Cancer Pain
Trying to discover how doctors might treat severe chronic cancer pain, I came across a new experimental drug called Ziconotide. It might hold developmental promise. It is given intrathecaly (spine). Ziconotide is a conotoxin and calcium channel blocker derived from sea snails. It is non addicting, has no build up tolerance, but does have many many side effects which are not reversible. Kidney shut down is one side effect.
It can only be given intrathecal; there is no tolerance, no dependence. Ziconotide is contraindicated in patients with certain preexisting mental disorders (e.g. psychosis) due to evidence that they are more susceptible to certain severe side effects.Adverse Effects
The most common side effects are dizziness, nausea, confusion, nystagmus and headache. Others may include weakness, hypertonia, ataxia, abnormal vision, anorexia, somnolence, unsteadiness on feet, vertigo, urinary retention, pruritis, increased sweating, diarrhea, nausea, vomiting, asthenia, pyrexia, rigors, sinusitis, muscle spasms, myalgia, insomnia, anxiety, amnesia, nystagmus, tremor, memory impairment and induced psychiatric disorders. Other side effects which are less frequent but still clinically significant include auditory and visual hallucinations, thoughts of suicide, acute renal failure, atrial fibrilation, cardiovascular accident, sepsis, new or worsening depression, paranoia, disorientation, meningitis and seizures. Therefore, it is contraindicated in people with a history of psychosis, schizophrenia, clinical depression, and bipolar disorder. Recent incidents suggesting a link between intrathecal ziconotide treatment and increased risk of suicide have led to calls for strict and ongoing psychiatric monitoring of patients to avoid suicide occurring in vulnerable individuals. There is no known antidote. Some patients who received Ziconotide therapy and suffered intolerable adverse side effects continue to suffer from these same side effects many years after discontinuation of the drug therapy in the form of "flash-backs". These "flash-backs" are equivalent in intensity to those suffered while receiving the ziconotide therapy. Weight loss and the subsequent break down of fat cells seems to trigger "flash-backs".
