Nicarbazin: veterinary dose and monograph

At a glance

Drug class

Antiparasitic

Also known as

Nicarb, Maxiban (with narasin), Nicarbazin

Species with doses

Poultry

Routes

PO

Last reviewed

1 October 2026

Indications

• Prevention of coccidiosis (Eimeria) in broiler chickens (in feed)
• Coccidiosis control in rotation/shuttle programmes (often with narasin)

Nicarbazin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Poultry

• Coccidiosis prevention (broilers, in feed): Label-sourced — neither Papich 5e nor Plumb’s has a nicarbazin monograph. Inclusion rates differ for nicarbazin alone and nicarbazin–narasin combinations; follow the local label, including its pre-slaughter withdrawal. Not for laying hens (egg-shell and hatchability effects); heat-stress risk in hot weather.

Contraindications

LAYING / breeding hens (egg defects, reduced hatchability). Hot-weather/heat-stress conditions (reduces heat tolerance — increased mortality). Species other than label poultry. Observe withdrawal. Known hypersensitivity.

Species-specific warnings

Birds: Do NOT feed to laying/breeding hens (mottled yolks, reduced hatchability/production) and avoid during heat stress (increased mortality). Broiler use only.

Adverse effects

• Reduced HEAT-STRESS tolerance → increased mortality in hot conditions
• Egg-quality defects (mottled yolks, reduced production/hatchability) in layers/breeders
• Reduced weight gain at high inclusion

Drug interactions

• Narasin (ionophore): synergistic combination (Maxiban) for efficacy and resistance management
• No major host therapeutic interactions

Pregnancy and lactation

Not applicable (broiler feed additive); explicitly NOT for breeding/laying birds.

Monitoring

• Coccidiosis control (oocyst counts/lesion scores) in the flock
• Ambient temperature (withdraw/avoid in heat stress)
• Confirm it is broiler (not layer/breeder) feed
• Withdrawal-period compliance

Toxicity and overdose

The key "toxicities" are management-related: increased mortality from reduced HEAT-STRESS tolerance in hot weather, and egg-quality/production defects if fed to layers/breeders. High feed inclusion can depress weight gain. Otherwise reasonably tolerated in broilers within label limits.

Management: Remove the medicated feed; provide supportive care and reduce heat stress (cooling, ventilation, water). No specific antidote. Manage affected layers by withdrawal (egg effects are reversible after withdrawal).

Clinical pearls

• A broiler anticoccidial — but remember the two big rules: NOT for layers/breeders (egg defects) and withdraw in HOT weather (it reduces heat tolerance → mortality)
• Often paired with narasin (Maxiban) for synergy and resistance management in shuttle/rotation programmes
• It prevents, not treats — part of a feed-based coccidiosis-control strategy
• Confirm the medicated feed reaches only broilers, never the layer house

Mechanism of action

A coccidiostat (an equimolar complex of 4,4′-dinitrocarbanilide and 2-hydroxy-4,6-dimethylpyrimidine) that disrupts energy metabolism in the second-generation schizont stage of Eimeria, inhibiting parasite development in the gut. Its action on cellular energy metabolism also impairs the bird's thermoregulatory tolerance (the basis of the heat-stress caution) and disturbs egg formation in layers.

Formulations and products

• Feed premix (broiler anticoccidial)
• Maxiban — nicarbazin + narasin combination premix
• Maxiban (Elanco) — Nicarbazin + narasin premix, Feed premix

Storage

Premix: 15–30 °C, dry, protect from light/moisture; mix uniformly into broiler feed only.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antiparasitics

• Monensin
• Monepantel
• Morantel
• Moxidectin
• Niclosamide
• Nitenpyram
• Nitroxynil
• Oxfendazole

Frequently asked questions