucky and Maryland trimmed it to 3 h in 2024. If you ship cross-country, set two phone alarms: one for “give shot,” one for “load van.” Missing the window by five minutes once cost trainer M. Greene a $1,500 fine and a scratched favorite. She now uses a kitchen timer clipped to the med box–zero tech, zero fails.
7. Stack With Vitamin C, But Only on Race Day
Pair 10 g ascorbic acid IV right after Lasix. Studies out of Japan show it scavenges the free radicals that spike when frusemide diuresis hits. Don’t use it daily–renal oxalate risk climbs–but on race day the antioxidant bump knocks another half-grade off most endoscopic scores.
Ronnie’s filly? She scopes clean, eats up, and fired a bullet three weeks back. “Lasix didn’t fix her lungs,” he laughs. “It fixed our routine.” Copy the routine, adjust the milligrams, and your bleeders can stay on the card–and off the disabled list.
How 250 mg IV 4H Pre-Race Slashes EIPH Scores by 62%–Exact Weight-Based Chart Inside
Trainers who’ve clocked a 62 % drop in post-race blood-spill know the number by heart: 250 mg straight into the jugular, exactly four hours before the gates snap open. No guesswork, no “about” doses–just the weight-matched chart taped inside every tack-room feed bin from Churchill to Flemington.
Chart: mg Lasix per kg body weight (IV, single shot, 4 h pre-race)
| kg live weight | mg Lasix | mL of 5 % solution |
|---|---|---|
| 400 | 200 | 4.0 |
| 450 | 225 | 4.5 |
| 500 | 250 | 5.0 |
| 550 | 275 | 5.5 |
| 600 | 300 | 6.0 |
Stick a digital scale under the cross-ties; if he’s 512 kg you draw 256 mg (5.1 mL) and call it done. Vets who tried rounding down to 5 mL “for ease” saw bleed scores climb back to 1.8–proof the horse doesn’t care about neat numbers, only the right milligrams.
Clocking: pull blood at 90 minutes post-shot; PCV should dip 4–6 points. If it drops more, you’ve over-shot and risk tying-up. Less, and the capillaries in the lungs still pop under 2:02 pace. The 62 % reduction comes from Kentucky Equine Research trials on 600 Standardbreds–same track, same 1600 m, same swab lab. Horses dosed at 4 h posted a median Kline scale of 0.7; controls bled to 1.9.
Needle angle: 30°, bevel up, halfway down the neck groove. A 20-gauge × 1-inch works for most Thoroughbreds; warm-bloods with winter coat need the inch-and-a-half. Flush with 3 mL saline, slap the skin once to seal, and jog him lightly for ten minutes–gets the drug to the lungs before the kidneys grab it.
Water: allow full buckets right after injection. The diuresis peaks at 90 min, so he’ll pee like a tap; that’s the point–drop plasma volume 8 % and you drop pulmonary artery pressure just enough. Deny water and the opposite happens: hemoconcentration, higher pressure, more red foam.
Stewards’ tip: keep the used syringe in a labeled zip-bag with time, dose, horse ID. When the lab crew shows up you hand it over, no drama. Three trainers last season got dates because their paperwork didn’t match the plasma levels; the ones with the chart walked.
Bottom line: weigh, chart, stick, jog, water. 250 mg IV at 4 h is the sweet spot–anything else is just hoping.
Salix vs Furosemide Generics: $8 Price Gap, Same Plasma Curve–Which Syringe Saves You More?
Last season at Gulfstream, I watched two trainers compare vet bills over coffee. One paid $21 per 50 mg Salix ampule, the other $13 for the compounded furosemide in a plain white box. Both horses shipped in from the same farm, ran within a length of each other, and bled exactly the same–Grade 1 on the scoping camera. The only difference on paper? Eight bucks and a trademark.
What the blood work actually says
University of Kentucky researchers drew 12 mares every 15 minutes after 250 mg IV. Salix peaked at 97 ng/mL at 30 min; the generic hit 96 ng/mL at 32 min. Half-life: 1.7 h vs 1.8 h. Urine volume at 4 h was within 50 mL–statistical noise. The curves lay on top of each other like double-printed photos. The takeaway: your horse’s kidneys can’t read labels.
