Acetazolamide 500mg ER Capsules

Acetazolamide is a potent carbonic anhydrase inhibitor. Carbonic anhydrase is an enzyme found in various tissues, including the renal tubules, ciliary body of the eye, and central nervous system. By inhibiting this enzyme, acetazolamide decreases the formation of bicarbonate and hydrogen ions. In the kidney, this leads to increased excretion of bicarbonate, sodium, potassium, and water, resulting in diuresis and metabolic acidosis. In the eye, it reduces the formation of aqueous humor, thereby lowering intraocular pressure. In the CNS, it may reduce abnormal neuronal discharge by increasing CO2 tension and decreasing neuronal excitability.

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:

Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat.
Signs of acidosis (too much acid in the blood): confusion, rapid breathing, rapid heartbeat, irregular heartbeat, severe stomach pain, nausea, vomiting, excessive sleepiness, shortness of breath, or feeling extremely tired or weak.
Signs of electrolyte problems: mood changes, confusion, muscle pain, cramps, or spasms, weakness, shakiness, balance disturbances, abnormal heartbeat, seizures, loss of appetite, or severe nausea and vomiting.
Signs of high or low blood sugar: fruity-smelling breath, dizziness, rapid breathing, rapid heartbeat, confusion, sleepiness, weakness, flushing, headache, unusual thirst or hunger, frequent urination, shaking, or sweating.
Changes in vision, eye pain, or severe eye irritation.
Changes in hearing.
Ringing in the ears.
Abnormal burning, numbness, or tingling sensations.
Painful urination or blood in the urine.
Difficulty urinating or changes in urine output.
Muscle weakness.
Balance disturbances.
Mobility problems.
Depression.
Confusion.
Seizures.

Rare but Serious Side Effects

In rare cases, severe and potentially life-threatening effects have occurred with sulfa drugs, including liver problems, blood disorders, and severe skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). If you experience any of the following symptoms, contact your doctor immediately:

Rash or red, swollen, blistered, or peeling skin.
Red or irritated eyes.
Sores in the mouth, throat, nose, or eyes.
Fever, chills, or sore throat.
New or worsening cough.
Extreme fatigue or weakness.
Bruising or bleeding.
Signs of liver problems: dark urine, fatigue, decreased appetite, nausea, stomach pain, light-colored stools, vomiting, or yellow skin and eyes.

Other Possible Side Effects

Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:

Diarrhea, nausea, or vomiting.
Changes in taste.
Decreased appetite.
Blurred vision.
Dizziness, sleepiness, tiredness, or weakness.
Headache.
Flushing.
Nervousness or excitability.

Reporting Side Effects

If you have questions about side effects or want to report any, contact your doctor or the FDA at 1-800-332-1088. You can also report side effects online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced.
A known sulfa allergy.
Certain health conditions, including:
+ Acidic blood problems
+ Kidney disease
+ Liver disease
+ Low potassium levels (hypokalemia)
+ Low sodium levels (hyponatremia)
+ Poor adrenal function
If you are currently taking methazolamide.

This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing health conditions and medications. Never start, stop, or change the dose of any medication without first consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.

Until you are aware of how this drug affects you, it is recommended that you avoid driving and other activities that require alertness and clear vision.

Regular blood tests and other laboratory assessments should be conducted as directed by your doctor to monitor your condition.

If you have diabetes (high blood sugar), it is crucial to closely monitor your blood sugar levels, as this medication may impact them. Additionally, be sure to notify all your healthcare providers and laboratory personnel that you are taking this drug, as it may affect the results of certain lab tests.

When taking this medication, you may be more susceptible to sunburn. Therefore, exercise caution when exposed to the sun, and inform your doctor if you experience increased sensitivity to sunlight.

If you are also taking aspirin, consult with your doctor, as combining high doses of aspirin with this medication has been associated with serious side effects, including loss of appetite, rapid breathing, lethargy, coma, and even death.

Older adults (65 years and above) should use this medication with caution, as they may be more prone to experiencing side effects.

In some cases, this drug may affect growth in children and teenagers. Regular growth checks may be necessary, so it is essential to discuss this with your doctor.

If you are pregnant, planning to become pregnant, or breastfeeding, it is vital to discuss the potential benefits and risks of this medication with your doctor to ensure the best possible outcome for you and your baby.

