Source: Health Products Regulatory Authority (ZA) Revision Year: 2023 Publisher: Sandoz SA (Pty) Ltd<sup>1</sup>, Magwa Crescent West, Waterfall City, Jukskei View, Midrand, 2090 1 Company Reg. No.: 1990/001979/07
Pharmacological classification: A 2.8 Analgesic combinations
Paracetamol has analgesic and antipyretic effects. The mechanism of action is probably similar to that of aspirin and dependant on the inhibition of prostaglandin synthesis. This inhibition appears, however to be on a selective basis.
Ibuprofen has analgesic, antipyretic and anti-inflammatory activities. Ibuprofen is a non-steroidal anti-inflammatory medicine that, in the conventional animal-experiment inflammation models, has proven to be effective via prostaglandin synthesis inhibition. In humans, ibuprofen reduces inflammatory-related pain, swelling and fever. Furthermore, ibuprofen reversibly inhibits ADP- and collagen-induced platelet aggregation.
Experimental data suggest that ibuprofen may competitively inhibit the effect of low dose acetylsalicylic acid on platelet aggregation when they are dosed concomitantly. Some pharmacodynamic studies show that when single doses of ibuprofen 400 mg were taken within 8 h before or within 30 min after immediate release acetylsalicylic acid dosing (81 mg), a decreased effect of acetylsalicylic acid on the formation of thromboxane or platelet aggregation occurred. Although there are uncertainties regarding extrapolation of these data to the clinical situation, the possibility that regular, long-term use of ibuprofen may reduce the cardio-protective effect of low-dose acetylsalicylic acid cannot be excluded. No clinically relevant effect is considered to be likely for occasional ibuprofen use (see section 4.5).
Codeine is a centrally acting weak analgesic. Codeine exerts its effect through μ opioid receptors, although codeine has low affinity for these receptors, and its analgesic effect is due to its conversion to morphine. Codeine, particularly in combination with other analgesics such as paracetamol, has been shown to be effective in acute nociceptive pain.
Paracetamol is rapidly absorbed from the upper gastrointestinal tract after oral administration. Paracetamol is metabolised in the liver primarily by conjugation. Paracetamol has a half-life of 1 to 4 hours, time to peak concentration of 0,5 to 2 hours, time to peak effect of 1 to 3 hours and the duration of action of 3 to 4 hours. Paracetamol is renally excreted primarily as metabolites and 3% of a dose may be excreted unchanged.
Rapidly absorbed after oral administration. Onset of action for pain relief is 30 minutes and the time for peak effect for fever is 2 to 4 hours. The half-life of ibuprofen is about 2 hours and the duration of action for fever is 6 to 8 hours or more and is 4 to 6 hours for pain. More than 90 % of an ingested dose is excreted in the urine as metabolites or their conjugates.
Readily absorbed from the gastrointestinal tract. Half-life is 2,5 to 4 hours. Codeine is metabolised in the liver. The cytochrome P450 enzyme 2D6 converts codeine to morphine, one of its metabolites. About 10% of the dose is demethylated to morphine. Onset of action is 30 to 45 minutes. The time to peak effect is 1 to 2 hours. Duration of action is 4 hours. Codeine is eliminated via the kidneys.
Conventional studies using the currently accepted standards for the evaluation of toxicity to reproduction and development are not available.
Not applicable.
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