Methazolamide
Also known as: Neptazane, GlaucTabs, Glaumetax, MZM
**Understanding the Medication:** Methazolamide is used to decrease the pressure inside your pet's eye(s) caused by glaucoma. It works by reducing the amount of fluid the eye produces. **Administration:** * **Give with food:** If this medication causes stomach upset (vomiting or loss of appetite), giving it with a meal can help. * **Do not crush or chew** unless directed by your veterinarian. **What to Watch For:** * **Heavy Panting:** This drug can cause a mild change in blood acidity (metabolic acidosis), which dogs often try to correct by panting heavily. Contact your vet if this seems excessive. * **Lethargy and Hiding:** Cats are especially sensitive to this medication and may become very tired or stop eating. * **Increased Thirst and Urination:** You may notice your pet drinking and urinating more than usual. * **Seek immediate veterinary care** if you notice abnormal bleeding or bruising, severe weakness, muscle tremors, or a skin rash.
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
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
- Medical treatment of glaucoma
How it is given
Possible side effects
- GI disturbances (vomiting, diarrhea, inappetence)
- Metabolic acidosis (often manifesting as heavy panting in dogs)
- CNS effects (sedation, depression, disorientation, excitement)
- Hematologic effects (bone marrow depression, thrombocytopenia)
- Renal effects (crystalluria, dysuria, renal colic, polyuria, polydipsia)
- Hypokalemia
- Hyperglycemia
- Hyponatremia
- Hyperuricemia
- Hepatic insufficiency
- Dermatologic effects (rash)
- Hypersensitivity reactions
- Weakness or cardiac arrhythmias (secondary to electrolyte imbalances)
Cautions & contraindications
- Significant hepatic disease (may precipitate hepatic coma)
- Renal or adrenocortical insufficiency
- Hyponatremia or hypokalemia
- Hyperchloremic acidosis or severe electrolyte imbalance
- Severe pulmonary obstruction (inability to increase alveolar ventilation to compensate for metabolic acidosis)
- Hypersensitivity to carbonic anhydrase inhibitors or sulfonamides
- Chronic, noncongestive, angle-closure glaucoma (long-term use may mask the condition by lowering IOP while angle closure progresses)
- > **Laboratory Interferences:** By alkalinizing the urine, carbonic anhydrase inhibitors may cause false-positive results in determining urine protein using bromphenol blue reagent, sulfosalicylic acid, nitric acid ring test, or heat and acetic acid test methods. They may also decrease iodine uptake by the thyroid gland in hyperthyroid or euthyroid patients. * Use with caution in pregnant animals (FDA Category C in humans; animal studies show adverse fetal effects). * Combining oral methazolamide with topical dorzolamide does not yield additive reductions in IOP and may increase adverse effects. * Monitor closely for signs of hypokalemia and metabolic acidosis, especially in cats.
Drug interactions
- Antidepressants, Tricyclic: Alkaline urine caused by methazolamide may decrease excretion of tricyclic antidepressants.
- Aspirin (or other salicylates): Increased risk of methazolamide accumulation and toxicity; increased risk for metabolic acidosis; methazolamide increases salicylate excretion.
- Digoxin: Methazolamide may cause hypokalemia, leading to an increased risk for digoxin toxicity.
- Insulin: Rarely, carbonic anhydrase inhibitors may interfere with the hypoglycemic effects of insulin.
- Methenamine compounds: Methazolamide alkalinizes urine, which may negate the urinary antiseptic effects of methenamine.
- Potassium-depleting drugs (corticosteroids, amphotericin B, corticotropin, diuretics): Concomitant use may exacerbate potassium depletion and hypokalemia.
- Phenobarbital: Increased urinary excretion due to alkaline urine, which may reduce phenobarbital serum levels.
- Primidone: May result in decreased primidone concentrations.
- Quinidine: Alkaline urine caused by methazolamide may decrease quinidine excretion.
Frequently asked questions
What is Methazolamide used for in pets?
**Understanding the Medication:** Methazolamide is used to decrease the pressure inside your pet's eye(s) caused by glaucoma. It works by reducing the amount of fluid the eye produces. **Administration:** * **Give with food:** If this medication causes stomach upset (vomiting or loss of appetite), giving it with a meal can help. * **Do not crush or chew** unless directed by your veterinarian. **What to Watch For:** * **Heavy Panting:** This drug can cause a mild change in blood acidity (metabolic acidosis), which dogs often try to correct by panting heavily. Contact your vet if this seems excessive. * **Lethargy and Hiding:** Cats are especially sensitive to this medication and may become very tired or stop eating. * **Increased Thirst and Urination:** You may notice your pet drinking and urinating more than usual. * **Seek immediate veterinary care** if you notice abnormal bleeding or bruising, severe weakness, muscle tremors, or a skin rash.
Is Methazolamide 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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