Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1   Pharmacodynamic properties
Pharmacotherapeutic group: propionic acid derivative
ATC Code: M01A E01
Ibuprofen is an NSAID that has demonstrated its efficacy in the common animal experimental inflammation models by inhibition of prostaglandin synthesis. In humans, ibuprofen reduces inflammatory pain, swellings and fever. Furthermore, ibuprofen reversibly inhibits platelet aggregation.

The clinical efficacy of ibuprofen has been demonstrated in pain associated with headache, toothache and dysmenorrhoea and fever; furthermore in patients with pain and fever associated with cold and flu and in pain models such as sore throat, muscular pain or soft tissue injury and backache.

A study in dental pain has shown that patients experienced statistically significant pain relief in 15 minutes after the administration of 2 x Nurofen Quick 256 mg Tablets, compared with placebo. In this study, significantly more patients achieved meaningful pain relief after administration of 2 x Nurofen Quick 256 mg Tablets than after administration of paracetamol tablets (96.3% vs 67.9%). These patients also achieved significantly greater reduction in pain intensity and greater pain relief over 6 hours compared with patients receiving paracetamol. Using measures of distractibility, patients receiving sodium ibuprofen experienced significantly greater benefit than those receiving placebo.

Clinical evidence demonstrates that ibuprofen, in the form of salts such as ibuprofen sodium and ibuprofen lysine, acts significantly faster than standard ibuprofen acid tablets for the relief of mild-moderate pain.

Clinical evidence demonstrates that when 400 mg of ibuprofen is taken the pain-relieving effects can last for up to 8 hours.

Experimental data suggest that ibuprofen may competitively inhibit the effect of low dose aspirin (acetylsalicylic acid) on platelet aggregation when they are dosed concomitantly. Some pharmacodynamics studies show that when single doses of ibuprofen 400 mg was taken within 8 h before or within 30 min after immediate release aspirin (acetylsalicylic acid) dosing (81 mg), a decreased effect of aspirin (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 cardioprotective 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).

Pharmacokinetic Properties

5.2   Pharmacokinetic properties
Ibuprofen is well absorbed from the gastrointestinal tract. Ibuprofen is extensively bound to plasma proteins. Ibuprofen diffuses into the synovial fluid.

Maximum plasma concentrations of ibuprofen are reached 45 minutes after ingestion if taken on an empty stomach. When taken with food, peak plasma concentration of ibuprofen occurs 1 - 2 hours after administration. However, ibuprofen is more rapidly absorbed from the gastrointestinal tract following the administration of Nurofen Quick 256 mg Tablets or Nurofen Quick 512 mg Tablets, with peak plasma concentration occurring approximately 35 minutes after administration when taken on an empty stomach.

Ibuprofen is metabolised in the liver to two major metabolites with primary excretion via the kidneys, either as such or as major conjugates, together with a negligible amount of unchanged ibuprofen. Excretion by the kidney is both rapid and complete.

Elimination half-life is approximately 2 hours.

No significant differences in pharmacokinetic profile are observed in the elderly.

In limited studies, ibuprofen appears in the breast milk in very low concentrations.