Metamizole is a powerful drug (active ingredient) for pain, cramps, and fever. Because of its mechanism of action and potential side effects, it requires not only a pharmacy prescription but also a prescription.
What is metamizole?
Metamizole is a powerful medicine (active ingredient) for pain, cramps, and fever. Metamizole is a medicine used to treat severe and moderate pain. It not only relieves pain per se, but in higher doses also has a spasmolytic (antispasmodic) and antipyretic (antipyretic) effect and is classified as one of the so-called pyrazolones. These also include drugs with the active ingredients phenazone, aminophenazone, propyphenazone and the phenylbutazone. All these drugs, with the exception of metamizole, belong to the NSAIDs. An analgesic is a drug that acts against pain. Antipyretics have an antipyretic effect. In addition, metamizole has the property that it also has an antispasmodic effect – but only in higher doses – and is therefore also a spasmolytic.
Pharmacologic action
As for the mechanism of action of metamizole, known in the drug trade mainly as novalgin, there is still no general agreement in medical research. First, it inhibits cyclooxigenases and thus prostaglandin synthesis. Prostaglandins are pain messengers. In addition, it has been researched that metamizole also has a central effect on neurons located in the thalamus and hypothalamus. This is said to have an effect on the general processing of pain, i.e. the sensation of pain, as well as on the regulation of body temperature. For this reason, metamizole, as the strongest analgesic that does not belong to the opioids and opiate derivatives, is used, for example, as a combination medication with tramadol for the analgesia of wound pain after surgery. It can also be combined with tilidine. The reason why it is often combined with opiates is that, according to a 2008 study by the University of Münster, metamizole, like opiates, acts on the NMDA receptor. This in turn increases the effect of morphine in combination with metamizole, although the actual opiate requirement is reduced. Among other things, this results in the significant advantage for patients who must be treated with a metamizole-opiate combination over a longer period of time that the time to the tolerance effect of the opiate is postponed, since less of the opiate is actually consumed than would be necessary without the metamizole to achieve substantial pain relief or absolute freedom from pain.
Medical application and use
As described above, metamizole is much more than a simple analgesic. It can do much more than simply relieve severe pain. It is used for chronic pain, in which case regular blood monitoring is necessary. It is also used for acute pain, for example colic of any origin, as it has a spasmolytic effect in addition to the analgesic effect. In cases of renal, biliary or intestinal colic, metamizole is usually preferred in emergency services and in doctors’ offices, since the use of opiates has often been observed to aggravate the symptoms. However, if the pain is not colic-like but injury or burn pain, metamizole is usually administered intravenously, possibly in combination with morphine, depending on the intensity of the pain and its genesis. Another important use of metamizole is when fever cannot be controlled with other common antipyretics from the group of NSAIDs such as ASA, acetaminophen, ibuprofen etc. There are patients who basically do not respond to these agents, or who cannot be treated with them due to intolerance of them, but still require fever reduction. In these cases, the fever rarely exists alone, but is accompanied by severe pain in various parts of the body. Metamizole thus kills two birds with one stone: high fever is lowered, which cannot be lowered with the other usual drugs, and the patient is relieved of the accompanying pain.
Risks and side effects
Metamizole, also known by the trade names Novalgin, Metamizol Hexal, Berlosin, etc., is basically a miracle drug in medicine. It can help reduce the need for opiates. It is a strong painkiller, relieves cramps and helps reduce fever.Nevertheless, like any other drug, it has the ability to cause effects that are not desired. In asthmatics, it can trigger threatening asthma attacks, from known as “analgesic asthma”. Anaphylactic reactions are also possible, such as shortness of breath, hives, etc. It can also cause dizzy spells and circulatory collapse by lowering blood pressure. The dreaded drop in blood pressure has been observed especially when intravenous injection is too rapid, and the administering physician should always be careful not to inject too quickly. If metamizole is used in the treatment of chronic pain, reliable blood monitoring must be performed at regular intervals, as long-term use can lead to so-called leukopenia. This is a dangerous reduction of white blood cells, also called leukocytes, which are necessary for the immune defense. If it is necessary to take metamizole, the rule of thumb is again: as much as necessary, as little as possible, in order to reduce the risks and side effects to a minimum.
