What are the main classes of analgesics?
Paracetamol
Paracetamol (acetaminophen) reduces pain and fever primarily through its action in the central nervous system, particularly by selectively inhibiting enzymes and possibly through effects on neurotransmitter systems. However, it has limited effects on inflammation, which is why it’s not classified as an anti-inflammatory drug.
Non-steroidal anti-inflammatory drugs (NSAIDS)
Traditional NSAIDs (Ibuprofen or naproxen) inhibit both COX-1 and COX-2. COX-1 and COX-2 are two forms of the enzyme cyclo-oxygenase, each with distinct roles. COX-1 is a "housekeeping" enzyme found in many tissues and continuously produces prostaglandins that protect the stomach lining, support kidney function, and aid in blood clotting. Inhibiting COX-1, as with traditional NSAIDs, can lead to gastrointestinal side effects like ulcers. COX-2, on the other hand, is usually produced only in response to inflammation or injury, creating prostaglandins that cause pain and swelling. Selectively inhibiting COX-2, as with drugs like celecoxib, targets pain and inflammation while minimizing gastrointestinal risks.
Celecoxib is a selective COX-2 inhibitor, which means it works by specifically targeting the COX-2 enzyme (cyclo-oxygenase-2). Celecoxib’s is effective for chronic inflammatory conditions, such as osteoarthritis and rheumatoid arthritis, where ongoing inflammation needs to be managed. It’s also used to relieve acute pain in certain cases, such as menstrual pain and post-surgical pain, making it a versatile option in pain management. The selective inhibition of COX-2 allows celecoxib to provide effective relief with fewer gastrointestinal side effects than many traditional NSAIDs, although it still requires careful use due to potential cardiovascular risks associated with COX-2 inhibitors.
Opioids
Opioids work by binding to specific receptors in the brain, spinal cord, and other areas of the body, primarily the mu-opioid receptors. This binding blocks pain signals from being transmitted to the brain and alters the perception of pain, leading to pain relief. Opioids also stimulate the brain's reward system, which can cause feelings of euphoria. In addition to pain relief, opioids can cause side effects like sedation, respiratory depression, and constipation. Their effectiveness and side effects vary depending on factors like metabolism and dosage.
Oxycodone is often preferred to codeine due to its higher potency, more predictable efficacy, and consistency in pain management. While codeine may still be used for mild pain, oxycodone is better suited for managing moderate to severe pain and is generally more reliable in providing adequate pain relief, especially in dental and surgical contexts. However, due to its potency, oxycodone is also associated with a higher risk of side effects and misuse, which is why it is typically prescribed with caution.
Relief of Pain in Adults
What is the typical dosage for mild to moderate dental pain in adults?
One of:
Ibuprofen 400mg orally 6 - 8 hourly for the shortest duration possible and for no more than five days without review |
Celecoxib 100mg orally twice daily for the shortest duration possible, and no more than five days without review. |
PLUS
Paracetamol 1000mg orally 6 hourly up to 4g a day for the shortest period possible |
Once the tissue heals, stop celecoxib and use paracetamol as a single drug.
Are there patients whom NSAIDS should not be given?
Yes , patients who cannot receive NSAIDs include those with cardiovascular problems, kidney problems (GMR < 30L/ min), gastrointestinal toxicity, and pregnant women who are over 32 weeks.
What can be used for relief of mild to moderate pain if NSAIDs are contraindicated?
In patients in which NSAIDs are contraindicated, proceed to give paracetamol alone.
Paracetamol 1000mg orally 6 hourly up to 4g a day for the shortest period possible |
Moderate to Severe Dental Pain
What is the typical dosage for moderate to severe dental pain?
One of:
Ibuprofen 400mg orally 6 hourly up to 4g a day for no more than five days without review |
Celecoxib 100mg orally twice daily for the shortest duration possible, and no more than five days without review. |
PLUS
Paracetamol 1000mg orally 6 hourly up to 4g a day (children 10mg/kg up to 4g a day) for the shortest period possible |
PLUS
Oxycodone immediate - release 5mg orally, every 4 or 6 hours as necessary, for the shortest duration possible and no more than 3 days. Use a lower dose in elderly or frail patients because they are particularly vulnerable to adverse effects. Prescribe small doses to avoid inappropriate use in the community. |
Once the tissue heals, stop celecoxib and use paracetamol as a single drug.
Relief of Pain in Children
For acute pain in children 3 months or older, use ibuprofen or paracetamol; ibuprofen and paracetamol can be combined for enhanced pain management. Give doses regularly rather than as a required, to achieve continuous pain relief.
Either/ or/ and
Ibuprofen ( 5 or 10mg/kg up to 400 mg orally), 3 times daily at 6 - 8 hourly intervals. Continue treatment for the shortest duration possible and no more than 3 days without review |
Paracetamol 15mg/kg up to 1000mg orally, 4 times daily, at 4 to 6 hour intervals). Continue treatment for the shortest duration possible. |
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