Pfizer Inc. is facing a Dilantin (phenytoin) lawsuit, which alleges the antiepileptic drug had caused two patients to develop cerebellar atrophy.

The lawsuit was reportedly jointly filed by a man and woman from Arizona, with their claim alleging Pfizer Inc. failed to warn them against the alleged correlation between the anticonvulsant drug and permanent brain damage.

Plaintiffs Meredith T. and Roger W. were reportedly prescribed Dilantin for typical treatment purposes and had used this medication for decades without concern for serious side effects.

It was only recently that the claimants learned of the alleged correlation between Dilantin and cerebellar atrophy, which was not mentioned on the drug’s warning label.

According to the Dilantin lawsuit, Meredith had suffered from seizures through most of her life and has been on Dilantin for several decades.

The medication reportedly caused Meredith to develop cerebellar atrophy, which causes her a multitude of problems including memory loss, vision problems, gait disturbances. These problems have reportedly caused Meredith to require a live-in caretaker to assist her with everyday activities.

Similarly, Roger says he was prescribed Dilantin for several decades to help manage his seizures. However, Roger allegedly developed cerebellar atrophy due to phenytoin toxicity and now suffers from a number of difficulties including memory loss, gait disturbances, and difficulty balancing.

Both Meredith and Roger allege they will suffer from the effects of this disease for the rest of their lives.

Overview of Dilantin Toxicity

Phenytoin has been on the market for over 100 years and is one of the oldest and most frequently prescribed anticonvulsants in the United States.

This antiepileptic drug works by slowing down the electrical signal in the brain, which helps prevent the onset of seizures. Even though Dilantin has helped millions of patients with epileptic conditions, it has become associated with cerebellar atrophy.

Also known as focal cerebral atrophy, this disease deteriorates the cerebellum and the patient’s overall ability to move and talk. The cerebellum sits behind the brain stem and is primarily responsible for the patient’s ability to coordinate voluntary actions like walking and talking.

This means that when the cerebellum is damaged, the patient’s quality of life will be severely impacted, with symptoms including:

• Uncoordinated Walking Gait
• Back and Forth Tremors
• Uncoordinated Movements in Arms and Legs
• Slow or Slurred Speech
• Swallowing
• Nystagmus (small rapid eye movements)

Patients are recommended to see a doctor when they have trouble keeping their balance, losing muscle coordination in their arms and legs, and any difficulties in walking or talking.

These symptoms are caused by the fact that cerebellar atrophy affects the nervous system, which means the communication between the brain and spine is directly impacted. Oftentimes physical therapy or drugs can be prescribed to treat the symptoms, with recommendations varying between patients.

According to the Mayo Clinic, potential causes of cerebellar atrophy also include other degenerative diseases like multiple sclerosis and Alzheimer’s or physical injuries like head trauma. Other risk factors include drugs and alcohol, or other activities that could induce reduced brain function.

It is important to note that there is currently no cure for cerebellar atrophy, so Dilantin patients should see their doctor immediately if they experience any difficulties in talking or moving.

Overview of Dilantin Cerebellar Atrophy Correlation

While there are a number of potential causes of cerebellar atrophy, phenytoin toxicity has been associated with the disease since the early 1990s.

Researchers reportedly became concerned over an alleged correlation in 1994, when they noticed phenytoin patients had significantly smaller cerebelli compared to nonexposed patients in diagnostic brain scans. Ever since then, there have been multiple studies supporting these findings.

One case study observed the case of a 16-year-old boy, who was reportedly not diagnosed with cerebellar atrophy until after 10 years of taking phenytoin. According to the study, the disease was discovered when the patient was seeing a doctor for a viral fever and mentioned he had difficulty walking.

Doctors reportedly noted the boy had unusual eye movements and unusual limb tremors, with a diagnostic image test reportedly confirming the boy was suffering from severe cerebellar atrophy.

The doctors’ analysis reportedly indicated a potential connection between phenytoin and cerebellar atrophy. After the boy was taken off the antiepileptic drug, but the damage was already done.

The authors of the study recommended that long term phenytoin patients should undergo regular blood plasma monitoring, to ensure that the doses are within a reasonable range.

While any exposure to phenytoin can raise the risk of cerebellar atrophy development, studies have found the diagnosis is more likely in long term exposure patients or patients with larger phenytoin prescriptions. Another study published in 1997 had observed a patient who had a history of tonic-clonic seizures and had been prescribed phenytoin.

