[5][6] This action inhibits the release of pro-nociceptive neurochemicals like glutamate, calcitonin gene-related peptide (CGRP), and substance P in the brain and spinal cord, resulting in pain relief.

[6] Due to the profound side effects or lack of efficacy when delivered through more common routes, such as orally or intravenously, ziconotide must be administered intrathecally (i.e., directly into the spinal fluid).

[9][10] However, this must be weighed against the high level of pain management, both in terms of degree and length, and the apparent lack of tolerance[11] and other signs of dependence[12] even after extended treatment along with the need for alternatives to other therapies that have not worked for the patient.

Others may include weakness, hypertonia, ataxia, abnormal vision, anorexia, somnolence, unsteadiness on feet, vertigo, urinary retention, pruritus, increased sweating, diarrhea, nausea, vomiting, asthenia, fever, rigors, sinusitis, muscle spasms, myalgia, insomnia, anxiety, amnesia, 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 kidney failure, atrial fibrillation, cardiovascular accident, sepsis, new or worsening depression, paranoia, disorientation, meningitis, and seizures.