Comparative analgesic effects of naproxen sodium, aspirin, and placebo

Therapeutic uses of non-steroidal anti-inflammatory drugs in dentistry

The non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used classes of drugs for the management of acute and chronic pain in dentistry. Their therapeutic efficacy and toxicity are well-documented and provide evidence that NSAIDs generally provide an acceptable therapeutic ratio of pain relief with fewer adverse effects than the opioid-mild analgesic combination drugs that they have largely replaced for most dental applications. The great many studies done with the oral surgery model of acute pain indicate that a single dose of an NSAID is more effective than combinations of aspirin or acetaminophen plus an opioid, with fewer side-effects, thus making it preferable for ambulatory patients. The combination of an NSAID with an opioid generally results in marginal analgesic activity but with an increased incidence of side-effects, which limits its use to patients in whom the NSAID alone results in inadequate analgesia. The selective COX-2 inhibitors hold promise for clinical efficacy with less toxicity from chronic administration and may prove advantageous for the relief of chronic orofacial pain. The use of repeated doses of NSAIDs for chronic orofacial pain should be re-evaluated in light of a lack of documented efficacy and the potential for serious gastrointestinal and renal toxicity with repeated dosing.

The clinical effect of naproxen sodium after arthroscopy of the knee: a randomized, double-blind, prospective study

The aim of this study was to examine the clinical effect of naproxen sodium after knee arthroscopy. The design was randomized, prospective, and double-blind, with a placebo control group. Patients with preoperative synovial reaction were excluded. One hundred twenty consecutive arthroscopies were performed in 77 men and 43 women, median age 34 (range 18-65) years. General anesthesia was used. Ninety-one arthroscopies were operative, whereas 29 were diagnostic. Postoperatively the patients received either 550 mg naproxen sodium twice daily or placebo for 10 days. Patients were given 500 mg acetaminophen to use if needed. Clinical examinations were performed 10 and 20 days postoperation. The results were analyzed using the Mann-Whitney test and chi 2 test. No operative complications were registered. All but two patients completed the study. Six patients had slight gastrointestinal symptoms. At 10 days' follow-up, in patients who had undergone operative arthroscopy naproxen sodium demonstrated a statistically significant effect on synovial effusion (p < 0.01), range of motion (p < 0.001), quadriceps strength (p < 0.05), pain (p < 0.001), walking activity (p < 0.05), and use of crutches (p < 0.01). In patients who had undergone diagnostic arthroscopy naproxen sodium demonstrated a beneficial effect on pain (p < 0.01). At 20 days' follow-up, in the operative group naproxen sodium affected synovial effusion (p < 0.05), range of motion (p < 0.01) and pain (p < 0.05), and walking activity (p < 0.05). No effect was seen in the diagnostic group at 20 days' follow-up.

The comparative efficacy of naproxen sodium and pirprofen in the treatment of post-operative pain

A randomized, single-blind, parallel study involving 100 adults was performed to compare the efficacy and safety of naproxen sodium with that of pirprofen in the treatment of moderate to severe pain after orthopaedic surgery. Fifty patients received 550 mg of naproxen sodium initially and 275 mg every 6 h thereafter, and 50 received 400 mg of pirprofen every 8 h until either their pain was completely relieved or the 3-day trial ended. Patients who required additional analgesia were given 500 mg of paracetamol 2 h after administration of the test medication. Both medications significantly relieved post-operative pain, and there were no statistically significant differences in efficacy between the groups. Six patients receiving naproxen sodium and two patients receiving pirprofen withdrew from the study because of lack of efficacy. Thirteen patients receiving naproxen sodium recorded 17 adverse events and 13 patients receiving pirprofen recorded 20 adverse events, again with no statistically significant differences between groups. Six patients in each group withdrew from the study because of these adverse events. Naproxen sodium and pirprofen were equally safe and effective in relieving post-operative pain following musculoskeletal surgery.

Analgesic effect of naproxen sodium, codeine, a naproxen-codeine combination and aspirin on the postoperative pain of oral surgery

In a double-blind study, 198 outpatients with pain after oral surgery were randomly assigned to treatment with a single oral dose of naproxen sodium 550 mg, codeine sulfate 60 mg, a combination of naproxen sodium 550 mg with codeine sulfate 60 mg, aspirin 650 mg or placebo. Using a self-rating record, subjects rated their pain and its relief hourly for 12 hours after medication. Orthogonal contrasts for the four treatments making up the factorial component showed that the naproxen effect was significant for every measurement of total and peak analgesia; the codeine effect was significant for total and peak pain relief and patients' overall evaluation. The naproxen-codeine interaction was not statistically significant for any measure, which suggests that the analgesic effect of the combination represents the additive effect of its constituents. Based on pairwise comparisons, aspirin was significantly superior to placebo for most measures of effect, naproxen was significantly superior to both aspirin and codeine for all measures and the combination was significantly superior to naproxen for patients' overall evaluation. No more patients experienced adverse effects with aspirin or naproxen than with placebo, but significantly more patients receiving the codeine-containing treatments experienced adverse effects than those receiving aspirin and naproxen.

