Diflunisal: a review of its pharmacological properties and therapeutic use in pain and musculoskeletal strains and sprains and pain in osteoarthritis

Repurposing of FDA-approved drugs as dual-acting MAO-B and AChE inhibitors against Alzheimer's disease: An in silico and in vitro study

An in silico consensus molecular docking approach and in vitro evaluations were adopted in the present study to explore a dataset of FDA-approved drugs as novel multitarget MAO-B/AChE agents in the treatment of Alzheimer's disease (AD). GOLD 5.3 and Glide were employed in the virtual assessments and consensus superimpositions of the obtained poses were applied to increase the reliability of the docking protocols. Furthermore, the top ranked molecules were subjected to binding free energy calculations using MM/GBSA, Induced fit docking (IFD) simulations, and a literature review. Consequently, the top four multitarget drugs were examined for their in vitro MAO-B and AChE inhibition effects. The consensus molecular docking identified Dolutegravir, Rebamipide, Loracarbef and Diflunisal as potential multitarget drugs. The biological data demonstrated that most of the docking scores were in good correlation with the in vitro experiments, however the theoretical simulations in the active site of MAO-B identified two false-positives - Rebamipide and Diflunisal. Dolutegravir and Loracarbef were accessed as active MAO-B inhibitors, while Dolutegravir, Rebamapide and Diflunisal as potential AChE inhibitors. The antiretroviral agent Dolutegravir exhibited the most potent multitarget activity - 41% inhibition of MAO-B (1 μM) and 68% inhibition of AChE (10 μM). Visualizations of the intermolecular interactions of Dolutegravir in the active sites of MAO-B and AChE revealed the formation of several stable hydrogen bonds. Overall, Dolutegravir was identified as a potential anti-AD drug, however further in vivo evaluations should be considered.

Iron(III) Complexes with Non-Steroidal Anti-Inflammatory Drugs: Structure, Antioxidant and Anticholinergic Activity, and Interaction with Biomolecules

One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel iron(III) complexes with the non-steroidal anti-inflammatory drugs diflunisal and diclofenac in the presence or absence of the nitrogen donors 1,10-phenanthroline or pyridine were isolated and characterized by diverse techniques. The complexes were evaluated for their ability to scavenge in vitro free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, revealing their selective potency towards hydroxyl radicals. The in vitro inhibitory activity of the complexes towards the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated, and their potential to achieve neuroprotection appeared promising. The interaction of the complexes with calf-thymus DNA was examined in vitro, revealing their ability to intercalate in-between DNA nucleobases. The affinity of the complexes for serum albumins was evaluated in vitro and revealed their tight and reversible binding.

Highly congested spiro-compounds via photoredox-mediated dearomative annulation cascade

Photo-mediated radical dearomatization involving 5-exo-trig cyclizations has proven to be an important route to accessing spirocyclic compounds, whereas 6-exo-trig spirocyclization has been much less explored. In this work, a dearomative annulation cascade is realized through photoredox-mediated C-O bond activation of aromatic carboxylic acids to produce two kinds of spirocyclic frameworks. Mechanistically, the acyl radical is formed through oxidation of triphenylphosphine and subsequent C-O bond cleavage, followed by a 6-exo-trig cyclization/SET/protonation sequence to generate the spiro-chromanone products in an intramolecular manner. Furthermore, the protocol was extended to more challenging intermolecular tandem sequences consisting of C-O bond cleavage, radical addition to an alkene substrate, and 5-exo-trig cyclization to yield complex spirocyclic lactams.

Discovery of MurA Inhibitors as Novel Antimicrobials through an Integrated Computational and Experimental Approach

The bacterial cell wall is essential for protecting bacteria from the surrounding environment and maintaining the integrity of bacteria cells. The MurA enzyme, which is an essential enzyme involved in bacterial cell wall synthesis, could be a good drug target for antibiotics. Although fosfomycin is used clinically as a MurA inhibitor, resistance to this antibiotic is a concern. Here we used molecular docking-based virtual screening approaches to identify potential MurA inhibitors from 1.412 million compounds from three databases. Thirty-three top compounds from virtual screening were experimentally tested in Listeria innocua (Gram-positive bacterium) and Escherichia coli (Gram-negative bacterium). Compound 2-Amino-5-bromobenzimidazole (S17) showed growth inhibition effect in both L. innocua and E. coli, with the same Minimum Inhibitory Concentration (MIC) value of 0.5 mg/mL. Compound 2-[4-(dimethylamino)benzylidene]-n-nitrohydrazinecarboximidamide (C1) had growth inhibition effect only in L. innocua, with a MIC value of 0.5 mg/mL. Two FDA-approved drugs, albendazole (S4) and diflunisal (S8), had a growth inhibition effect only in E. coli, with a MIC value of 0.0625 mg/mL. The identified MurA inhibitors could be potential novel antibiotics. Furthermore, they could be potential fosfomycin substitutes for the fosfomycin-resistant strains.

