Pharmacological Therapies for Pain Management

Comprehensive vocabulary flashcards covering common pharmacological agents for pain management, including mechanisms of action, side effects, and specific drug risks.

Paracetamol

An analgesic and antipyretic that inhibits prostaglandin synthesis in the CNS and acts on the hypothalamus to reduce body temperature; it lacks anti-inflammatory properties.

NSAIDs

Drugs that reduce prostaglandin production via the inhibition of COX enzymes, providing analgesic, antipyretic, and anti-inflammatory effects.

Highest Thrombotic Risk NSAIDs

COX-2 inhibitors, Diclofenac ($150\,mg$ daily), and high dose Ibuprofen ($2.4\,g$ daily).

NSAID Renal Risk Mechanism

Inhibiting prostaglandins prevents vasodilation in the afferent arterioles, which can lead to acute renal failure, sodium retention, and increased BP.

5-lipoxygenase pathway

A pathway that metabolizes arachidonic acid when COX is inhibited, leading to increased production of leukotrienes ($LTC_4$, $LTD_4$, and $LTE_4$) which cause bronchoconstriction.

Nefopam

A centrally-acting analgesic that inhibits the reuptake of dopamine, noradrenaline, and serotonin, and inhibits pain signal transmission.

Mu receptors

The type of opioid receptors most closely associated with euphoria and pain relief.

Opioid Tolerance

A process where the body downregulates the number of opioid receptors and they become less sensitive to agonist activity, requiring higher doses for the same effect.

Opioid Dependence

A state where patients experience withdrawal symptoms if the opioid is not taken, potentially leading to drug-seeking behavior.

The Opioid Triad

Key symptoms of an overdose: respiratory depression, heavy sedation or lack of consciousness, and miosis (constricted pupils).

Codeine

A pro-drug of morphine with $\frac{1}{10}$ the potency, requiring CYP2D6 activity for metabolism into an active analgesic.

Tramadol

A weak opioid that achieves analgesic effects through opioid receptor agonism and serotonin and noradrenaline reuptake inhibition (SNRI); it can lower the seizure threshold.

Tapentadol

An atypical potent analgesic with mu-agonistic opioid and noradrenaline reuptake inhibition properties; it is less likely to cause GI side effects than strong opioids.

Buprenorphine

A partial agonist of mu-receptors with high affinity and slow dissociation, resulting in a ceiling effect for analgesia and respiratory depression.

Naloxone

An opioid antagonist used to reverse respiratory depression in the event of an overdose.

Capsaicin Cream

A topical treatment derived from chilli peppers that initially causes a burning sensation but desensitizes pain receptors with continued exposure.

Lidocaine Patches

A local anaesthetic that blocks voltage-gated sodium channels in nerve cells, applied for up to 12 hours to treat postherpetic neuralgia.