In poultry farming, drug-drug interactions can significantly impact the health and productivity of birds. These interactions can alter the efficacy, toxicity, or pharmacokinetics of the drugs involved. Below is a list of common drug-drug interactions in poultry:

### 1. Antibiotics and Antacids
- Interaction: Antacids containing aluminum, magnesium, or calcium can reduce the absorption of certain antibiotics (e.g., tetracyclines, fluoroquinolones).
- Effect: Decreased antibiotic efficacy.

### 2. Tetracyclines and Calcium
- Interaction: Calcium supplements or calcium-rich feed can bind to tetracyclines (e.g., oxytetracycline, chlortetracycline).
- Effect: Reduced absorption and efficacy of tetracyclines.

### 3. Sulfonamides and Vitamin K
- Interaction: Sulfonamides (e.g., sulfadimethoxine) can inhibit vitamin K synthesis by gut bacteria.
- Effect: Increased risk of bleeding due to vitamin K deficiency.

### 4. Aminoglycosides and Loop Diuretics
- Interaction: Concurrent use of aminoglycosides (e.g., gentamicin) and loop diuretics (e.g., furosemide) can increase the risk of nephrotoxicity and ototoxicity.
- Effect: Kidney damage and hearing loss.

### 5. Coccidiostats and Certain Antibiotics
- Interaction: Ionophore coccidiostats (e.g., monensin, lasalocid) can interact with tiamulin or sulfonamides.
- Effect: Increased risk of toxicity, including muscle weakness and death.

### 6. Chloramphenicol and Penicillins
- Interaction: Chloramphenicol can antagonize the bactericidal activity of penicillins (e.g., amoxicillin).
- Effect: Reduced efficacy of penicillins.

### 7. Macrolides and CYP450 Enzyme Inhibitors
- Interaction: Macrolides (e.g., erythromycin, tylosin) can inhibit cytochrome P450 enzymes, affecting the metabolism of other drugs.
- Effect: Increased plasma levels of drugs metabolized by CYP450, leading to potential toxicity.

### 8. Fluoroquinolones and Divalent Cations
- Interaction: Fluoroquinolones (e.g., enrofloxacin) can chelate with divalent cations (e.g., calcium, magnesium, iron) in feed or water.
- Effect: Reduced absorption and efficacy of fluoroquinolones.

### 9. Anticoagulants and Sulfonamides
- Interaction: Sulfonamides can displace anticoagulants (e.g., warfarin) from plasma proteins.
- Effect: Increased anticoagulant activity and risk of bleeding.

### 10. Vitamin E and Selenium with Anticoagulants
- Interaction: High doses of vitamin E and selenium can enhance the effects of anticoagulants.
- Effect: Increased risk of bleeding.

### 11. Niacin and Antitubercular Drugs
- Interaction: Niacin can interact with antitubercular drugs (e.g., isoniazid).
- Effect: Reduced efficacy of niacin and potential for toxicity.

### 12. Probiotics and Antibiotics
- Interaction: Antibiotics can kill or inhibit the growth of probiotic bacteria.
- Effect: Reduced efficacy of probiotics.

### 13. Corticosteroids and NSAIDs
- Interaction: Concurrent use of corticosteroids (e.g., dexamethasone) and nonsteroidal anti-inflammatory drugs (NSAIDs) can increase the risk of gastrointestinal ulcers.
- Effect: Increased risk of gastrointestinal bleeding.

### 14. Anthelmintics and Fat-Soluble Vitamins
- Interaction: Some anthelmintics (e.g., fenbendazole) can interfere with the absorption of fat-soluble vitamins (A, D, E, K).
- Effect: Potential vitamin deficiencies.

### 15. Tiamulin and Monensin
- Interaction: Tiamulin can potentiate the toxicity of monensin.
- Effect: Increased risk of muscle damage and death.

### 16. Enrofloxacin and Theophylline
- Interaction: Enrofloxacin can inhibit the metabolism of theophylline.
- Effect: Increased theophylline levels and potential toxicity.