Advances in deep eutectic solvents and water: applications in metal- and biocatalyzed processes, in the synthesis of APIs, and other biologically active compounds

This review highlights recent advances in metal- and biocatalyzed transformations, in the synthesis of APIs and other biologically active compounds, when employing deep eutectic solvents and water as environmentally responsible solvents.

Ligand-Free Bioinspired Suzuki-Miyaura Coupling Reactions using Aryltrifluoroborates as Effective Partners in Deep Eutectic Solvents

Pd-catalyzed Suzuki-Miyaura cross-coupling between (hetero)aryl halides (Cl, Br, I) and versatile, moisture-stable mono- and bifunctional potassium aryltrifluoroborates proceeded efficiently and chemoselectively in air and under generally mild conditions; a catalyst loading as low as 1 mol % combined with Na₂ CO₃ as a base in choline chloride/glycerol (1:2) deep eutectic solvent (DES) was used as a sustainable and environmentally responsible medium. The catalyst, base, and DES were easily and successfully recycled up to six times with an E-factor as low as 8.74. Valuable biaryls and terphenyl derivatives were furnished in yields of up to 98 %; over 50 reactions were compared and discussed. The methodology was applied for the synthesis of the nonsteroidal anti-inflammatory drugs Felbinac and Diflunisal.

Synthesis and preliminary anti-inflammatory and anti-bacterial evaluation of some diflunisal aza-analogs

Our aim was to identify new multi-target compounds endowed with both anti-inflammatory and anti-bacterial activities for treatment of human infections. Diflunisal, a nonsteroidal anti-inflammatory agent, has recently been repurposed for its anti-virulence properties against methicillin-resistant Staphylococcus aureus. Effective synthesis of some aza-analogs of the anti-inflammatory drug diflunisal was carried out following the route involving key oxazole intermediates to obtain o- and m-hydroxypyridinecarboxylic acid derivatives. The newly synthesized diflunisal aza-analogs did not exhibit cytotoxic activity up to 80 μM and some of them exhibited anti-inflammatory activities, decreasing the levels of pro-inflammatory cytokines and prostaglandins induced by bacterial lipopolysaccharide in human primary macrophages. Ten of the diflunisal aza-analogs were found to have interesting antibacterial activity, sensitizing S. aureus, Streptococcus pyogenes, Enterococcus faecium, and Pseudomonas aeruginosa to the antibacterial effects of beta-lactam antibiotics and protein synthesis inhibitors.

α,β-Poly(N-Hydroxyethyl)-DL-Aspartamide Hydrogels as Drug Delivery Devices

α,β-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) was exposed to gamma radiation to obtain micromatrices able to swell in an aqueous medium. Crosslinked PHEA was loaded with an anti-inflammatory drug, 4-biphenylacetic acid (BPAA) and the drug dispersion in the network was investigated by X-ray analysis. The BPAA loaded PHEA microparticles were also characterized by dimensional analysis, which showed the presence of quasispherical shapes. The drug release from PHEA hydrogel was studied in vitro in a pH 1.1 (simulated gastric juice) and in a pH 7.4 buffer solution, respectively. The experimental data indicate that an anomalous delivery occurs, but Fickian diffusion through swollen PHEA hydrogel seems to be the predominant release mechanism. The interactions between PHEA microparticles and dimyristoil-phosphatidylcholine (DMPC) liposomes, chosen as biomembrane model, were studied by a differential scanning calorimetry (DSC) technique. The calorimetric results show that the cross-linked PHEA network does not interact with the DMPC liposomes.

