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Topamax Side Effects

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Serious side effects associated with Topamax include an increased risk of suicidal thoughts or behavior, hyperthermia, glaucoma and neurological problems. It can also cause birth defects if taken by pregnant women.

Topamax (topiramate) is an anticonvulsant medication approved by the Food and Drug Administration (FDA) in 1996 for use in the treatment of epilepsy, and in 2004 for the prevention of migraine headaches. Unfortunately for its millions of users, Topamax and its active ingredient, topiramate, is associated with many severe health hazards and serious side effects.

Although the medication does not contain a black-box warning on its label (the FDA’s most stringent), the list of warnings and precautions on its Medication Guide is extensive, having been updated continually since the drug’s introduction into the marketplace. These updates have been mandated by the FDA over the years, as post-market studies continued to confirm Topamax’s adverse health effects.

Common and Serious Side Effects of Topamax

Janssen Pharmaceuticals maintains that Topamax is safe when used as indicated and originally only warned consumers of its more common side effects, considered by the company to be “mild to moderate.”

They include:
Fatigue Loss of appetite
Nausea Taste change
Weight loss Nervousness
Diarrhea Upper respiratory tract infection
Tingling in the arms and legs (paresthesia)

However, topiramate has also been associated with the following more serious side effects:

  • Acute Myopia and Secondary Angle Closure Glaucoma – the symptoms of these serious eye problems can include acute onset of decreased visual acuity and/or ocular pain. Both conditions can cause permanent blindness if left untreated.
  • Hyperthermia and Oligohydrosis – increased body temperature caused by decreased sweating can lead to hospitalization.
  • Metabolic Acidosis – occurs when the body produces too much acid, or the kidneys do not remove enough acid from the body. Metabolic acidosis can cause brittle or soft bones, kidney stones, can slow the rate of growth in children, and can result in coma and death.
  • Suicide – Topamax can increase the risk of suicidal thoughts or behavior. Users should be monitored for the emergence or worsening of depression, increased anxiety or panic, and/or any unusual changes in mood or behavior.
  • Cognitive/Neuropsychiatric Adverse Reactions – these dysfunctions include confusion, psychomotor slowing, difficulty with concentration and memory, and speech or language problems.
  • Hyperammonemia – high blood ammonia levels can affect mental activities, slow alertness and cause fatigue or vomiting.

Topamax and Birth Defects

Perhaps the most deleterious side effect of Topamax is its potential toxicity to fetuses. Infants exposed to topiramate in utero have an increased risk for cleft lip and cleft palate, especially if the drug is taken during the first trimester of pregnancy.

A cleft palate is a type of orofacial disorder that results in an opening in the roof of the mouth when the two plates of the skull do not fuse together properly. A cleft lip may also occur in combination with a cleft palate. Multiple surgeries may be required to reconstruct the malformed tissues.

In July 2008, a study in Neurology revealed that babies born to mothers who took Topamax during pregnancy suffered birth defects at 16 times the average rate. And data from the North American Antiepileptic Drug (NAAED) Pregnancy Registry show that the prevalence of oral clefts was 1.4 percent when mothers took Topamax during pregnancy, compared with a rate of 0.38 – 0.55 percent in infants exposed to other antiepileptic drugs (AEDs), and 0.07 percent in infants of mothers without epilepsy.

In March 2011, the FDA issued a warning that Topamax may increase the risk of oral cleft birth defects, pointing to the Neurology study and NAAED data. The FDA also reclassified Topamax as a Class D drug, meaning it has been shown to harm the human fetus. Topamax lawsuits claim the manufacturer should have fully informed women of the risk of birth defects.

Babies born to mothers who took Topamax also may suffer from other birth defects, including:
Persistent pulmonary hypertension of the newborn (PPHN) Limb malformations
Heart defects Lung defects
Neural tube defects, including spina bifida