Topamax (topiramate) is a prescription anticonvulsant drug which is manufactured by Janssen Pharmaceuticals, a subsidiary of Johnson & Johnson. Topamax was approved by the U.S. Food and Drug Administration (FDA) in 1996 for the treatment of seizures in adults and later in children as young as 2 years of age. Use was expanded in 2004 for treatment of migraines in adults and adolescents.
Topamax grew to become a blockbuster drug and in 2008, Topamax controlled about 20% of the epilepsy market with sales peaking at $2.7 billion for the year but the medication lost patent protection in 2009 and sales of the brand name plummeted. Another form of topiramate, Qsymia has also been approved for weight loss in patients who are obese and suffer from at least one other medical condition such as diabetes or high blood pressure.
In 2010, Topamax manufacturers paid more than $80 million in fines and penalties for illegally marketing the drug. The companies also settled a number of Topamax lawsuits from women who claim that Topamax treatment caused their children to be born with debilitating birth defects.
What Is Topamax?
Topamax is the brand name of topiramate, manufactured by Janssen, a division of Johnson & Johnson. It is an anticonvulsant medication which is approved to treat certain types of seizures in adults and children over the age of two, and to prevent migraines in adults and adolescents over the age of 12. It can be used alone or with other anticonvulsant medications.
Epilepsy is a chronic brain disorder that causes uncontrollable brain activity or seizures. Topamax works by preventing brain cells from conducting excessive activity by blocking certain chemicals and pathways.
Topamax is used to treat seizures in adults and children over the age of two including:
- Partial-onset seizures
- Generalized tonic-clonic seizures
- Seizures associated with Lennox-Gastaut syndrome
Lennox-Gastaut syndrome is a type of epilepsy which causes multiple types of seizures, may cause seizure-related falls known as drop attacks and often results in developmental delay. It typically develops in early childhood, when a child is between the ages of three and five.
Migraine headache is a type of headache which is usually recurrent and causes moderate to severe pain which may be pulsing or throbbing, worsened by sound, light or movement, and may be accompanied by other symptoms such as nausea. Topamax helps to prevent migraine in the same way it may work for seizures and must be taken on a daily basis.
While Topamax helps many patients, it may also cause serious side effects such as eye damage, metabolic acidosis, and birth defects.
Topamax Side Effects
As with many other prescription drugs, Topamax may cause common side effects that range from mild to moderate and which may go away with time. It may also cause more severe side effects which can be serious, result in permanent injury or be life-threatening.
Common Topamax Side Effects
Most of the side effects caused by Topamax can be described as mild-to-moderate and will go away or lessen in severity as the patient becomes used to the medication.
Common side effects of Topamax include:
- Blurred or double vision
- Unsteadiness or clumsiness
- Dizziness or drowsiness
- Trouble with thinking and concentration
- Paresthesia (tingling, numbness, or other skin sensations)
- Unusual weight loss
- Taste change
- Appetite loss
- Infection of the upper respiratory tract
If side effects worsen in severity or become bothersome, they should be reported to a physician or health care practitioner.
Severe Topamax Side Effects
Topamax may also cause severe side effects which may be serious, result in permanent injury or be life-threatening. Serious side effects are defined as side effects which require hospitalization or medical treatment and/or result in permanent injury, birth defects or death.
Severe side effects of Topamax may include:
- Neurologic effects such as confusion, speech or language problems, changes of consciousness
- Oligohydrosis or decreased sweating which may lead to hyperthermia
- Eye problems including acute myopia, glaucoma, eye pain, headaches, blurred vision, blindness
- Increased risk of suicide
- Metabolic acidosis due to increased acid levels in body
- Birth defects including lung, skull and skeletal abnormalities
Topamax side effects include serious eye conditions that may lead to blindness. Acute myopia caused by Topamax use, may result in headaches and blurred vision due to increased pressure within the eye. Secondary angle closure glaucoma is another condition that may occur as a Topamax side effect and which may result in blindness. Patients should seek medical attention immediately if they experience pain or discomfort in the eyes.
A number of reports have indicated suicide as a Topamax side effect. Patients may experience suicidal thoughts and tendencies during use, particularly as medication is started or when dosage levels are changed. It is recommended that all patients are carefully monitored during treatment. Medical attention should be sought if the patient experiences symptoms such as anxiety, panic, onset or increased depression, or other significant changes in behavior or mood.
Metabolic acidosis is a Topamax side effect that results in an excessive amount of acid in the bloodstream. This is caused by acid production that occurs so rapidly that the kidneys cannot filter quickly enough. Severe metabolic acidosis can result in kidney damage, shock or death. Symptoms include rapid breathing, low blood pressure, lethargy, and confusion.
Topamax Birth Defects and Pregnancy-related Side Effects
Topamax side effects include severe birth defects if the medication is taken during pregnancy. The FDA listed Topamax in pregnancy category D, which indicate that harm to developing fetus has been proven. It is highly encouraged for pregnant women to avoid taking Topamax unless medically necessary and the benefits outweigh risks.