Central mediators involved in the febrile response: effects of antipyretic drugs

Fever is a complex signal of inflammatory and infectious diseases. It is generally initiated when peripherally produced endogenous pyrogens reach areas that surround the hypothalamus. These peripheral endogenous pyrogens are cytokines that are produced by leukocytes and other cells, the most known of which are interleukin-1β, tumor necrosis factor-α, and interleukin-6. Because of the capacity of these molecules to induce their own synthesis and the synthesis of other cytokines, they can also be synthesized in the central nervous system. However, these pyrogens are not the final mediators of the febrile response. These cytokines can induce the synthesis of cyclooxygenase-2, which produces prostaglandins. These prostanoids alter hypothalamic temperature control, leading to an increase in heat production, the conservation of heat, and ultimately fever. The effect of antipyretics is based on blocking prostaglandin synthesis. In this review, we discuss recent data on the importance of prostaglandins in the febrile response, and we show that some endogenous mediators can still induce the febrile response even when known antipyretics reduce the levels of prostaglandins in the central nervous system. These studies suggest that centrally produced mediators other than prostaglandins participate in the genesis of fever. Among the most studied central mediators of fever are corticotropin-releasing factor, endothelins, chemokines, endogenous opioids, and substance P, which are discussed herein. Additionally, recent evidence suggests that these different pathways of fever induction may be activated during different pathological conditions.

Central mediators involved in the febrile response: effects of antipyretic drugs

Fever is a complex signal of inflammatory and infectious diseases. It is generally initiated when peripherally produced endogenous pyrogens reach areas that surround the hypothalamus. These peripheral endogenous pyrogens are cytokines that are produced by leukocytes and other cells, the most known of which are interleukin-1β, tumor necrosis factor-α, and interleukin-6. Because of the capacity of these molecules to induce their own synthesis and the synthesis of other cytokines, they can also be synthesized in the central nervous system. However, these pyrogens are not the final mediators of the febrile response. These cytokines can induce the synthesis of cyclooxygenase-2, which produces prostaglandins. These prostanoids alter hypothalamic temperature control, leading to an increase in heat production, the conservation of heat, and ultimately fever. The effect of antipyretics is based on blocking prostaglandin synthesis. In this review, we discuss recent data on the importance of prostaglandins in the febrile response, and we show that some endogenous mediators can still induce the febrile response even when known antipyretics reduce the levels of prostaglandins in the central nervous system. These studies suggest that centrally produced mediators other than prostaglandins participate in the genesis of fever. Among the most studied central mediators of fever are corticotropin-releasing factor, endothelins, chemokines, endogenous opioids, and substance P, which are discussed herein. Additionally, recent evidence suggests that these different pathways of fever induction may be activated during different pathological conditions.

Solid dispersions of diflunisal-PVP: polymorphic and amorphous states of the drug

Coprecipitates of diflunisal and polyvinylpyrrolidone (PVP K15, K30, and K90) and physical mixtures were studied using x-ray diffraction analysis, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and hot-stage microscopy. X-ray diffraction results revealed an almost amorphous state, even in coprecipitates with a high content of drug, next to 70%, which was independent of the polymer molecular weight. The IR spectra of 70:30 drug-PVP solid dispersions suggest the formation of diflunisal-PVP hydrogen bonds. For 70:30 drug-polymer ratio, the physical mixture showed linear dissolution kinetics of free crystals, but the corresponding coprecipitates exhibit two different dissolution processes. When the 25:75 drug-polymer dispersion is analyzed by hot-stage microscopy, only solid plates of PVP are observed; the absence of drug particles may be due to a molecular dispersion of the drug into the polymer. Moreover, polymorphic changes of diflunisal were detected in the solid dispersions in comparison with the corresponding physical mixtures, which are always formed by polymorph II. At high concentrations of drug (75:25 and 80:20), x-ray diffraction patterns of solid dispersions showed the partial recrystallization of the drug, displaying the main diffraction peaks of polymorph I when ethanol was used as coprecipitation solvent, whereas diflunisal form IV was obtained in chloroform.

