Amprolium 101
Amprolium is a synthetic analogue of thiamine (vitamin B1). By mimicking thiamine’s structure, it blocks Eimeria parasites from transporting the vitamin across their cell membranes, starving them without harming the host.
A Short History
- – Researchers at Merck & Co. identify thiamine analogue “CL 64855” with anticoccidial activity.
- – U.S. FDA approves liquid concentrate under the trade name Corid® for poultry.
- – Label expanded to cattle; powder formulations enter the market.
- – Remains first‑line therapy due to zero antibiotic resistance concerns.
How Does It Compare?
| Factor | Amprolium | Toltrazuril | Sulfa Drugs |
|---|---|---|---|
| Prescription | No (most regions) | Yes | No |
| Egg Withdrawal (hrs) | 0 | 96 | 24 |
| Resistance Risk | Low | Low | Moderate |
| Mode of Action | Thiamine analogue | Ionophore disruption | Folate inhibition |
| Cost per 100 kg | $$ | $$$$ | $ |