Therapy and management of chronic pain is an important aspect of medicine. Chronic pain, regardless of its cause, considerably reduces the life-quality of patients. Most common forms of chronic pain are back pain, joint pain, headaches, etc. Absolutely special issue is management of pain in malignant diseases.
Today's medicine has a variety of means to suppress the pain and to bring the desired relief. There is a large selection of painkillers varying in strength, mechanism of action and side effects. In addition, there are less commonly used non-pharmacological methods of pain therapy.
These drugs are used extensively. They are probably the most commonly used and abused drugs worldwide. It is a diverse mix of many substances that can block the enzyme known as cyclooxygenase. This enzyme is responsible, among other things, for production of defensive compounds that cause the perception of pain. By blocking the enzyme, the pain is temporarily suppressed. The effect is satisfactory in headaches, back pain and joint pain. NSAID group of drugs includes substances such as acetylisalicylic acid, ibuprofen, nimesulid, indomethacin, diclofenac and many more.
These drugs have many undesirable effects. These are usually not serious, but some of them may be even life-threatening. The main side effects include kidney damage, dyspepsia, bleeding into digestive tube and the risk of peptic ulcer. NSAID are generally associated with increased tendency of bleeding.
The substance known as paracetamol is very similar to non-steroidal anti-inflammatory drugs. It is a very effective painkiller, especially in combination with other medications. Paracetamol may be used in oral tablets, powder for water solutions and even in intravenous injections.
This group includes, for example, the compound tramadol. It is widely used and served in form of tablets, drops, suppositories, subcutaneously or intravenously. Very popular are combinations of tramadol with cetaminophen.
These are the strongest drugs commonly used against chronic pain. These include morphine and fentanyl. The drugs can be used in tablets, injections, or special skin patches. Patches are great for home therapy of severe pain; they are stuck on the skin and changed every three days. The opioids are gradually released from the patch, ensuring continuous effect of the active substance.
Opioids have aside effects mainly in the digestive system, impairing its mobility. This manifests with loss of appetite, nausea and sometimes even vomiting. When these symptoms appear, we must either reduce the dose of the given opioid, or support the motility of digestive tube by a prokinetic agent.
Other side effect is general drowsiness; very high doses may cause unconsciousness and suppression of the respiratory center. This effect can be observed in higher doses of strong opioids administered subcutaneously or intravenously.
Auxiliary analgesic drugs
This group includes a number of drugs from different classes that have proven to effectively suppress the pain. Most commonly used are certain antidepressants and antiepileptic drugs. Antiepileptics are effective in therapy of neurogenic pain, which is typical for example for shingles.
The WHO analgesic ladder is used mainly (but not only) in the treatment of cancer pain. The point is that the treatment of pain gradually moves from less powerful substances to those stronger, preferring their combinations.
The aim is to achieve satisfactory pain relief with the lowest dose of analgesics as possible. This should guarantee minimal side effects. When the pain gradually deteriorates, we can increase the dosage and strength of painkillers, thus “climbing up the analgesic ladder”.
The general analgesic ladder looks like this:
- 1st choice: Non-steroidal anti-inflammatory drug (+ auxiliary drugs)
- 2nd choice: Weak opioid + NSAID (+ auxiliary drugs)
- 3rd choice: Strong opioid + NSAID (+ auxiliary drugs)
Right combination of drugs plays a significant role in the resulting effect. NSAID alone are not strong, but a combination with an opioid multiplies their effect. In addition, such combination allows us to use a much lower dose of the opioid and reduce the risk of its side effects.
Evaluation of the effect
Effects of analgesic therapy can not be evaluated objectively. The most important is the patient's feeling and satisfaction. The objectification is possible by the so-called curve of pain. It is simple – we ask the patient to tell us about his perception of pain and describe its intensity on a scale from 0 to 10 (0 is for minimal pain and 10 is for the strongest pain) before- and during the therapy. Resulting chart with curves serves for evaluation of our success (or failure).
Radiotherapy of pain
Bone pain can be sometimes solved by radiotherapy. This is very effective in therapy of bone metastases in the lumbar vertebral column. Bone metastases are typical for certain cancers such as breast cancer, or prostate cancer, causing unpleasant pain. Local radiotherapy is not curative, but it has a relatively good analgesic effect. The symptoms disappear, but the overall prognosis of the disease does not change.
Surgical treatment of pain
Surgical procedures aimed to solve the patient's pain are used in situations when the pharmacotherapy is ineffective and when the radiotherapy is not possible. The surgical intervention should interrupt nerve fibers leading from the area of pain sensation. Very simply said, the procedure should disrupt sensitive nerves, while preserving motoric nerves.