A comparison of two nonsteroidal antiinflammatory drugs (diflunisal versus dipyrone) in the treatment of moderate to severe cancer pain: a randomized crossover study

The efficacy of diflunisal in cancer pain was evaluated and compared with dipyrone. Diflunisal was given at the dosage of 500 mg perorally twice a day, and dipyrone was given at the dosage of 500 mg perorally three times a day. Duration of each treatment was 7 days; after a 12-hour wash-out period, patients were given the other drug for another 7 days. A total of 50 patients were enrolled in the study. Pain intensity was assessed by 10-point visual analog scale (VAS). Patients who had a VAS score higher than 5 were included. A total of 47 patients were evaluable. Initial VAS score was a mean of 8.57+/-1.33. Diflunisal reduced the pain score by a mean of 4.65+/-3.10, whereas dipyrone reduced the pain score by a mean of 3.25 < or = 2.85 (p < 0.001). Patients were also analyzed in three subgroups according to the presence of nonmetastatic, metastatic, and bone metastatic diseases. In each of these subgroups, diflunisal reduced the pain score more than dipyrone; however, the difference was statistically significant only in patients who had bone metastasis. Adverse reactions were rare and acceptable with both drugs. Diflusinal is superior to dipyrone at this dosage and schedule in the treatment of moderate to severe cancer pain.

A hydrogel based on a polyaspartamide: characterization and evaluation of in-vivo biocompatibility and drug release in the rat

This paper deals with the characterization of a new microparticulate hydrogel obtained by gamma irradiation of alpha, beta-poly[N-(2-hydroxyethyl)-DL-aspartamide] (PHEA). When enzymatic digestion of PHEA hydrogel was evaluated using various concentrations of pepsin and alpha-chymotrypsin no degradation occurred within 24 h. In-vivo studies showed that this new material is biocompatible after oral administration to rats. PHEA hydrogel was also studied as a system for delivery of diflunisal, an anti-inflammatory drug. In-vitro release studies in simulated gastrointestinal juice (pH 1 or 6.8) showed that most of the drug was released at pH 6.8. In-vivo studies indicated that diflunisal-loaded PHEA microparticles significantly improved the gastric tolerance and oral bioavailability of the drug in comparison with free diflunisal. These results suggest the potential application of PHEA hydrogel as a new delivery system for the oral administration of anti-inflammatory drugs.

Pharmacokinetics of diflunisal in patients

There are few pharmacokinetic data available on the disposition of diflunisal in patients; this study, therefore, looked at the oral absorption, distribution and elimination of this drug. Ten pharmacokinetic profiles obtained from 8 patients showed a maximum plasma diflunisal concentration of 62.0 +/- 26.5 mg/L after 2.76 +/- 1.87 hours, and an area under the plasma concentration-time curve (AUC) of 678.3 +/- 362.3 mg/L.h. Significant intra- and intersubject variability was observed in this group of patients. Analysis of biliary secretion of diflunisal in 4 patients suggested a biliary elimination and subsequent enterohepatic circulation ranging between 2.4 and 15.1%. The AUC for diflunisal in synovial fluid collected from 66 patients was about 70% of that for plasma. In none of 28 patients studied could any trace of diflunisal be observed in cerebrospinal fluid, even though the sensitivity of the assay allowed detection of concentrations as low as 0.01 mg/L.

Clinical pharmacology and use of nonsteroidal anti-inflammatory drugs

This review informs clinicians about current clinical usage and pharmacokinetics of newer NSAIDs and aspirin. To understand the effects of these drugs, a review of prostaglandin synthesis and actions is provided.

Comparative analgesic and anti-inflammatory properties of sodium salicylate and acetylsalicylic acid (aspirin) in rheumatoid arthritis

1. Enteric coated sodium salicylate 4.8 g daily was compared with the same dose of enteric coated aspirin in 18 patients with rheumatoid arthritis. 2. After an initial washout period lasting 3 days, patients were randomly allocated to treatment with sodium salicylate or aspirin. After 2 weeks the two treatments were crossed over. 3. Pain relief, reduction in articular index of joint tenderness, increase in grip strength, decrease in digital joint circumference and patients' assessment showed significant improvement with both treatments compared with the washout period. No significant differences were found between the two therapies. 4. No correlation was found in the degree of improvement in any of the clinical outcomes and the salicylate concentrations at steady state.

Mechanisms of nonsteroidal anti-inflammatory drug-induced gastric damage

The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on the gastric mucosa are well documented. The complex mechanisms of gastric damage, however, are not fully understood. This review examines current knowledge about the normal function of the gastric mucosal barrier; the role of prostaglandins in cytoprotection and repair; the mechanisms by which aspirin and other weak organic acids are absorbed by the stomach; and the subsequent cascade of events--including ion trapping and back diffusion of hydrogen ions--that leads to gastric erosion and bleeding. A hypothesis describing NSAIDs' dual insult on the stomach is advanced.