He was prescribed double the daily dose of the drug after suffering two generalized seizures. However, the patient reportedly developed double vision and moving difficulty soon after the double dose prescription was started.

After being admitted to the hospital, he was accidentally exposed to double the dose of his already high prescription due to communication issues between his doctors and family members, who were unknowingly giving him the medication simultaneously. During this time, his symptoms reportedly worsened.

By the time he checked into a different hospital, his phenytoin levels were already four times the maximum therapeutic level. Diagnostic images revealed severe physical changes in his brain, including cerebellar atrophy.

While his symptoms eventually improved enough for discharge, the patient still had problems walking, and suffered from impaired memory and calculation.

Six months later, more image studies showed that his condition had turned severe and the patient was finding it increasingly difficult to move. He was eventually at the point whether he could only walk a few steps without support.

The researchers in this study reportedly concluded that the patient’s cerebellar atrophy and other symptoms were due to the phenytoin overdose, which prompted them to theorize that phenytoin toxicity could cause damage to the cerebellum.

According to the Dilantin lawsuit, the treatment mechanism of Dilantin reportedly involves increasing gamma-aminobutyric acid (GABA) concentration in the brain. GABA is an important neurotransmitter in the cerebellum and is the pathway phenytoin utilizes to control seizures.

However, repeated doses of phenytoin patients could overstimulate Purkinje cells, which increases the rates of firing cerebellar neurons. This overexertion of cerebral activity may be a contributing factor in phenytoin toxicity causing cerebellar atrophy.

There have been several other studies that have linked Dilantin to cerebellar atrophy, including one 2004 inquiries that examined multiple patients. Each of these patients was reportedly prescribed phenytoin for typical treatment purposes, with researchers following them during the course of their prescriptions.

According to the study, each patient had high phenytoin plasma levels and none were having seizures that could have been linked to cerebellar atrophy. However, the disease was reportedly diagnosed through CT scan in at least several subjects after they continued to experience symptoms.

The study suggested that long term phenytoin prescriptions increased the risk of cerebellar deterioration, but also stated that having multiple seizures can also contribute to causing cerebellar atrophy.

In addition, it has been suggested that pediatric patients may also be at risk for the dangers of cerebellar atrophy. Overall, these studies highlight the devastation and permanence this disease causes.

Patients suffering from cerebellar atrophy oftentimes have difficulty performing daily tasks on their own such as walking, eating, driving, and other chores that require hand-eye coordination.

Even though cerebellar atrophy is a very serious condition, it is reportedly not mentioned on Dilantin’s warning label.

Overview of Pfizer’s Negligence

Pfizer has been reportedly aware of the alleged correlation between Dilantin and cerebellar atrophy but failed to warn the general public. At all times relevant, Meredith and Roger allege they used Dilantin for its intended purpose and did not deviate from prescription instructions.

During their prescriptions, Meredith, Roger, and their physicians say they relied on the product information provided by Pfizer Inc. Given that both claimants used the anticonvulsant for decades, their phenytoin exposure was high and they were using the drug when the previously mentioned studies and other inquiries were published.

Each of the studies reportedly indicated a correlation between phenytoin and cerebellar atrophy. Even though Pfizer was reportedly aware of these studies, the company still did not contact the medical community or make any public disclosures about the alleged link.

Meredith and Roger’s lawsuit alleges these actions prevented them from making an informed medical decision, and the anticonvulsant presented unreasonable risks for patients.

Had this information been available, this would have allegedly impacted Meredith and Roger’s decision in continuing their Dilantin prescriptions. Overall, the Dilantin lawsuit alleges Pfizer failed to inform its consumers of all potential side effects of their product.

Meredith and Roger are seeking damages in their Dilantin lawsuit for negligence and failure to warn. The damages would compensate Meredith and Roger past and future medical expenses, along with any other financial burdens that may have incurred due to cerebellar atrophy.

Dilantin patients who are considering filing legal action against Pfizer should document any damages, financial or otherwise, which may have incurred due to their illness.

This includes hospital bills, doctor’s notes, prescriptions, medical equipment purchases like walkers or wheelchairs, or other medical expenses like hiring a live-in nurse.

Overall, patients should document all interactions pertaining to cerebellar atrophy including any expenses from their medical insurance.

This Dilantin Lawsuit is Case No. 2:19-cv-02853-DLR, in the Superior Court of Arizona, Maricopa County.