Alendronate Sodium
Also known as: Fosamax, Adronat, Alendros, Arendal, Onclast
**Important Administration Instructions for Pet Owners:** * **Strict Fasting:** This medication will not be absorbed if given with food. It must be given on an empty stomach, and you must withhold food for at least 30 minutes after dosing. * **Preventing Esophageal Damage:** Alendronate can cause severe ulcers in the esophagus if it gets stuck. * *For Dogs:* Walk or play with your dog for 30 minutes after giving the pill to keep them upright and ensure the pill reaches the stomach. * *For Cats:* Give the pill followed immediately by at least 6 mL (about a teaspoon) of water via syringe. Buttering your cat's lips afterward encourages swallowing and salivation, helping the pill go down safely. * **Watch for Side Effects:** Contact your veterinarian immediately if your pet shows signs of drooling, regurgitation, difficulty swallowing, vomiting, or loss of appetite. * **Investigational Use:** Understand that the use of this drug in veterinary medicine is relatively new, and long-term effects in pets are still being studied.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Feline odontoclastic resorptive lesions (FORLs)
- Idiopathic hypercalcemia (after dietary change has been attempted)
- Refractory hypercalcemia
- Investigational treatment of histiocytic sarcoma complex
How it is given
Possible side effects
- Upper GI irritation and erosions
- Esophageal stricture or ulceration
- Vomiting
- Inappetence
- Jaw osteonecrosis (rare but documented in humans)
- Musculoskeletal pain
- Hypocalcemia (with overdose)
- Hypophosphatemia (with overdose)
Cautions & contraindications
- Esophageal abnormalities (e.g., strictures, achalasia) that delay esophageal emptying
- Inability to stand or sit upright for 30 minutes post-administration (human guideline; veterinary relevance is managed via water chasers/activity)
- Severe renal dysfunction (Creatinine Clearance < 35 mL/min)
- Known hypersensitivity to alendronate or other bisphosphonates
- > **Esophageal Toxicity Warning:** Alendronate can cause severe local irritation to the upper gastrointestinal mucosa. * **Administration Technique:** To minimize esophageal transit time and prevent erosions, ensure the patient swallows the medication completely. In dogs, walking or playing for 30 minutes post-dose is recommended. In cats, administering at least 6 mL of water and buttering the lips to induce salivation is advised. * **Renal Impairment:** Use with extreme caution or avoid in patients with severe renal dysfunction. * **Investigational Use:** Inform owners that the use of this drug in veterinary medicine is largely investigational, and long-term safety data is lacking.
Drug interactions
- Aspirin: Increased risk of upper GI adverse effects and erosions.
- Calcium-containing oral products or food: Likely to significantly decrease the already low oral bioavailability of alendronate.
- Ranitidine (IV): Increased oral alendronate bioavailability two-fold in a human study.
- NSAIDs: Humans taking NSAIDs with alendronate had no higher rates of GI adverse reactions than when NSAIDs were used with placebo, though caution is still advised.
- Antacids (Aluminum, Magnesium, Calcium): Significantly decreases alendronate absorption
- Iron supplements: Decreases alendronate absorption
Frequently asked questions
What is Alendronate Sodium used for in pets?
**Important Administration Instructions for Pet Owners:** * **Strict Fasting:** This medication will not be absorbed if given with food. It must be given on an empty stomach, and you must withhold food for at least 30 minutes after dosing. * **Preventing Esophageal Damage:** Alendronate can cause severe ulcers in the esophagus if it gets stuck. * *For Dogs:* Walk or play with your dog for 30 minutes after giving the pill to keep them upright and ensure the pill reaches the stomach. * *For Cats:* Give the pill followed immediately by at least 6 mL (about a teaspoon) of water via syringe. Buttering your cat's lips afterward encourages swallowing and salivation, helping the pill go down safely. * **Watch for Side Effects:** Contact your veterinarian immediately if your pet shows signs of drooling, regurgitation, difficulty swallowing, vomiting, or loss of appetite. * **Investigational Use:** Understand that the use of this drug in veterinary medicine is relatively new, and long-term effects in pets are still being studied.
Is Alendronate Sodium safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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