Ziconotide: Indications, adverse effects, and limitations in managing refractory chronic pain

When administered systemically, ziconotide has limited penetration across blood-brain barrier at the cost of unbearable side effects.[...]it is administered intrathecally to patients for better penetration across blood-brain barrier, better analgesia, and lesser side effects.[...]adverse events are frequently noted with its use which interrupts the ongoing treatment.The commonly encountered adverse effects are cognitive and neuropsychiatric (confusion, memory impairment, and hallucinations), presyncopal and syncopal episodes, gait disturbances, meningitis, depression, and elevated creatine kinase.