Novalgin

Indications

Metamizol (also called dipyrone or metamizole sodium) is used for severe or stubborn pain, such as pain after injury or surgery, colicky pain from spasm of the gut, bile ducts or urinary tract (for example kidney stone pain), and cancer pain. It is also used for high fever that does not respond to other measures.

How It Works

Metamizol is a non-opioid pain reliever and fever reducer. It reduces the production of prostaglandins, chemicals that cause pain and fever, mainly in the brain and spinal cord, and it also acts on pain pathways. It has a mild relaxing effect on smooth muscle, which helps colicky pain. It has only weak anti-inflammatory action and is gentler on the stomach than many NSAIDs.

Dosage and Administration

Use only as prescribed, at the lowest effective dose for the shortest time. The usual adult dose by mouth is 500 mg to 1 g up to 4 times a day, with a maximum of 4 g a day. Swallow tablets with water. Injections are given slowly by a doctor or nurse, as prescribed, with the patient lying down. Children's doses depend on body weight and are given as prescribed; it is not used in babies under 3 months.

Interactions

• It can lower blood levels of Ciclosporin, Bupropion, Efavirenz and some other medicines.
• With Methotrexate it increases the risk of blood problems.
• It may reduce the heart-protecting effect of low-dose Aspirin; take Aspirin at least 30 minutes before metamizol.
• Chlorpromazine with metamizol can cause a severe drop in body temperature.
• Alcohol should be avoided.

Contraindications

• Allergy to metamizol or other pyrazolone medicines (such as Propyphenazone or Phenylbutazone).
• History of agranulocytosis (a dangerous drop in white blood cells) or bone marrow problems.
• Asthma or allergic reactions triggered by painkillers (analgesic asthma).
• Acute hepatic porphyria or glucose-6-phosphate dehydrogenase (G6PD) deficiency.
• Last 3 months of pregnancy, and babies under 3 months.

Side Effects

Possible effects include low blood pressure (especially with injections), skin rash, nausea and red-coloured urine (harmless). Rare but serious effects include agranulocytosis, severe allergic reactions and severe skin reactions.

Stop the medicine and get urgent medical help if you have fever, chills, sore throat, mouth ulcers or painful swallowing (possible signs of very low white cells), swelling of the face or throat, difficulty breathing, fainting, blistering or peeling skin, or yellowing of the skin or eyes.

Pregnancy and Lactation

Avoid in the first 3 months of pregnancy unless the doctor considers it necessary, and do not use in the last 3 months, as it may affect the baby's heart and kidneys. Breakdown products pass into breast milk; avoid breastfeeding for 48 hours after a dose, or as advised by your doctor.

Precautions and Warnings

• Agranulocytosis can happen at any time, even after previous safe use; blood counts may be checked with longer treatment.
• Use with caution in kidney or liver disease, low blood pressure, dehydration or heart problems.
• Older people may need lower doses.
• Do not use for minor pain where a milder painkiller would work.

Overdose

Overdose may cause nausea, vomiting, stomach pain, drowsiness, low blood pressure, fast heartbeat, kidney problems and seizures. Seek emergency medical help at once.

Therapeutic Class

Non-opioid analgesic and antipyretic (pyrazolone derivative).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Injections: as directed on the pack.