What to avoid with HNPP

An interesting discussion emerged on one of the HNPP groups about how certain products can actually have a reverse effect on the nerves. While there are hundreds of results when it comes to what to eat or how to help neuropathic symptoms, it’s rather a different situation when you attempt to search foods, supplements or drugs to be cautious about. So what should we keep an eye on?

Disclaimer: Please ask your medical practitioner or occupational therapist for more information. This article is based on various research, journals and testimonies.

Vitamin C

This a hot topic of debate with some saying that high doses of vitamin C can actually reduce the amount of PMP22 produced, while others saying they have seen some benefits through increased energy. So what’s the deal?

While there is little research to show the effects of vitamin C on HNPP specifically, there has been studies revealing how it affects the inherited condition Charcot Marie-tooth syndrome.

In the 2004 study Ascorbic Acid Treatment Corrects the Phenotype of a Mouse Model of Charcot-Marie-Tooth Disease, the authors claimed to see an improvement from ascorbic acid (vitamin C). They say: “Ascorbic acid treatment resulted in substantial amelioration of the CMT-1A phenotype, and reduced the expression of PMP22 to a level below what is necessary to induce the disease phenotype.

“As ascorbic acid has already been approved by the FDA [Federal Drug Administration] for other clinical indications, it offers an immediate therapeutic possibility for patients with the disease.”

While the authors saw benefits by reducing the expression of PMP22, it may be difficult to say whether this will have a reverse effect for those with HNPP, which consists of already having a deletion or defection of one of two of these genes.

On the other hand, a study of 277 persons with CMT1A found no significant effect of a daily 1.5-g dose of ascorbic acid after two years. The researchers of the 2011 study Ascorbic Acid in Charcot–Marie–Tooth disease type 1A states: “With respect to the size of the effect of ascorbic acid, if the effect is so small that only a biomarker can detect it, it would be unlikely to be clinically significant in a short-term study but might be important in the long term.

“Findings of this study suggest that ascorbic acid is not efficacious in adults with CMT1A.”

As with any supplements, it’s important not to take an excessive amount. As Thomas Bird, MD, writing for GeneReviews, a genetic resource page for clinicians, states: “No specific treatment for the underlying genetic or biochemical defect exists and no special diet or vitamin regimen is known to alter the natural course of HNPP.”

Always check with your medical practitioner about possible effects and let them know about your condition.

Vincristine 

Vincristine is a known chemotherapy drug used to treat several types of cancer including acute leukaemia, malignant lymphomas and carcinomas. If you’re suffering from multiple illnesses, this is where it gets complicated.

The medication is said to be potentially “toxic” to those with peripheral neuropathy due to its side effects that resemble the same symptoms. These can include numbness, pin prick or a tingling sensation to full-blown motor difficulties and neuritic pain.

In one study, 61 per cent of the 23 patients treated for lymphoma developed neuropathy, while only 14 per cent of the 37 patients with other malignant diseases developed these symptoms.

There has also been a case report of a patient with a familial variant of Charcot-Marie-Tooth syndrome. After receiving two 2mg dosages, his weakness secondary to peripheral neuropathy rapidly progressed to complete paraplegia. Acute acoustic nerve palsy has also been reported.

Hence letting your medical team know about the condition that you have and how you are affected can help avert a crisis such as this.

Taxol

Paclitaxel, sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, breast cancer, lung cancer, Kaposi sarcoma, cervical cancer, and pancreatic cancer.

Drugs and medications such as taxol that are known to cause nerve damage should be avoided, says Vinay Chaudry, MD, in a 2003 study Toxic Neuropathy in Patients With Pre-Existing Neuropathy. Chaudry says that six patients with pre-existing neuropathy, who received “non-toxic” dosages of known neurotoxic agents including taxol, had significantly worsened. He concludes: “functionally disabling toxic neuropathy can occur in patients with pre-existing neuropathy at standard doses.”

The Charcot-Marie-Tooth Association has maintained a “Medical Alert” list of potentially neurotoxic medications. They define taxol as a “definite high risk” to those with the condition even if the individual may not present any symptoms.

Fluoroquinolones

The fluoroquinolones are a family of broad spectrum, systemic antibacterial agents that have been used widely as therapy of respiratory and urinary tract infections. It is an antibiotic used to treat some infectious or even common diseases.

However, in 2016, the U.S. Food and Drug Administration advised that the serious side effects associated with fluoroquinolone antibacterial drugs generally outweigh the benefits for patients with neuropathic issues.

“The peripheral neuropathy reported with fluoroquinolone administration can be severe, debilitating, and permanent.”

A Case Report on a Rare but Serious Debilitating Side-Effect of Fluoroquinolone Administration – Jacquelyn K. Francis and Elizabeth Higgins, MD, 2014.

In a statement, the FDA said: “An FDA safety review has shown that fluoroquinolones when used systemically (i.e. tablets, capsules, and injectable) are associated with disabling and potentially permanent serious side effects that can occur together. These side effects can involve the tendons, muscles, joints, nerves, and central nervous system.”

In one 2014 case report for the Journal of Investigative Medicine, a 57-year-old woman was treated for a urinary tract infection with a ciprofloxacin, an antibiotic under the fluoroquinolones umbrella. She had already been in remission for 12 years after suffering from trigeminal neuralgia. Two years after the initial onset of symptoms, she continued to suffer from polyneuropathies chronologically related to ciprofloxacin use.

As the report concludes: “the peripheral neuropathy reported with fluoroquinolone administration can be severe, debilitating, and permanent. It is for this reason that physicians need to practice due diligence when prescribing not only antibiotics, but any drug.”

While it’s important to understand how the wrong drugs can interact with hereditary neuropathy, it’s even more essential to talk about it with the right people. Letting health professionals know about your current situation will allow them to prescribe the right medication. As one HNPP’er says because there’s an assumption that something is safe, doesn’t mean it’s safe for us.