Topamax birth defects may include:
- Oral cleft abnormalities
- Persistent pulmonary hypertension of the newborn (PPHN)
- Malformation of limbs
- Heart and lung defects
- Spina bifida and other neural tube defects
Oral Cleft Deformities
A 2008 study showed that babies born during Topamax treatment were 16-times more likely to suffer birth defects. One primary Topamax birth defect is oral cleft abnormality, such as cleft lip and cleft palate. Cleft abnormality is an orofacial disorder that cause the skull’s plates to improperly fuse together, which results in an opening at the roof of the newborn’s mouth. In many cases, these malformations require multiple surgeries to correct
Persistent Pulmonary Hypertension of the Newborn
When taken during pregnancy, Topamax may also cause persistent pulmonary hypertension of the newborn (PPHN). PPHN constricts the arteries that lead to a newborn’s lungs which results in decreased blood flow to the lungs and lowered amounts of the amount of oxygen entering the bloodstream. Intubation and ventilation is often required to treat PPHN. It is estimated that up to 20 percent of infants with this condition do not survive.
Topamax FDA Warnings
Topamax initial prescribing information did not list many of the side effects which are now known to be serious or life-threatening, the FDA responded by issuing warnings and mandating that all topiramate labels and medication guides clearly state these warnings.
Metabolic Acidosis, Oligohydrosis, and Hyperthermia
The first Topamax FDA warning that was issued was in 2004 regarding increased risk of metabolic acidosis, oligohydrosis and hyperthermia. These conditions may result in medical emergency or may result in longer term injury to the patient.
Metabolic acidosis is an electrolyte Imbalance or increase in acid in the blood which may result in medical emergency or longer-term damage. Symptoms of metabolic acidosis include heartbeat irregularities, rapid breathing, and fatigue. Oligohydrosis is a decrease in sweating that can result in dangerous increase in body temperature or hyperthermia. Patients should seek treatment if experiencing these symptoms.
In 2006, the FDA issued a warning about the potential of developing eye disorders after using Topamax. These are thought to be caused by an allergic reaction to sulfa contained in the medication, which may cause fluid accumulation and swelling in the eyeball. Patients are urged to contact a doctor at the first sign of decreased vision or discomfort of the eyes, as conditions may worsen rapidly, and in rare cases permanent blindness has occurred.
Eye disorders from using Topamax:
- Glaucoma, or pressure that results in damage to the optic nerve of the eye
- Myopia, or nearsightedness
- Double vision or dry eyes
- Nystagmus or rapid eye movements
Development of Suicidal Thoughts and Actions
In 2008, an FDA warning was issued for increased risk of suicidal thoughts and actions in people taking Topamax and other antiepileptic drugs. In clinical trials, patients receiving an antiepileptic drug were twice as likely to have suicidal tendencies as those receiving the placebo.
Rather than adding a black box warning, the strongest warning put out by the Agency, the FDA added the warning to medication information and required manufacturers to develop and disperse a medication guide to warn patients of the dangers.
Birth Defect Warning
In 2011, the FDA issued a pregnancy birth defect warning for Topamax users after research showed women who took Topamax in their first trimester were 21 times more likely to have a baby with oral cleft defect than those who were not medicated. In addition, those who took Topamax were 3 times more likely to have oral defect than those taking other seizure medications.
In addition to oral defects, Topamax may also cause birth defects such as malformations of the lungs, heart, and limbs and neural tube defects such as spina bifida. Topamax was also downgraded from a Pregnancy Category “C” to “D”, which means that there is positive evidence of fetal risk, but the potential benefits of the drug may outweigh the risk in some situations.
Topamax may lower the effectiveness of certain birth control methods that utilize hormones. Patients should consult a doctor about effective forms of birth control while taking Topamax. If a patient becomes pregnant while taking Topamax, it may be dangerous to suddenly stop taking the drug, as the risk for recurring seizures is high.
Topamax Illegal Marketing
In April 2010, Topamax manufacturers agreed to pay more than $81 million for illegal marketing of Topamax as part of a settlement with the U.S. Department of Justice. Manufacturers admitted to marketing the drug for unapproved psychiatric uses under a program called Doctor-for-a-Day. Doctor-for-a-Day hired third party doctors to join the company’s sales representatives. Together, the doctors and representatives visited healthcare providers and spoke publicly about prescribing the drug for unapproved uses.
The FDA has approved Topamax for epilepsy conditions and migraines, but doctors may also give it to patients for other reasons as an “off-label” use. Topamax has been used off-label for problems such as alcohol dependency, bipolar disorder, drug addiction, and post-traumatic stress disorder but drug companies are not allowed to advertise or market the medication for unapproved uses.
Topamax Lawsuit Information
Janssen and parent company, Johnson & Johnson has faced numerous Topamax lawsuits which claimed injury due to use of the medication. These lawsuits alleged Topamax caused children to be born with birth defects and that Janssen Pharmaceuticals failed to adequately warn users of the danger caused by Topamax. Users claimed that patients had been warned of the dangers to their children, they would have been able to consider opting for other, safer epilepsy and migraine treatment.
In 2013, the first Topamax birth defect lawsuits went to trial and resulted in verdicts in the plaintiff’s favor with a $4 million judgement and a $11.7 million judgement in two separate trials. Both cases were appealed by the company, but judgements were upheld, and Johnson & Johnson agreed to settle 76 remaining cases in Philadelphia courts.
Notwithstanding claims relating to this product, the drug/medical device remains approved by the U.S. FDA.
- Topamax Prescribing Information, RxList (2020)
- Drug Makers to Pay Fine of $81 Million, New York Times (04/2010)
- FDA Drug Safety Communication: Risk of oral clefts in children born to mothers taking Topamax (topiramate), U.S. Food and Drug Administration (03/2011)
- Women Warned About Epilepsy Drug, New York Times(03/2011)
- $4 Million Awarded In 1st Pa. Trial Alleging Birth Defect From Topamax Epilepsy Drug, LexisNexis (10/2013)