13. Paracetamol
• Acetaminophen, Tylenol, Panadol etc.
• 500mg UK, vs 375mg U.S.A
• 60-90% bioavailability orally and onset 35-40 minutes
• 8 minutes IV
• Metabolised in liver; excreted by kidneys, relatively safe in pregnancy
• Under 50kg – 500mg, QDS
• Over 50kg – 1gm, QDS
• Still kills a lot of people after deliberate or accidental overdose!
18. NSAIDs
• Balance risk vs benefit
• Controversy of COX specific inhibitors and cardiac risk
• Now seems to be an issue with all NSAIDs
• Use the lowest dose possible for least amount of time.
• Wean off first.
• Review after 2 weeks, especially in at risk groups.
• Stop immediately if any side-effects at all.
• Prefer Ibuprofen, 400mg TDS – protect stomach.
19. Opiates and Opioids - Morphine
• Morphine oral bioavailability is about 23%
• Peak levels after 45 minutes in liquid form
• Hepatic metabolism to an active metabolite
• 5-10mg (10mg in 5ml) oromorph, 4 hourly prn.
• S/E constipation, nausea, itching, urinary retention, sedation
• BUT, no organ toxicity, unlike NSAIDs
20. Opiates and Opioids - Codeine
• Codeine has more predictable oral bioavailability, 90%
• 15-30 minute onset
• Metabolised to morphine in liver
• Cytochrome P450 enzyme is gene sensitive. Some can and others
can’t metabolise. Variability in effectiveness.
• Used with paracetamol and NSAIDs
• S/E limit usage
• Max 60mg QDS daily
21. Opiates and Opioids - Tramadol
• Not a purely opioid mechanism
• Has 5HT (serotonin) and Noradrenaline actions
• 15-30 minute onset
• Metabolised to morphine in liver
• Cytochrome P450 enzyme is gene sensitive. Some can and others
can’t metabolise. Variability in effectiveness.
• Used with paracetamol and NSAIDs
• S/E limit usage
• Max 100mg QDS daily