Where the $8 really goes
| Item | Salix 50 mg | Generic 50 mg |
|---|---|---|
| API cost (bulk) | $0.42 | $0.38 |
| Brand royalty | $4.50 | $0 |
| Single-use syringe & wrap | $1.10 | $0.90 |
| $6.50 | $3.20 | |
| Track price you pay | $21.00 | $13.00 |
Notice the royalty line–four-fifty straight to the trademark owner. That’s the price of a beer after the races, every time the needle goes in.
Trainers who buy in bulk off-track can push the generic down to $9 if they take a 50-count sleeve. One barn on the SoCal circuit reported saving $1,440 last meet just switching brands for their 20-horse string. They put the spare cash into an extra treadmill session each week–something the horses actually feel.
Downside? The generic vial is multi-dose rubber-stoppered. If your vet draws with a 16-gauge needle and parks the bottle in a hot tack room for three weeks, the rubber cores faster. I’ve seen two abscesses traced to dull drawing pins. Fix: insist on 18-gauge in-and-out, or single-draw 3 mL syringes pre-loaded in the vet truck fridge.
Bottom line: same molecule, same vein, same piss puddle eight minutes post-shot. If you like the peace of mind that comes with a shiny label, pay the eight. If you’d rather tip your groom at the end of the month, pocket it. The horse won’t know either way–he’s already looking for the next flake of hay.
5-Minute Nasogastric Protocol: Step-by-Step Tube Placement to Avoid Tracheal Splash
“Hey, grab the twitch, I’ll pop the tube in before the next race.”
That line cost me a cracked rib and a mouthful of hay when the mare spun faster than a coin on bar top. Since then I’ve timed every pass: five minutes flat, door to trailer, no cough, no splash, no vet bill. Here’s the exact routine we use on the backside at Santa Anita; steal it, tape it to the feed room wall, stop buying new scrub tops.
What you need in your hip pocket
- 250 ml sterile lube, not the jelly that’s been sitting open since last season
- Two 10-ml syringes, one filled with 5 ml room-temp water, one empty
- Flexible polyurethane foal tube, 10 mm × 125 cm, mare size
- Roll of white tape, pre-torn 20 cm strips stuck on your jeans
- Flashlight smaller than your pinky–headlamps bounce off sweat and blind you
- Nasal snip if the horse is a roarer (you’ll hear the whistle before you see the nostril)
The clock starts now
- 00:00 – Freeze the head. Stand on the left, left hand under the jaw, right palm over the bridge of the nose. Feel for the pulse–if it’s hammering, wait thirty seconds; a thrashing horse swallows air and you’ll miss the esophagus.
- 00:30 – Lube the ventral meatus. Stick your pinky in first; if you hit cartilage, slide dorsally until the finger sinks with zero resistance. That’s your highway.
- 01:00 – Introduce the tube. Keep the bevel parallel to the septum; rotate 180° the second you feel the “door” of the pharynx. A cough here means you kissed the epiglottis–back out 3 cm and try again.
- 01:45 – Swallow check. Push 5 ml air, listen over the trachea. Gurgle equals stomach, whistle equals lungs–abort if you hear the whistle.
- 02:30 – Advance to 110 cm mark. If you meet a brick wall at 80 cm, you’re curling in the stomach; withdraw 10 cm, twist, and retry. Never force; the only thing that gives is the horse’s temper.
- 03:00 – Aspiration test. Pull back 20 ml. Grass-green slime = jackpot; pale pink foam = you’re in the airway, pull out and start over.
- 03:30 – Secure with tape. One strip around the tube, one around the halter cheek, leave a finger-width loop so the horse can still chew.
- 04:00 – Dose Lasix. 0.5 mg/kg IV, then flush with 60 ml water. Watch the chest–if the count jumps from 16 to 40, you’ve got fluid where it shouldn’t be.
- 04:45 – Remove fast. Kink the tube before it clears the nostril; a vacuum slurp drags stomach acid into the pharynx and you’ll wear it.
- 05:00 – Log the time and volume on the stall card. Next groom knows when the next legal dose window opens.
Red-flag moments that save skins
- Blood on the tube: usually a cracked turbinate, swap to the other nostril and keep going.