High-performance liquid chromatographic method for the simultaneous quantitation of diflunisal and its glucuronide and sulfate conjugates in human urine

A direct high-performance liquid chromatographic (HPLC) assay was developed to simultaneously quantitate diflunisal and its three known metabolites (i.e., the phenolic and acyl glucuronides and the sulfate conjugate) in human urine. Chromatographically pure standards of the diflunisal conjugates were isolated from urine of volunteers following ingestion of multiple doses of diflunisal (500 mg twice daily). Diflunisal, its three conjugates, and an internal standard (naproxen) were separated on a reversed-phase column using gradient elution. The column eluate was monitored fluorometrically (excitation: 258 nm; emission: 428 nm). Urine samples were diluted with phosphate buffer (pH 5.75) and injected onto the column. The limit of detection was approximately 1 microgram/mL for each conjugate and 0.1 microgram/mL for diflunisal. Due to the presence in most urine samples of significant concentrations of rearrangement products of the biosynthetic 1-O-acyl glucuronide of diflunisal, the acyl glucuronide could not be reliably quantitated by direct injection of diluted urine samples. Instead, diflunisal acyl glucuronide was quantitated indirectly following alkaline hydrolysis of the urine samples. The method has been successfully used to investigate the dose-dependent glucuronidation and sulfation of diflunisal in humans.

Effect of dose on the glucuronidation and sulphation kinetics of diflunisal in man: single dose studies

1. The effect of dose (100 mg, 250 mg, 500 mg, 750 mg and 1000 mg) on the glucuronidation and sulphation of diflunisal was studied in six healthy volunteers. 2. Total urinary recovery ranged from 78.9 +/- 11.9% to 91.5 +/- 18.7% of the administered dose. Urinary recovery (normalized for total urinary recovery) of diflunisal sulphate (DS) significantly increased with dose from 9.3 +/- 3.7% to 18.1 +/- 4.8%. 3. Normalized urinary recovery for diflunisal phenolic glucuronide (DPG) was unaffected by dose (range: 30.6 +/- 3.8% to 40.6 +/- 6.6%). Normalized urinary recovery for the acyl glucuronide (DAG) significantly decreased from 52.3 +/- 4.6% to 40.2 +/- 3.4% as the dose increased. 4. Total plasma clearance of diflunisal significantly decreased from 14.4 +/- 1.4 ml min-1 to 8.7 +/- 1.4 ml min-1 as the dose increased from 100 mg to 750 mg. A further increase in dose to 1000 mg resulted in an unexplained increase in total plasma clearance to 10.3 +/- 1.8 ml min-1. 5. Dose-dependent plasma clearance of diflunisal was caused mainly by saturation of the formation of DAG, whereas the formation of DS and DPG were relatively unaffected by dose.

A diflunisal related fatality: a case report

A case is reported where the death of an individual resulted from the ingestion of diflunisal. Diflunisal was identified by a combination of liquid chromatography, UV spectrophotometry and colorimetry. Diflunisal was quantified in blood (260 mg/l), bile (71 mg/l), kidney (350 mg/kg), liver (400 mg/kg), stomach contents (34 mg) and urine (78 mg/l). No previous literature references discussing diflunisal related fatalities were available.

Classical absorption theory and the development of gastric mucosal damage associated with the non-steroidal anti-inflammatory drugs

Evidence has accumulated during the last decade to support the view that the pharmacokinetic behaviour of non-steroidal anti-inflammatory drugs (NSAIDs) contributes not only decisively to their therapeutic effects but also to the type and incidence of their side effects. It has been shown that NSAIDs reach particularly high concentrations in those compartments in which they cause effects and side effects. Specifically, the data reviewed herein indicate that the accumulation of NSAID within gastric mucosal cells a priori is a principal factor associated with the intervention of intracellular biochemical events and resultant gastric mucosal damage. To a large extent this behaviour is according to the precepts of classical absorption theory; in this respect the limitations of such theory are examined. Our survey further indicates that the failure of certain NSAIDs to significantly reduce gastric mucosal levels of prostaglandins (PG) in vivo may reflect pharmacokinetic differences between NSAIDs rather than tissue-specific differences in their potency as inhibitors of cyclo-oxygenase.