• Salicylates (high-dose): Concomitant use with high-dose aspirin or other salicylates can lead to severe toxicity, including metabolic acidosis and CNS depression, due to competition for renal tubular secretion and displacement from protein binding.
• Severe hepatic dysfunction/cirrhosis
• Severe renal impairment (CrCl < 10 mL/min)
• Marked hypokalemia
• Marked hyponatremia
• Adrenal insufficiency
• Hyperchloremic acidosis

• Methenamine: Acetazolamide can alkalinize urine, reducing the effectiveness of methenamine as an antibacterial agent.
• Other Carbonic Anhydrase Inhibitors (e.g., dorzolamide, brinzolamide): Increased risk of systemic adverse effects.
• Lithium: Acetazolamide may increase lithium excretion, leading to decreased lithium levels and potential loss of therapeutic effect.
• Cyclosporine: Acetazolamide may increase cyclosporine levels, increasing the risk of nephrotoxicity and neurotoxicity.

• Diuretics (e.g., loop, thiazide): Additive diuretic and potassium-wasting effects, increasing risk of hypokalemia.
• Corticosteroids: Increased risk of hypokalemia.
• Amphotericin B: Increased risk of hypokalemia.
• Antiepileptic drugs (e.g., phenytoin, carbamazepine): Acetazolamide may alter levels of these drugs; monitor closely.
• Digoxin: Hypokalemia induced by acetazolamide can potentiate digoxin toxicity.
• Oral Hypoglycemics: May alter blood glucose levels; monitor closely.
• Sodium Bicarbonate: May exacerbate metabolic acidosis.

• Not specifically categorized as minor, but general caution with drugs affecting electrolytes.

• Paresthesias (tingling sensation in extremities)
• Fatigue, lethargy, confusion (signs of metabolic acidosis or electrolyte imbalance)
• Nausea, vomiting, loss of appetite
• Muscle weakness, cramps, irregular heart beat (signs of hypokalemia)
• Skin rash, Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN) - severe dermatologic reactions
• Fever, sore throat, unusual bleeding/bruising (signs of blood dyscrasias)
• Flank pain, hematuria (signs of renal calculi)
• Signs of hepatic encephalopathy (in patients with liver disease)

Acetazolamide is classified as Pregnancy Category C. Animal studies have shown teratogenic effects (e.g., limb defects) at doses higher than human therapeutic doses. There are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Acetazolamide is excreted in human milk in small amounts. While the amount is generally considered low, there is a theoretical risk of adverse effects in the infant, such as metabolic acidosis or sulfonamide-related reactions (e.g., hypersensitivity, jaundice in G6PD deficient infants). The American Academy of Pediatrics considers it compatible with breastfeeding, but caution is advised, especially in premature infants or those with underlying conditions.

The extended-release formulation is generally not recommended or studied in pediatric patients. Immediate-release acetazolamide may be used for specific indications (e.g., glaucoma, epilepsy, hydrocephalus) in children, but dosing must be carefully individualized and monitored due to increased risk of metabolic acidosis and other adverse effects.

Elderly patients may be more susceptible to the adverse effects of acetazolamide, particularly electrolyte imbalances (hypokalemia, hyponatremia), metabolic acidosis, and renal impairment. Dosage adjustments may be necessary based on renal function. Start with lower doses and titrate slowly, monitoring closely for adverse reactions.

• Acetazolamide is a sulfonamide derivative; caution should be exercised in patients with a history of sulfonamide allergy, although cross-reactivity is not absolute.
• Paresthesias (tingling sensations) are a very common side effect, often benign, and usually do not require discontinuation of therapy.
• Patients should be advised to maintain adequate fluid intake to minimize the risk of renal calculus formation.
• Long-term use can lead to chronic metabolic acidosis, which may require bicarbonate supplementation.
• The ER formulation is designed for once-daily dosing, improving compliance compared to immediate-release forms.

• For Glaucoma: Topical beta-blockers (e.g., timolol), prostaglandin analogs (e.g., latanoprost), alpha-adrenergic agonists (e.g., brimonidine), topical carbonic anhydrase inhibitors (e.g., dorzolamide, brinzolamide), miotics (e.g., pilocarpine), laser therapy, surgical interventions.
• For Acute Mountain Sickness: Dexamethasone (alternative for prevention/treatment), gradual ascent.
• For Edema (though ER not primary for this): Loop diuretics (e.g., furosemide), thiazide diuretics (e.g., hydrochlorothiazide).

If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.