Acetazolamide (a-set-a-ZOLE-a-mide) is a carbonic anhydrase inhibitor. Carbonic anhydrase is an enzyme that shifts the rate of reaction to favor the conversion of carbon dioxide and water into carbonic acid, bicarbonate ions, and free protons. Carbonic anhydrase activity is key to the regulation of pH and fluid balance in many different reactions throughout the body.
Fluid buildup can alter the shape of the eye and cause pressure on the optic nerve. Clinically, this condition is described as glaucoma. Inhibition of the enzymatic work of carbonic anhydrase activity (e.g., through the action of a carbonic anhydrase inhibitor) can lower fluid pressure in the eye.
Acetazolamide is used to treat a number of disorders, including the control of epileptic seizures in those individuals who suffer epilepsy .
Acetazolamide is also used to treat non-neurological disorders such as glaucoma (acetazolamide decreases pressure in the eye), and to reduce the symptoms of edema (an excess storage of water by the body that leads to localized swelling or puffiness) and altitude sickness.
Acetazolamide is prescription medication and is available only with a licensed physician's prescription. Acetazolamide is available in oral form in extended release capsules and tablets. Acetazolamide can also be administered by injection.
For both adults and children the recommended dosage for use in epilepsy cases is based upon actual body weight. In all cases, the exact dosage is determined by an experienced physician and/or pharmacist. In the most common cases, the normal recommended dosage is 4.5 mg per pound of body weight (10 mg per kg of body weight) and is administered in multiple (divided) doses delivered in the form of tablets or capsules.
Doses must be taken on a regular schedule but individuals should not double dose to make up for a missed dose.
When used to control anticonvulsive seizures, acetazolamide doses should not be stopped all at once. In most cases, physicians usually curtail (gradually lower) the dose an individual takes over time.
As with most prescription medicines, acetazolamide should stored in a safe place—away from the reach of children. Acetazolamide should also be stored in a dry area away from excessive heat or light. Outdated medicine (medicines past their expiration date) should be discarded in a container that is safe from the reach of children.
Women who are pregnant, plan to become pregnant, or who are breast-feeding infants should inform their physician of this fact before taking acetazolamide.
Unwanted side effects while taking acetazolamide include drowsiness, fatigue , or a dizzy lightheaded feeling. Individuals who experience these side effects should not operate machinery or drive while experiencing these symptoms. Other common side effects include shortness of breath.
Acetazolamide can also lead to excessive depletion (loss) of potassium from the body. To counter this potential loss, many physicians recommend that patients eat food or drink beverages such as orange juice to replace lost potassium. The loss of potassium does not occur in every case, however, and high levels of potassium can also be dangerous. Individuals who show signs of potassium loss—including, but not limited to, dryness of mouth, increased thirst, or muscle cramps—should alert their physician. Because diet can impact a number of health factors, individuals should only alter their diet after consulting their physician.
Individuals who are diabetic and who take acetazolamide may experience elevated sugar levels in their urine and blood.
Individuals who experience changes in their vision should also consult their physician.
In some rare cases, individuals may suffer depression , pains in the area of the kidneys, and bloody or black tarry stools.
Physicians and pharmacists are trained to evaluate the potential for adverse interactions by prescription drugs with other drugs. In the case of acetazolamide physicians evaluate potential adverse reactions with a range of drugs that include—but are not limited to—amphetamines, over-the-counter aspirins, cyclosporine, mood altering drugs (e.g., lithium), drugs used to control mental depression, drugs used to control irregular heartbeats, digoxin, diuretics (also known as water pills), and vitamins.
Varadkar S., J. S. Duncan, and H. Cross. "Acetazolamide and Autosomal Dominant Nocturnal Frontal Lobe Epilepsy." Epilepsia 44 (July 2003): 986.
Medline Plus. U.S. National Library of Medicine and the National Institutes of Health. <http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202114.html> (May 9, 2004).
National Eye Institute. 2020 Vision Place, Bethesda, MD 20892-3655. (301) 496-5248. <http://www.nei.nih.gov/>.