A comparison of diflunisal and phenylbutazone in the treatment of ankylosing spondylitis

A 12-week double-blind randomized drug trial followed by an open extension period of 36 weeks was carried out in 38 male patients with ankylosing spondylitis (AS) to compare the efficacy and safety of diflunisal (500 mg twice daily) and phenylbutazone (200 mg twice daily). Both drugs proved to be effective in improving the severity of symptoms associated with AS, and this improvement was maintained throughout the open extension period. Initially diflunisal had a more pronounced and rapid analgesic action, whereas phenylbutazone was more effective in increasing axial mobility. During the study 9 patients dropped out: 3 in each treatment group due to side effects and 1 in each group due to lack of efficacy; another patient was lost to follow-up. The two drugs were similarly safe as judged by the occurrence of adverse clinical effects, mainly gastrointestinal. This study again demonstrates the value of phenylbutazone in AS but, taking into account the possible haematological side effects, the use of other NSAIDs is stressed. Diflunisal is an alternative capable of improving the painful stiffness associated with AS.

Cutaneous reactions to nonsteroidal anti-inflammatory drugs. A review

The nonsteroidal anti-inflammatory drugs are one of the most commonly prescribed classes of drugs used in medical practice. This review discusses the diverse cutaneous reactions associated with nonsteroidal anti-inflammatory drugs. Adverse cutaneous reactions occur most frequently with benoxaprofen, piroxicam, sulindac, meclofenamate sodium, zomepirac sodium, and phenylbutazone. The most serious adverse cutaneous reactions, Stevens-Johnson syndrome and toxic epidermal necrolysis, appear to be most often associated with sulindac and phenylbutazone. Tolmetin and zomepirac sodium, two structurally similar pyrrole derivatives, have been associated with a disproportionate number of cases of anaphylactoid reactions. Among the currently marketed nonsteroidal anti-inflammatory drugs, piroxicam appears to have the highest rate of phototoxic reactions. This phototoxic eruption is most often vesiculobullous.

Systemic availability of oral slow-release morphine in man

In a within-patient crossover study on twelve patients we investigated plasma morphine concentrations for 48 hours after administration of intravenous morphine sulphate followed 24 hours later by oral MST Continus [MST]. Patients received either 10 mg i.v. morphine followed by 10 mg MST or 20 mg i.v. morphine followed by 2 X 10 mg MST tablets. Systemic clearance of morphine was low, being about 3 ml/min/kg after both intravenous and oral administration. The ratio of the areas under the concentration-time curve for MST relative to that for i.v. morphine was about 1:1 for 20 mg doses, but was significantly greater than 1:1 for 10 mg doses. The results suggest high oral systemic availability for morphine and low hepatic morphine metabolism.

Piroxicam. A reappraisal of its pharmacology and therapeutic efficacy

Piroxicam is a chemically different non-steroidal anti-inflammatory drug with a long half-life which enables it to be administered once daily. This member of the oxicam series of compounds is now well established in the treatment of rheumatoid arthritis and osteoarthritis and has been shown to be a suitable alternative to aspirin, indomethacin, naproxen, ibuprofen, ketoprofen, sulindac, phenylbutazone and diclofenac in the treatment of rheumatic diseases. Open trials in many thousands of patients in hospital clinics and in general practice have demonstrated its analgesic and anti-inflammatory efficacy in a wide cross-section of patients with rheumatic diseases, when administered once daily either at night or in the morning, and recent studies have demonstrated its usefulness in musculoskeletal disorders, dysmenorrhoea and postoperative pain. Such studies have also demonstrated the generally good tolerability of piroxicam 20mg daily. As with other non-steroidal anti-inflammatory drugs, gastrointestinal complaints are the most frequently reported side effects. The frequency and severity of these effects are dose related. Thus, piroxicam is now well established in the treatment of rheumatic diseases and offers an alternative to other analgesics in various pain states.

