Topamax is a prescription medication sold under the generic name topiramate. Though it is most commonly prescribed to treat seizures and for prevention of migraine headaches, it is also used for the treatment of sleep eating. How does Topamax work and what are the most common side effects?
Uses of Topamax
Topamax may be prescribed to treat sleep-related eating disorder (SRED). It is more frequently used to treat seizures that occur as part of epilepsy. It has also been found to be effective to prevent migraine headaches from recurring and may be taken as prophylaxis.
How Does Topamax Work?
The exact mechanism of action explaining how Topamax works is not known. It blocks sodium channels in the body which open and close in response to specific levels of charged chemicals. It also enhances the activity of a chemical messenger, or neurotransmitter, called GABA. In addition, it interferes with receptors on cells for a chemical called glutamate. It also inhibits an enzyme called carbonic anhydrase.
Who Should Not Use Topamax?
Topamax should not be used if you are pregnant. Caution is advised if you are breastfeeding. It may not be the best medication to use if you have liver, kidney, or lung problems. It should not be used with alcohol or other medications that depress the central nervous system (specially those that may affect the brain). People born with certain congenital disorders of metabolism should not use Topamax. If you have a history of depression, especially with thoughts of suicide, or a history of kidney stones (called nephrolithiasis), it should be used with caution. Caution is also advised if you have low potassium levels in the blood (hypokalemia) or metabolic acidosis, especially as part of diarrhea or dehydration from a hot environment. The medication may not be appropriate in those with epilepsy who are treated with a ketogenic diet and in status epilepticus. Further caution is advised in the setting of surgery.
What Are Common Side Effects?
As may happen with the use of any prescription drug, there is the potential risk for side effects when using Topamax. Although most people do not experience most or any of these side effects, some that may occur include:
- Slowed thinking (leading to the nickname "Dope-a-max")
- Fatigue or sleepiness
- Mood changes (depression, nervousness, or anxiety)
- Dizziness or unsteadiness (ataxia)
- Vision changes (including nystagmus and double vision)
- Weight loss, taste changes, or loss of appetite (anorexia)
- Hair loss (alopecia)
- Nausea, upset stomach, stomach pain, or diarrhea
- Decreased or altered sensation or tingling (paresthesia)
- Infection such as urinary tract infection (UTI) or sinusitis
- Metabolic acidosis
What Are Potential Serious Reactions?
There are also potentially serious side effects that may occur with the use of Topamax. These serious reactions occur more rarely. With the use of Topamax, some of the potential serious side effects include:
- Severe metabolic acidosis
- Kidney stones (nephrolithiasis)
- Bone density changes (osteomalacia or osteoporosis)
- Decreased sweating (oligohidrosis)
- Elevated body temperature (hyperthermia)
- Low potassium levels (hypokalemia)
- Hyperammonemic encephalopathy (manifest as confusion)
- Psychosis or suicidality
- Blood cell count changes (leukopenia or anemia)
- Vision problems including glaucoma, acute myopia, or maculopathy
- Severe skin reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme
- Growth suppression (in children)
- Neonatal cleft lip or palate (if used by pregnant women in the first trimester)
- Withdrawal seizures with abrupt discontinuation
What Safety Precautions and Monitoring Should Occur?
As described in detail above, there are certain people who should not use Topamax or who should use it only with caution. Topamax requires some blood tests, with creatinine and bicarbonate checked at baseline and then periodically. The medication may interact with other drugs, and all your medications should be carefully reviewed by your doctor and pharmacist to avoid potential problems. In addition, it is important to identify depression, behavior changes, and any thoughts of suicide as these may require discontinuation of the medication. Due to a risk of seizure, the medication should not be stopped abruptly without consultation with your physician.
If you experience any difficulties with the use of Topamax, you should be in close contact with your primary health care provider.
"Topamax." Epocrates Rx Pro. Version 5.1.2, 2013. Epocrates, Inc. San Mateo, California.