Ziconotide (Prialt, SNX-111)

• synthetic derivative of ω-conotoxin M-VII-A, a peptide toxin produced by Conus magus, a species of cone snail
  
• cone snails are way cool: they use a venomous harpoon to catch fish AND they have rad looking shells
  
• used to alleviate severe chronic pain but is neither an opioid nor a NSAID, these being the two main classes of analgesics (painkillers)
• unlike opioids does not appear to be addictive (no tolerance or dependence) or cause respiratory depression
  
• used only when all other possible therapy options have been exhausted, including injecting morphine directly into the spine, since it must be injected directly into the cerebrospinal fluid (CSF) within the spinal cord to work (this is pretty darn invasive and so kinda risky)
• can't be given orally since it is a peptide and so is broken down by the stomach
• can't be given intravenously since it causes profound systemic side effects (it is derived from an incredibly badass toxin, after all!)
  
• does its thing by blocking N-type calcium channels, a variety of voltage-gated calcium channel found primarily in neurons, disrupting calcium-dependent transmission of pain signals via the spinal cord to the brain
  
• N-type calcium channel blockers (NCCBs) represent an exciting new class of neurological analgesic drugs
  

Klotz U. Ziconotide--a novel neuron-specific calcium channel blocker for the intrathecal treatment of severe chronic pain--a short review. Int J Clin Pharmacol Ther. 2006 Oct;44(10):478-83.