From a medical point of view, pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage and, at the same time, a response of the body that mobilizes various functional systems to protect it from a pathogenic factor (as defined by the International Association for the Study of Pain (IASP)).
In other words, pain is one of the main manifestations of many diseases, very often the only one – the sign that draws a person’s attention to the state of their health.
Getting rid of pain is what most sick people want. But the choice of painkillers is very often emotional and hasty. Potent drugs may be taken without considering age, side effects or unwanted effects, and even without a doctor’s prescription or recommendation.
Specialists who often use analgesics in their practice know that pain relief therapy is not free of risk, so they must warn patients about the complications that may occur during treatment.
A simplified classification of analgesics:
Narcotic (opioid) analgesics:
- Opium alkaloids — morphine, codeine, Omnopon
- Synthetic morphine substitutes: ethylmorphine hydrochloride, Promedol (trimeperidine), fentanyl, sufentanil, methadone, Dipidolor (piritramide), Estocin, pentazocine, tramadol (Tramal), butorphanol (Moradol), buprenorphine
Non-opioid analgesics:
- Salicylates — acetylsalicylic acid, Acelysin (aspirin), sodium salicylate.
- Pyrazolone and indoleacetic acid derivatives: indomethacin (Metindol), Butadion (phenylbutazone), Analgin (metamizole sodium).
- Para-aminophenol derivatives: paracetamol (Panadol, Lekadol).
- Derivatives of pyrrolizine carboxylic acid (ketorolac).
- Alkanoic acid derivatives: ibuprofen, diclofenac sodium (Voltaren, Ortofen), naproxen (Naprosyn).
- Drugs with other chemical structures — mefenamic acid, sodium mefenaminate, piroxicam, meloxicam (Movalis).
- Combination drugs: Reopyrin, Sedalgin, Tempalgin, Baralgin, Citramon, Citropak, Cyclopak, Askonar, Paravit.
Opioid analgesics are prescribed to treat severe pain when non-opioid drugs are ineffective. Cancer patients are the ones who most often need opioids.
Side effects: Cardiovascular system: bradycardia.
Respiratory system: respiratory depression.
Nervous system: sedative or stimulating effect (especially in elderly patients), delirium, hallucinations, increased intracranial pressure with a possible subsequent disorder of cerebral circulation.
Digestive system: nausea, vomiting, constipation, cholestasis in the common bile duct.
Urinary system: impaired outflow of urine, or worsening of this condition in prostate adenoma and urethral stricture.
Other: allergic reactions.
Non-opioid analgesics.
1. Aspirin (acetylsalicylic acid).
Most common side effects: heartburn, vomiting, nausea. Keep in mind the risk of gastrointestinal ulcers and prolonged bleeding time.
2. Analgin (metamizole sodium).
Of note is the frequent occurrence of allergic reactions, agranulocytosis, leukopenia and thrombocytopenia (its use is banned in many developed countries).
3. Paracetamol.
Be aware of its toxic effect on liver function (at high doses). Allergic reactions, anemia and gastrointestinal disorders are also possible. Using infusion forms (Infulgan, Ifimol) helps reduce the frequency of the latter.
4. Ketorolac (Ketanov, Ketorol).
It affects blood clotting, increasing the risk of bleeding, and is also toxic to the kidneys (the maximum duration of use is 5 days). Visual and taste disturbances, insomnia and dizziness are common.
5. Meloxicam (Movalis).
Very often it causes gastrointestinal disorders (bloating, constipation) and anemia.
In general, all non-opioid analgesics (most of them are non-steroidal anti-inflammatory drugs) have side effects related to the suppression of prostaglandin synthesis: changes in the endothelium, reduced renal blood flow, coagulopathies, and others.
This process occurs both at the site of inflammation or injury and in healthy tissues.
Published research has shown significant cardiotoxic effects of non-steroidal anti-inflammatory drugs.
Therefore, starting pain relief therapy, especially if it is planned for several days, requires a careful assessment of the potential risks.
Serhii Lutsyk – head of the anesthesiology and intensive care department
Sumy Regional Clinical Oncology Center.