Peripherally acting analgesics

The therapeutic effect of aspirin and the other nonsteroidal anti-inflammatory drugs derives from the peripheral inhibition of prostaglandin synthetase. Aspirin produces irreversible inhibition, whereas the inhibition triggered by the other nonsteroidal anti-inflammatory drugs is reversible. Despite proved analgesic efficacy, use of aspirin and the nonsteroidal anti-inflammatory drugs may be accompanied by a wide range of side effects of a potentially serious nature. For relief of pain, there appears to be no clear-cut superiority of one nonsteroidal anti-inflammatory drug over another, and patients who fail to respond to one class of nonsteroidal anti-inflammatory drugs may respond to a representative of another class. As with aspirin, it is difficult to demonstrate the superiority of higher doses of these agents over the lower doses. The side-effect profile of non-narcotic analgesics favors acetaminophen, presumably because its inhibition of prostaglandin synthetase occurs centrally. Acetaminophen does not appear to have the same potential for toxicity that is seen with aspirin and other nonsteroidal anti-inflammatory drugs. At dosages up to 4 g per day, acetaminophen compares favorably in analgesic potency to aspirin and other nonsteroidal anti-inflammatory drugs, and it should be considered the treatment of choice for mild-to-moderate pain. Safe conditions for the analgesic use of nonsteroidal anti-inflammatory drugs in children and pregnancy have not been established. Because it is virtually free of side effects, acetaminophen may be the mild analgesic of choice for the pregnant patient. It has been used safely for years in children. Only a limited number of analgesic studies have been conducted in children. The results of analgesic studies carried out in adults are generally recognized as applicable to pain relief in children.

Effects of a combination of oral naproxen sodium and codeine on experimentally induced pain

The effect of an orally administered combination of naproxen sodium 550 mg and codeine phosphate 60 mg on threshold and tolerance to electrically induced pain, and on the threshold to thermally induced pain, was compared with the effects of naproxen sodium 550 mg alone, codeine phosphate 60 mg alone, and placebo. 16 female and 16 male, healthy young subjects, took part in four experiments on consecutive days of one week. On each day one treatment was administered, in random order, under double blind conditions. The combination increased threshold and tolerance to electrically induced pain and the threshold thermally induced pain markedly more than did naproxen sodium alone. Naproxen sodium plus codeine was also more effective in increasing threshold and tolerance to electrically induced pain than was codeine alone; the latter increased the threshold and tolerance to electrically induced pain and the threshold to thermally induced pain markedly more than placebo. Naproxen sodium alone had a relatively weak effect on the three pain measures. Reaction time to acoustic stimuli and the side effect profile were not significantly influenced by any of the treatments, and no severe adverse effects occurred. It is concluded that the combination of naproxen sodium 550 mg and codeine phosphate 60 mg, as indicated by its effects on experimentally induced pain, can produce more intense analgesia than the same doses of naproxen sodium and codeine administered alone, and that naproxen sodium and codeine phosphate given in combination enhanced each other's effect in an additive manner.

A single-dose analgesic study of naproxen sodium and soluble aspirin in patients with rheumatoid arthritis

Nineteen patients with moderate or severe pain due to rheumatoid arthritis were entered into a double-blind, crossover comparison of single doses of 550 mg naproxen sodium and 900 mg soluble aspirin. Pain relief, measured on a visual analogue scale, showed a rapid onset of action of both drugs. Pain relief reached 50% of its maximum within 1 hour on both drugs. There were no significant differences in the pain relief/time curves. Five patients found no relief of pain with either drug but of the remaining 14 patients 10 reported an onset of action of both drugs within half an hour. Nine patient on naproxen sodium and 7 on soluble aspirin rated pain relief as good or very good. At the end of the study, 7 patients preferred soluble aspirin, 4 preferred naproxen sodium and the remainder gave no preference. There were no side-effects on eigher drug.

A comparison of the efficacy of naproxen sodium and a paracetamol/dextropropoxyphene combination in the treatment of soft-tissue disorders

Ninety-eight patients were admitted to a single-blind parallel study comparing the efficacy of naproxen sodium with a paracetamol/dextropropoxyphene combination in the treatment of soft-tissue disorders. The two study groups were well matched in all respects. After seven days of treatment patients in the naproxen sodium group had less residual symptoms and more of them were considered cured. These patients also had a significantly lower mean-pain-score, tended to have less daily symptoms and recorded a significantly greater initial improvement in their condition. Fewer side-effects were recorded by the naproxen sodium-treated patients. One patient from each group withdrew from the study because of side-effects. It was concluded that in the treatment of non-articular soft-tissue disorders the use of a rapidly-acting withdrew anti-inflammatory drug, naproxen sodium, gave a better clinical response than did treatment with a simple analgesic combination.

Bioavailability of naproxen sodium and its relationship to clinical analgesic effects

1 In the first of a series of trials with naproxen sodium it was shown that patients achieved significantly earlier and higher plasma levels of naproxen when naproxen sodium was administered. 2 In a second study comparing naproxen with naproxen sodium in patients with post-partum pain, pain intensity was consistently lower for the group receiving naproxen sodium. However, statistically significant differences were not seen until 4 to 5 h after medication. 3 A final study documented that a more frequent dosage schedule of every 6 h led to clearly higher plasma levels than those achieved with an every 8 h regimen; plasma levels did not plateau. Doses up to 1,375 mg/day were well tolerated. 4 In conclusion, naproxen sodium appears to be an improved form of naproxen for use as a analgesic agent.