The effect of flurbiprofen (2-(2-fluoro-4-biphenylyl) propionic acid) on platelet function and blood coagulation

Nonsteroidal anti-inflammatory drugs in ophthalmology

Nonsteroidal anti-inflammatory drugs (NSAIDs) are increasingly employed in ophthalmology to reduce miosis and inflammation, manage scleritis, and prevent and treat cystoid macular edema associated with cataract surgery. In addition, they may decrease postoperative pain and photophobia associated with refractive surgery and may reduce the itching associated with allergic conjunctivitis. In recent years, the U.S. Food and Drug Administration has approved new topical NSAIDs, and previously approved NSAIDs have been reformulated. These additions and changes result in different pharmacokinetics and dosing intervals, which may offer therapeutic advantages. For example, therapeutic effects on diabetic retinopathy and age-related macular degeneration may now be achievable. We provide an updated review on NSAIDs and a summary of their current uses in ophthalmology with attention to potential future applications.

Spinal anaesthesia and the use of anticoagulants

This chapter addresses the increasing incidence of spinal haematoma after central neuraxis anaesthesia in patients receiving drugs that affect coagulation. Administration of low-molecular-weight heparins in the perioperative period is highlighted because these drugs remain the 'gold standard' for prophylaxis against deep-vein thrombosis. The performance of spinal anaesthesia in patients already receiving antiplatelet drugs is discussed--as well as special warnings in such a setting. In addition, issues such as those concerning the administration of unfractionated heparin, anti-vitamin K drugs or new antiplatelet and antithrombotic medications are addressed. Finally, specific recommendations regarding each class of drug are defined in order to avoid the occurrence of a rare but catastrophic event such as spinal haematoma.

Effect of nabumetone on hemostasis during arthroscopic knee surgery

The known effects of commonly used nonsteroidal anti-inflammatory drugs (NSAIDs) on hemostatic parameters have led to concern over their use in the perioperative period. Nabumetone, unlike other NSAIDs, has little effect on collagen-induced platelet aggregation. To evaluate the effect of nabumetone 2000 mg daily on other hemostatic parameters (e.g., bleeding time, prothrombin time, and partial thromboplastin time) in the clinical setting, this double-masked study was conducted in patients with osteoarthritis undergoing arthroscopic knee surgery. After a 1-week placebo washout period, 58 patients were randomized to receive nabumetone and 53 were randomized to receive placebo. They were assessed before surgery (after 1 to 2 weeks of treatment) and again after surgery (after an additional 3 weeks of treatment). The study was designed to have 90% power to show equivalence in bleeding time to within 1.5 minutes, a difference assumed to be of no clinical importance. No meaningful differences were observed between the groups in any of the measured hemostatic parameters. Before surgery, the bleeding time increased by only 0.3 minutes with nabumetone and decreased by 0.2 minutes with placebo. The mean (+/- SD) difference between the groups in change from baseline was 0.5 +/- 0.3 minutes. After surgery, the changes were 0.1 minutes and 0.0 minutes, respectively, and the difference between groups was 0.2 +/- 0.3 minutes. These differences were neither statistically nor clinically significant, and maximum individual increases were similar in each group. Furthermore, there were no reports of abnormal bleeding in the operative knees. The results of this study show that nabumetone had little or no effect on hemostasis and suggest that this drug can be used safely in the perioperative period.

Clinical pharmacokinetics of flurbiprofen and its enantiomers

Flurbiprofen is a chiral nonsteroidal anti-inflammatory drug (NSAID) of the 2-arylpropionic acid class. Although it possesses a chiral centre, with the S-(+)-enantiomer possessing most of the beneficial anti-inflammatory activity, both enantiomers may possess analgesic activity and all flurbiprofen preparations to date are marketed as the racemate. Flurbiprofen exhibits stereoselectivity in its pharmacokinetics. Stereoselectivity is exhibited at the level of protein binding and metabolite formation. Hence, the data generated using nonstereoselective assays may not be used to explain the pharmacokinetics of individual enantiomers. The absorption of flurbiprofen is rapid and almost complete when given orally. The area under the plasma concentration-time curve of flurbiprofen is proportional to the dose administered to patients. Sustained release dosage forms are available, which may be beneficial due to the short terminal phase elimination half-life of conventional immediate release flurbiprofen (3 to 6 hours). They may also decrease local gastrointestinal adverse effects. Although with these preparations the peak plasma drug concentration is reduced and time taken to achieve peak concentrations is prolonged, the bioavailability is the same as that with regular release counterparts. Flurbiprofen binds extensively to plasma albumin, apparently in a stereoselective manner. Substantial concentrations of the drug are attained in synovial fluid, which is the proposed site of action of NSAIDs. There is negligible R to S inversion after oral administration. Flurbiprofen is eliminated following extensive biotransformation to glucuro-conjugated metabolites. Conjugates are excreted in urine, and approximately 20% of flurbiprofen is eliminated unchanged. The excretion of conjugates may be tied to renal function as accumulation of conjugates occurs in end-stage renal disease, but not in young individuals or elderly patients. Although flurbiprofen is excreted into breast milk, the amount of drug transferred comprises only a small fraction of the maternal exposure. Significant drug interactions have been demonstrated for aspirin (acetylsalicylic acid), coumarins and propranolol. The relationship between concentration and anti-inflammatory and analgesic effect has yet to be elucidated for this drug.

[Comparison of the effects of ketorolac and aspirin on hemostasis in the rabbit]

OBJECTIVE

Comparison of ketorolac with aspirin and placebo for the antithrombotic activity using the Folts' model of experimental arterial thrombosis and the perioperative blood loss.

