What is Ziconotide?Ziconotide is an analgesic. The remedy is used to treat severe chronic pain. Ziconotide is administered using an intrathecal catheter.
The active ingredient ziconotide is understood to mean a polypeptide which is used as a painkiller under the trade name Prialt®. The remedy originally came from the venom of the marine snail Conus magus. However, medicine uses a synthetic replica of the natural substance.
Ziconotid entered the market in 2001 for the treatment of rare conditions. Since 2005, the active substance has been approved under the name Prialt in Europe. In its early stages, ziconotide was considered as a possible replacement for morphine. Since 2010, however, the drug is under discussion, due to a higher risk of suicide, which refers to several individual cases.
Ziconotide is not an opioid and does not interact with opiate receptors. Instead, the effect of the amino acid peptide is that it acts as an antagonist to N-type calcium channels that are voltage dependent. These occur in high density in special neuronal cells within the spinal cord posterior horn.
At these sites, the NCCB channels, as they are called, regulate the release of messengers that contribute to the processing of pain. By binding the calcium channels, ziconotide can curb the influx of calcium towards nociceptive afferent nerves. Due to the blockade of the N-type calcium channels, the transmission of the pain signals is finally interrupted. In addition, ziconotide has a neuroprotective effect.
From a chemical point of view, Ziconotid is the omega-conopeptide MVIIA. It is a small protein molecule made up of 25 amino acids. To take in tablet form, the drug is not suitable because it would come in the gastrointestinal area for cleavage of the protein molecule by the digestive enzymes. Therefore Ziconotid could not reach the target location in the spinal cord.
For this reason, the active ingredient is supplied to the body exclusively by continuous infusion into the spinal canal. The agent is used as an acetate via a mechanical pain pump. A combination of ziconotide and relaxants with central action, local anesthetics and opioids is also possible.
Medical application & use
Although ziconotide is a non-opioid analgesic, it is suitable for the treatment of severe chronic pain. However, the administration is limited to people who require intrathecal anesthesia. In this procedure, the analgesic is administered directly into the spinal canal, which passes through multiple vertebrae.
In most cases, patients are affected by a ziconotide therapy in which opioid preparations are inadequate or intolerable for treatment. Unlike other non-opioid analgesics, Ziconotide is also suitable for the treatment of severe pain.
Ziconotide is administered using an intrathecal catheter. It is important to store the medicine at temperatures between 2 and 8 degrees Celsius, whereby it must not be exposed to minus temperatures. In addition, the preparation must be protected from light.
The dose of ziconotide is 2.4 μg per day at the start of treatment. In the further course, the dosage increases to the required level. The recommended maximum amount reaches 21.6 μg per day. In most cases, a dose of 9.6 μg is considered sufficient.
Risks & Side Effects
The use of Ziconotide may be associated with various side effects. Weakness, nausea, vomiting, gait disturbances, blurred vision and confusion are particularly common. Not infrequently, there are also unwanted side effects such as loss of appetite, sleep problems, mood swings, nervousness, seeing double images, hearing sounds, anxiety, thought disorders, paranoia, urinary incontinence, urinary retention, muscle pain, water retention in the body tissue, chest pain, feelings of Cold, loss of weight, difficulty in breathing, heavy sweating, itching, low blood pressure, dry mouth, tinnitus, fever and depression.
Other possible side effects, which are rare, include unconsciousness, walking problems, skin rashes, neck pain, back problems, increased body temperature, convulsions, acute kidney failure or meningitis (meningitis). Even a stroke and blood poisoning are in the range of the possible.
It is believed that there is a link between taking ziconotide and suicide attempts. Therefore, a thorough examination of the physician should be made in advance of treatment. Similarly, consistent monitoring by relatives is recommended.
If the patient suffers from hypersensitivity to ziconotide, the active substance should not be used. Also a combination with chemotherapeutics is foreseeable. These are cancer drugs and various antibiotics, as long as they are also administered via the spinal canal.
Use of the product during pregnancy and lactation is not recommended. Although there are no studies in humans on the risks during this period, animal experiments have had adverse effects on offspring. Whether the use of Ziconotide in children makes sense, decides the doctor. There are no such studies yet.
The concomitant use of ziconotide and certain other medicines may result in harmful interactions. For example, drugs such as the antihypertensive drug clonidine, the local anesthetic bupivacaine, the anesthetic propofol or the muscle relaxant baclofen may cause drowsiness when coadministered with ziconotide.
Caution should be exercised when combining the analgesic with morphine. Even at low doses of Ziconotide, severe side effects such as gait disturbances, confusion and delusions were common. In addition, patients often suffered from appetite disorders and vomiting.