Metamizole
Metamizole is a pyrazolone analgesic that relieves pain and lowers fever, acting largely through central mechanisms, and it also relaxes smooth muscle, which makes it useful in colicky or spasmodic pain. Unlike the classic anti-inflammatory drugs it has little effect on inflamed tissue itself. Its regulatory status varies between countries. It is used for pain, fever and spasm.
It may be taken with or without food. Its defining risk is idiosyncratic rather than dose-related: metamizole can suppress the bone marrow's production of white blood cells, and agranulocytosis may appear at any point in a course, which is why treatment is kept short and why white cell count and absolute neutrophils are the markers followed. There is no way to feel this happening; the first sign is usually an infection that the depleted defences cannot contain.
A sore throat, mouth or genital ulcers, fever or chills during a course must be reported and mean see a doctor promptly for a blood count. Marked weakness, a rash, or a sudden drop in blood pressure with faintness also call for medical assessment.
Reference information, not medical advice. Discuss any change with your doctor.