Toxicities

Below are listed some incidences of toxicities related to off-label drug use by brain tumor patients. Page still under construction.

Chloroquine phosphate

The main risk of long-term chloroquine use is retinal damage. One study concludes that “The risk of developing toxic retinal chloroquine damage seems to be small or absent even in long term treatment, providing the dose is kept low, not higher than 0.25 g [250 mg chloroquine phosphate] daily for 10 months annually, and the patient is under 50 years old and does not suffer from any other illness which might affect the retina. The total annual dose is thus 70-75 g. Regular ophthalmological checks should then not be essential. In elderly patients, over 50-60, in whom there is the problem of differentiating senile maculopathy from chloroquine-induced maculopathy, regular ophthalmological check-ups are advised.”

Dichloroacetate (DCA)

Case 1:

Reported on the Brain Tumor Treatments yahoo group: one woman took DCA at a dose of 12 mg/kg divided into two equal doses daily, 2 weeks on, one week off, for 5 months.  In addition to DCA, the woman took 125 mg vitamin B1, Celebrex, metformin and omeprazole every day.  At 3 months, symptoms of peripheral neuropathy appeared, and by the end of 5 months she had complete numbness in toes, and nearly complete numbness in fingers.  6 weeks after stopping DCA, there was very little improvement in the neuropathy.

Case 2:

Reported to me by email, a young man about 30 years old began taking DCA as a treatment for a secondary IDH-mutant glioblastoma following a second resection.  Total time on DCA was 6 or 7 weeks. At first the daily dose was 5 mg/kg twice daily, which was increased to 10 mg/kg twice daily after a few weeks.  DCA was discontinued due to trembling hands and extreme fatigue. Peripheral neuropathy in hands and feet became apparent in the weeks immediately after discontinuing DCA, and persisted for at least a month.

Medicor Cancer Centre:

As of 2010, Medicor Cancer Centres in Toronto was supplementing DCA therapy with benfotiamine (a vitamin B1 analog, dose of 80 mg orally twice daily), R-alpha lipoic acid (dose of 150 mg orally, three times daily) and acetyl L-carnitine (dose of 500 mg orally, three times daily).  These supplements were given with the intention of limiting side-effects of DCA, such as peripheral neuropathy, sedation, confusion, memory problems, mood changes, hand tremors.

See the Drug Dosing page for information on DCA dosing.

Disulfiram (Antabuse)

After approximately 3 months taking 250mg of disulfiram once daily, one man began to experience "pins and needles" due to peripheral neuropathy in his feet, which progressively worsened.  Disulfiram was stopped after six months of use due to these symptoms, and it took about a year to regain full sensation in his feet.