STUDY DESIGN

Experimental randomized blinded study anaesthetized, tracheotomized and mechanically ventilated. Carotid blood flow variations were detected by a probe directly inserted around the artery and monitored by an electromagnetic flowmeter. A segment of the exposed carotid artery was de-endothelialized by gently squeezing the artery with a needle holder forceps, and an external constrictor was placed around it (stenosis 60%), to induce cyclic flow reductions (CFR). During 20 min, CFR rate was assessed. Animals were then randomized in 3 groups of 9: ketorolac (K) 1 mg.kg-1, aspirin (A) 10 mg.kg-1 or saline (S), injected intravenously (peripheral ear vein). After drug administration, CFR rate was assessed over 20 min, to determine the potential antithrombotic activity of the drug (curative phase). Thereafter, the opposite carotid artery was injured and stenosed and the occurrence of CFR was assessed over 20 min (preventive phase). The amount of blood loss of a xipho-pubic laparotomy with a spleen section was also measured 30 min after drug administration.

RESULTS

In all untreated animals, CFRs developed with a mean rate of 4 cycles/20 min. Aspirin completely abolished CFR during the curative phase in all rabbits, except in one. No effect was observed during this phase with ketorolac or saline. During the preventive phase, a partial inhibition of CFRs was induced by ketorolac and aspirin. Peri-operative bleeding was not increased significantly by ketorolac or aspirin. Postinjection bleeding-time did not differ between the three groups.

CONCLUSIONS

Ketorolac (1mg.kg-1) has not a strong antithrombotic activity. Ketorolac and aspirin do not increase peri-operative blood loss, and therefore do not seem to strongly interfere with haemostasis in the rabbit.

Cyclo-oxygenase inhibitors in ophthalmology

Cyclo-oxygenase inhibitors, which are formulated as ophthalmic eyedrop preparations, have recently become commercially available for use by ophthalmologists in the United States to inhibit intraoperative miosis during cataract surgery and to prevent postoperative inflammation. In addition, they are available worldwide as ocular antiinflammatory drugs and are used in the prevention and treatment of pseudophakic and aphakic cystoid macular edema. Understanding the rationale behind the use of these agents requires an understanding of the pathophysiology of the cyclo-oxygenase inhibitors. In this review recent advances in laboratory and clinical science are emphasized. The role of COIs during and following surgery is examined.

Preoperative nonsteroidal anti-inflammatory medication for the prevention of postoperative dental pain

It is predictable for patients to experience postoperative pain and inflammation. Until recently, therapeutic strategies for the management of these sequelae have been symptomatic rather than preventive. This article reviews prophylactic use of nonsteroidal anti-inflammatory medication for preventing postoperative discomfort, and includes recommendations on patient selection and medication regiment.

Suppression of dental pain by the preoperative administration of flurbiprofen

In a series of three studies involving dental outpatients undergoing removal of impacted third molars, preoperative and postoperative administration of flurbiprofen (Ansaid, Upjohn) led to superior pain relief when compared with acetaminophen alone or in combination with oxycodone. Patient preference and global evaluations clearly favored flurbiprofen. Side effects were mild and generally more common in patients receiving the opiate/mild analgesic combination. In two additional studies, flurbiprofen and etidocaine, a long-acting local anesthetic, also resulted in significantly less postoperative pain than a combination of acetaminophen/oxycodone and lidocaine; 67 percent of patients in the flurbiprofen plus etidocaine group reported no or only slight pain during the entire observation period. The greater analgesic efficacy of flurbiprofen appears to represent a genuine therapeutic advantage, since it is not achieved at the expense of greater side effects.

Clinical pharmacology of flurbiprofen: a novel inhibitor of platelet aggregation

Studies are reviewed of the inhibitory effect of flurbiprofen, given in doses ranging from 50 mg to 200 mg per day for 1 week, on platelet aggregation measured by biological tests (adenosine diphosphate and collagen methods). Flurbiprofen at doses of 50 mg and 100 mg daily had a peak time of action of between 1 and 2 hours, the effects usually disappearing after 24 hours, and 100 mg flurbiprofen caused a similar decrease in platelet aggregation to 1 g aspirin daily. In a clinical study of 72 patients with chronic glomerulonephritis treated with doses of flurbiprofen up to 200 daily there was a significant correlation between the parameters of aggregation measured and treatment, and between proteinuria and adenosine disphosphate aggregation when the flurbiprofen dose did not exceed 100 mg daily.

The effect oa a new anti-inflammatory drug, flurbiprofen, on the respiratory, haemodynamic and metabolic responses to E. coli endotoxin shock in the cat

1 The intravenous administration of E. coli endotoxin (2.0 mg/kg) in cats anaesthetized with sodium pentobarbitone resulted in immediate pulmonary hypertension and reductions in lung compliance and systemic arterial PO2. These effects were abolished, or greatly reduced, by the prior intravenous administration of flurbiprofen in doses (100 and 250 mug/kg and 1.0 mg/kg) which were devoid of cardiovascular or metabolic effects. Flurbiprofen is thus the most active antipyretic-analgesic drug so far examined in this experiment model. 2 Production of lactate, characteristic of the severe, secondary endotoxin shock phase, was delayed only by the highest dose of flubiprofen; hypotension, hypoglycaemia and the reduction in cardiac output which occurs during this phase, were unaffected. 3 These findings are discussed with reference to the treatment of the (shocked lung" syndrome of human septicaemia.