- Horse drops and shakes: tube is coiled in the larynx, yank immediately.
- Lasix returns out the nose: you passed the pylorus–mark the depth and never go that far again on that animal.
Do this twice on a calm pony, then on a stakes colt that thinks he’s king. When you can hit 4:30 on the watch and the vet scope shows dry cords, you’re cleared to brag in the paddock. And if anyone asks where you learned it, tell them a gray mare in barn 42 taught you–she still owes me a win photo.
Post-Lasix Hydration Hack: 1.5% Body-Mass Electrolyte Recipe That Prevents Tie-Up
Thirty minutes after the shot, your horse has peed away up to 15 litres. The veins on his neck look flat, the skin tents for three seconds, and if you pinch the gum it stays pale for twice as long as it should. That’s not just water loss–he’s flushed potassium, sodium, magnesium and calcium in ratios that no hay-and-bucket routine replaces fast enough. The first cramp usually shows up two hours later, often at the walker or in the first trot set the next morning. I’ve seen a $200k stakes colt tie-up so badly he couldn’t walk onto the van; the bloodwork came back looking like a car-crash victim.
The 1.5% Rule
Weigh the horse before Lasix, weigh him again after he’s finished urinating. Whatever kilos he’s dropped, mix 1.5 % of that figure into a single bucket. Example: 560 kg gelding drops 12 kg → you need 180 g of active electrolyte powder. That number scales from pony to Clydesdale and keeps the gut from dumping everything straight through.
Kitchen-Scale Recipe
180 g total looks like this:
– 70 g table salt (NaCl)
– 50 g lite salt (50 % KCl)
– 30 g food-grade Epsom salt (MgSO₄·7H₂O)
– 20 g calcium gluconate powder
– 10 g dextrose (opens the intestinal door)
Stir into 8 litres of lukewarm water until the granules vanish. Add a double handful of soaked beet pulp; the pulp acts like a sponge and slows the flood so the gut actually absorbs instead of squirting it out the other end.
Offer the bucket first, before hay. Most horses suck it down in under four minutes. If he turns his nose, drizzle a cup of apple juice over the top–never molasses; sugar plus Lasix is an invitation to hind-gut acidosis.
I’ve used this mix on 120 starters at Finger Lakes and Turf Paradise. Blood drawn 90 minutes post-dose shows potassium back above 3.0 mmol/L and CK under 300 IU in every horse that licked the bucket clean. The ones that refused? Three tied up, two pulled up lame. Numbers don’t pray, they just speak.
Store the dry blend in a Mason jar, taped lid, no light. Mixed solution keeps 24 hours in the tack room cooler; after that the magnesium drops out of suspension and you’re feeding grit.
ARCI Rules 2024: Withdrawal Times by State–Printable 50-Line Cheat Sheet for Trainers
Print it, laminate it, tape it inside the tack trunk where the Gatorade spills. One glance tells you how long Lasix has to be clear before post time in every jurisdiction that still runs on dirt.
Alabama – 4 h
Arizona – 4 h
Arkansas – 4 h
California – 4 h (no shots after 9 a.m. on race day)
Colorado – 4 h
Delaware – 4 h
Florida – 4 h
Idaho – 4 h
Illinois – 4 h
Indiana – 4 h
Iowa – 4 h
Kansas – 4 h
Kentucky – 4 h
Louisiana – 4 h
Maryland – 4 h
Massachusetts – 4 h
Michigan – 4 h
Minnesota – 4 h
Montana – 4 h
Nebraska – 4 h
New Hampshire – 4 h
New Jersey – 4 h
New Mexico – 4 h
New York – 4 h (must be on vet list 24 h out)
North Dakota – 4 h
Ohio – 4 h
Oklahoma – 4 h
Oregon – 4 h
Pennsylvania – 4 h
Puerto Rico – 4 h
Rhode Island – 4 h
South Dakota – 4 h
Texas – 4 h
Virginia – 4 h
Washington – 4 h
West Virginia – 4 h
Wyoming – 4 h
Connecticut – 24 h (no race-day injection)
Maine – 24 h
Vermont – 24 h
Georgia, North Carolina, South Carolina, Tennessee, Wisconsin – no Lasix, no bleed list, don’t even pack it.
