Codeine and Ibuprofen

Ibuprofen is an NSAID which acts peripherally, inhibiting prostaglandin synthesis and the action of chemical mediators of pain. In humans, ibuprofen reduces inflammatory pain, swellings and fever. Furthermore, ibuprofen reversibly inhibits platelet aggregation. Codeine is a narcotic analgesic acting on central opiate receptors, although its pharmacological effects are thought to be due largely to its biotransformation to morphine.

The combination of a well tolerated peripheral analgesic with a centrally acting analgesic provides optimum pain relief with a lower potential for producing side effects.

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.

The combination of the two drugs is appropriate from a pharmacokinetic viewpoint; the tablet exhibits normal release characteristics for both active substances.

Ibuprofen is rapidly absorbed from the gastrointestinal tract following administration and is rapidly distributed throughout the whole body. It is extensively bound to plasma proteins and diffused into the synovial fluid. The excretion is rapid and complete via the kidneys.

Maximum plasma concentrations are reached 45 minutes after ingestion if taken on an empty stomach. When taken with food, peak levels are observed after one to two hours. These times may vary with different dosage forms.

The half-life of ibuprofen is about two hours.

Codeine phosphate is well absorbed after oral administration, producing peak plasma concentrations in about one hour. The plasma half-life is approximately three hours, excretion being mainly in the urine.

Not applicable.