Colorectal cancer patients getting oxaliplatin quickly learn to avoid cold. Drinks with ice, chilly air, even opening the freezer can produce sudden, sharp pain, burning, or an unpleasant pins and needle feeling in their throat and hands.

A small study has found that venlafaxine (Effexor) can completely eliminate acute neurotoxicity from oxaliplatin in about 1 out of 3 people.  More than half of patients who took it had more than 50 percent relief from symptoms.

In the trial, 48 patients who were already having pain after oxaliplatin infusions were randomly assigned to get 50 mg of immediate release venlafaxine an hour before their treatment or a placebo.  They then took an extended release venlafaxine capsule or a placebo twice a day for the next ten days, stopping the medicine two days before their next oxaliplatin treatment.

They rated their symptoms on the day of treatment and four days after it using the Neuropathic Pain Symptom Inventory (NPSI), a scale that rates 12 neurosensory feelings (for instance, burning pain, pins and needles,pain made worse by cold,pain like electric shocks, pain that is worse when something touches you).  They also reported changes in function — how well they could use their hands or feet.

Results

• 31.3 percent of patients taking venlafaxine had complete relief of symptoms compared to 5.3 percent of those on placebo.
• 58.8 percent of patients had some relief, at least 50 percent, of symptoms compared to 26.3 percent of those taking a placebo.
• None on venlafaxine had grade 3 acute neuropathy with serious pain, loss of feeling, or loss of function while 33.3 percent of those on placebo did.

Venlafaxine also improved problems with pins and needles and functioning.

There were no serious side effects for those taking the medicine.  The most common side effects were mild to moderate feelings of general weakness and nausea.

While the study showed that venlafaxine may be helpful in reducing acute neurotoxicity from oxaliplatin, it was small.  Larger trials are necessary before its safety and effectiveness can be reliably demonstrated.

Effexor® (venlafaxine) is approved by the FDA to treat depression and anxiety disorders.  While it is sometimes used off-label to treat other conditions, including diabetic neuropathy, it is not approved for acute neuropathy from oxaliplatin treatment.  Like other anti-depressants that are similar to it, it carries a warning box on its label for risk of suicidal feelings.  It may interact with a number of prescription medicines as well as some herbal products, including St. John’s Wort.

SOURCE: Durand et al., Annals of Oncology, Advance Access, March 22, 2011.