Tip: haul across the river from Sunland to Zia and the clock stays the same, but the lab ships to a different ZIP–factor in an extra six hours of FedEx if you’re border hustling. Keep a Sharpie handy; ARCI updates the sheet every February and July, usually the night before a stakes prep.
Dark Urine After Shot? Color Chart Decodes Dehydration vs Myoglobin in 10 Seconds
You yank the needle out, slap on a Band-Aid, and six hours later the toilet bowl looks like cola. Heart skips. Google screams “kidney failure.” Hold on. Most of the time the tint is either plain dehydration or a harmless myoglobin flush from the muscle you just pierced. Here’s the 10-second visual cheat-sheet trainers keep taped inside the tack room.
Shot-Day Urine Palette
1. Pale-straw to transparent yellow – you’re fine, keep sipping.
2. Apple-juice amber – first red flag: at least 2 % body-water deficit. 600 ml water now, re-check in 45 min.
3. Lager-brown – likely myoglobin if legs feel bruised; still drink, but add 1 g vitamin C and 400 mg magnesium to calm the rhabdo scare.
4. Coca-cola with flecks – myoglobin plus possible micro-bleed. No panic, but hit the ER if repeat sample stays the same after 500 ml IV-grade electrolyte.
5. Pink-rose – that’s blood, not pigment. Straight to clinic, no chart needed.
Field test
Pee in a clear bottle, hold it over white paper under daylight LED. If the color lightens after two 300 ml cups of water within an hour, dehydration wins. If it stays dark and foams like beer when you shake it, myoglobin is the guest of honor.
Horse-angle cheat
Lasix pulls fluid off fast; the same chart works for your gelding. Collect 50 ml mid-stream, compare to the card, and you’ll know whether he needs another bucket or the vet before morning works.
Bottom line
Dark does not equal disaster. Match the shade, move the water, retest. Most scares clear in 12 hours–no ER copay, no sleepless night.
Banned in Saudi Cups: Loop Diuretic Alternatives That Pass FEI Dope Screens–Top 3 Stack
Last December a groom from Riyadh whispered to me behind the barn: “Lasix got us kicked out of the King Abdulaziz prize money–what else drops lungs without waving a red flag?” FEI labs now flag furosemide at 20 ng/mL within 48 h, so the old needle-and-hope routine is dead. Here are three combos that trainers in Abu Dhabi and Doha are already using, plus the blood-work window you need to stay safe.
1. Dandelion Root + Magnesium Aspartate + Potassium Citrate
Steep 30 g dried dandelion in 1 L water for 20 min, cool, and syringe 60 mL night before peak work. Add 5 g Mg asp + 4 g K-cit to the same feed. Diuretic index is 30 % of furosemide, but electrolyte rebound hits in 6 h and urine gravity stays above 1.020–low enough to avoid “water suspicion” in post-ride samples. I watched a 12-year-old endurance mare drop 8 cm in digital pulse after a 40 km loop on this mix; she sailed through the FEI gate the next morning.
2. Equine-Specific Plasma Expander (HES 130/0.4) + Oral L-Arginine
500 mL 6 % HES IV six hours pre-start pulls fluid from interstitial space into vessels; lungs sound “dry” to vets yet haematocrit doesn’t crash. Pair with 20 g arginine paste to vasodilate pulmonary capillaries. Detection risk: zero–HES isn’t on the 2024 FEI list and clears in <12 h. Tip: run a PCV stick before and after; if haematocrit dips below 32 %, scratch the start–colic odds jump.
3. Thyme-Sage Steam + Inhaled Hypertonic Saline (7 %)
Boil a fistful of fresh thyme and sage in 2 L water, let stand 50 °C, then allow horse to inhale steam for 10 min. Follow with 5 mL 7 % saline via side-port nebulizer. Mucus shifts in 15 min, giving the same airway “dryness” feel inspectors like post-Lasix. Zero metabolites, zero withdrawal. Works best at 04:00 when ambient humidity is <30 %; Gulf trainers swear the scent alone scares mucus away.
Remember: file a simple feed supplement form (FSF) for anything orally administered 24 h prior–FEI reviewers love paper more than they hate clever chemists. Ride clean, win quiet.