Temporary hearing loss induced by combinations of intense sounds and nonsteroidal anti-inflammatory drugs

Intense sounds were delivered to 11 subjects with normal hearing both before and during administration of standard doses of four nonsteroidal anti-inflammatory drugs. After four days of aspirin treatment (3.9 g daily), the subjects' resting hearing levels raised by about 10 dB. Administration of intense sounds that had previously been shown to produce about 12 dB of temporary hearing loss added increments of 10 to 15 dB to the aspirin-induced hearing loss. That is, the total temporary hearing loss produced by aspirin plus exposure to intense sound was about 10 to 15 dB greater than that produced by exposure to the intense sound alone. A similar effect was observed for sodium salicylate. After similar administrations of sulindac (400 mg per day) and diflunisal (750 mg per day), there was no corresponding increase in the sound-induced hearing loss. Under certain reasonable assumptions about underlying mechanisms, these findings suggest that persons taking moderate doses of aspirin or sodium salicylate may be at increased risk of noise-induced hearing loss.

Non-steroidal anti-inflammatory drugs. Current status and rational therapeutic use

Aspirin (acetylsalicylic acid), the first of the NSAIDs (introduced in 1899), was initially never referred to as an anti-inflammatory agent. It was the advent of cortisone in 1949 that demonstrated dramatically that corticosteroids had anti-inflammatory properties and the term 'non-steroidal anti-inflammatory drug' was first used when phenylbutazone was introduced 3 years later. Since then, the NSAIDs have proliferated. There is to date no good evidence that they halt progression of rheumatoid disease, but by easing pain and diminishing swelling they make life much easier in osteoarthrosis, rheumatoid arthritis and many other types of arthritis, and are the drugs of first choice in acute gout. Their mode (or modes) of action are obscure and though inhibition of cyclo-oxygenase (prostaglandin synthetase) is clearly important, other mechanisms are also involved. The assessment of the anti-inflammatory action of these agents has received considerable attention in clinical trials because, whatever their action may be in experimental animal models, their action in inflamed joints in human patients must be ascertained, since there may be little parallel between the two. Different experimental animal models give different results with various agents and often bear little relation to their therapeutic action in man. No attempt has been made here to review in depth all the NSAIDs that have appeared since 1952. All have anti-inflammatory and analgesic activity and all can cause gastrointestinal side effects, though effectiveness and toxicity vary from drug to drug and patient to patient, there being very great interpatient variability. Non-reactors, patients who apparently fail to respond to certain agents, need further study, for it seems that these subjects may metabolise these agents differently from others. Considerable ingenuity has been shown not only in evolving new NSAIDs but in finding new ways of administering them. The number and variety of NSAIDs in their various forms varies greatly from country to country, depending largely on the regulatory bodies of those countries. In the meantime, the search for a better, less toxic compound continues with the hope that one may be found which has a deeper and more basic action on the underlying disease process.

Combined effects of diflunisal and nifedipine on uterine contractility in dysmenorrhoeic patients

In eight nulliparous women with severe primary dysmenorrhoea, intrauterine pressure was recorded on the first day of menstruation before and after administration of diflunisal 1000 mg. Uterine activity was significantly decreased in all patients but abolished in none. Seven women experienced almost complete relief of pain. To four of the patients, including the one who did not become pain-free after diflunisal, nifedipine 30 mg was also given. Uterine activity was abolished in all, but the patient not responding to diflunisal had persistent pains. It is suggested that diflunisal may be used for treatment of pain in primary dysmenorrhoea. Addition of nifedipine can produce a further decrease in uterine activity, but whether combined therapy may offer therapeutic advantages remains to be established.

Piroxicam: a review of its pharmacological properties and therapeutic efficacy

Piroxicam is an N-heterocyclic carboxamide of 1,2 benzothiazine 1,1 dioxide with analgesic and anti-inflammatory activity. It has an extended half-life of about 40 hours and is suitable for once daily administration. Published studies indicate that piroxicam 20mg daily is comparable with aspirin 3 to 6g. indomethacin 75 to 150mg, phenylbutazone 400mg, naproxen 500mg, ibuprofen 1200 to 2400mg and diclofenac 75mg in rheumatoid arthritis. In osteoarthritis, piroxicam 20mg daily is comparable in efficacy with aspirin 2.6 to 3.9g, indomethacin 75mg, naproxen 500mg and fenbufen 600mg but is generally better tolerated than aspirin or indomethacin in patients with arthritic diseases. Piroxicam 20mg was at least as effective as indomethacin 75mg in a study in ankylosing spondylitis. As with other non-steroidal anti-inflammatory drugs gastrointestinal complaints are the most frequently reported side effects and their frequency and severity appears to be dose-related.