Antinociceptive effects of S(+)-ketoprofen and other analgesic drugs in a rat model of pain induced by uric acid

We investigated the antinociceptive properties of dexketoprofen trometamol [S(+)-ketoprofen tromethamine salt; SKP], a new analgesic, antiinflammatory drug, using the pain-induced functional impairment model in the rat (PIFIR), an animal model of arthritic pain. SKP was compared with racemic ketoprofen tromethamine salt (rac-KP), R(-)-ketoprofen tromethamine salt (RKP), ketorolac (KET), and morphine (MOR). We also assessed the effects of flurbiprofen (rac-FB) and its enantiomers (SFB and RFB) in the same model. Groups of six rats received either vehicle or analgesic drug and antinociception was evaluated by evaluating the dose-response curves over time. SKP was an effective antinociceptive drug in this model and was almost equally potent by either oral or intracerebroventricular administration. The oral potency of SKP was similar to that of oral KET and greater than that of oral MOR. No significant differences were observed between racemic ketoprofen and its enantiomers when administered orally. In the rat, significant bioinversion of RKP to SKP occurs when RKP is given orally. After oral administration of RKP, SKP was detectable in 30 min and surpassed the concentration of RKP after 3 h. Nevertheless, when the compounds were given intracerebroventricularly, some stereoselectivity in favor of SKP was observed. Stereoselectivity was observed with flurbiprofen, an analogue of ketoprofen that does not undergo significant metabolic inversion. Whereas SFB was an effective antinociceptive, RFB had no antinociceptive effect at the doses tested when given either orally or intracerebroventricularly.

The opioid-sparing effects of intravenous ketorolac as an adjuvant analgesic in cancer pain: application in bone metastases and the opioid bowel syndrome

Side effects of morphine are common when given in titrated doses to control severe pain in advanced cancer. We report a case series of acutely ill cancer patients suffering from pain, complications of advanced disease, and opioid side effects. They were treated with intravenous (i.v.) ketorolac along with i.v. morphine using repeated dosing. Excellent pain relief with improvement in the opioid bowel syndrome was achieved. We found it possible to switch from IV ketorolac to oral ketorolac along with oral morphine for long-term pain control. Ketorolac can be well tolerated in high-dose, long-term use even in this frail patient population. An algorithm is presented for the suggested use of ketorolac as a morphine sparing agent. Potential methods for studying ketorolac further in this role are discussed.

Effect of intra-articular versus systemic anti-inflammatory drugs in a rabbit model of temporomandibular joint inflammation

PURPOSE

In an attempt to better understand the time course of inflammatory mediator production or release in inflammatory joint disease, a rabbit model of acute temporomandibular joint (TMJ) inflammation was established. This model was used to evaluate the effects of specific anti-inflammatory agents administered either systemically (intraperitoneal, IP) or locally (intra-articular, IA) on the modulation of in vivo tissue levels of two prototypic inflammatory mediators, prostaglandin E2 (PGE2) and bradykinin (BK).

MATERIALS AND METHODS

An experimental model of inflammation was created by administering carrageenan (carra) into one joint and an equivalent volume of saline (control) into the contralateral joint of 42 male New Zealand White rabbits. The development of hyperthermia was assessed by placement of a microthermister probe into the joint space. The inflammatory mediators, immunoreactive PGE2 (iPGE2) and BK (iBK), were recovered with microdialysis probes, and samples were assayed in conjunction with specific pharmacologic interventions. In the first part of the study, the time course for the release or production of iBK and iPGE2 was determined. In the second part, the effects of IP versus IA administration of dexamethasone and a nonsteroidal anti-inflammatory drug, ketorolac tromethamine, were compared. Dexamethasone and ketorolac were administered at 3 hours and 1 hour, respectively, before the peak release of the inflammatory mediators.

RESULTS

The onset of IA hyperthermia, an index of inflammation, was evident by 90 minutes post-carra and reached a maximum of 1.2 degrees C above core temperature by 150 minutes post-carra. Intra-articular levels of iPGE2 and iBK peaked at 240 minutes (3.35+/-1.9 nmol/L) and 270 minutes (0.45+/-0.29 nmol/L), respectively, after the induction of inflammation in the superior joint space. iBK levels within the superior joint space were significantly decreased by dexamethasone and ketorolac. Ketorolac (50 microg) decreased iBK and iPGE2 levels when given IA or IP. With dexamethasone (3 mg), the levels of iBK were significantly reduced, and iPGE2 levels were not changed.

CONCLUSIONS

This study shows that the rabbit model of TMJ inflammation, with concurrent collection of iBK and iPGE2 via microdialysis, is a reproducible and reliable method to investigate the time course of inflammatory mediator release and their modulation by either the local or systemic administration of anti-inflammatory medications.

Low-dose intra-articular ketorolac for pain relief following arthroscopy of the knee joint

The systemic administration of nonsteroidal anti-inflammatory agents has been shown to improve analgesia following arthroscopy of the knee joint. Ketorolac 60 mg, when given intra-articularly, provides better postoperative analgesia than an identical dose administered systemically. We compared the postoperative analgesic effect of ketorolac 10 mg given intravenously with 5 mg intra-articularly in 60 patients undergoing arthroscopy of the knee joint under general anaesthesia. Patients were randomly allocated in a double-blind manner to receive 0.25% bupivacaine 20 ml and ketorolac 5 mg intra-articularly (n = 27) or intravenous ketorolac 10 mg followed by 0.25% bupivicaine 20 ml (n = 30) at the end of surgery. There were no differences between the groups in terms of their physical characteristics or in the nature of procedure performed. There was no statistical difference between the two groups in time to first analgesia or postoperative visual analogue pain scores at 1, 2 and 4 h (p = 0.6). The median consumption of a standard analgesic was reduced in the intra-articular group in the second 24-h period but this did not achieve statistical significance (p = 0.08). Only five patients in total needed postoperative morphine. A reduced amount of locally applied ketorolac (5 mg) provides similar analgesia to a higher systemic dose (10 mg) following knee arthroscopy.

A comparative study of ketorolac (Toradol) and magnesium sulfate for arrest of preterm labor

BACKGROUND

We evaluated the efficacy and safety of ketorolac (Toradol).

METHODS

In this prospective trial, 88 women in confirmed preterm labor at < or =32 weeks' gestation were randomized to receive magnesium sulfate given as an initial 6 g intravenous bolus followed by continuous infusion therapy (2 to 6 g/hr) or intramuscularly administered ketorolac (60 mg loading dose) followed by 30 mg every 6 hours for a maximum of 24 hours.

RESULTS

The study groups were similar with respect to age, parity, cervical status, and gestational age on admission. Ketorolac was more rapid (2.71 hr+/-2.16) in the arrest of preterm labor than was magnesium sulfate (6.22 hr+/-5.65). No patient required discontinuance of either drug due to adverse effects. There was no difference in the incidence of neonatal complications between the two groups.

CONCLUSION

In gestations with preterm labor at <32 weeks, ketorolac appears to be an appropriate first-line tocolytic agent.

Effects of ketorolac and dextran-70 alone and in combination on haemostasis

BACKGROUND

Dextran may be used in surgical patients for thromboprophylaxis or volume expansion along with ketorolac, a nonsteroidal anti-inflammatory drug, for analgesia. As these two agents can influence the haemostatic system at different sites, it is important to demonstrate that there is no adverse haemostatic interaction between them.

METHODS

The haemostatic interaction between intravenous dextran-70 and intramuscular ketorolac was assessed in a double-blind, randomised, crossover study of healthy male volunteers each given all four combinations of ketorolac/placebo intramuscularly and dextran/placebo intravenously. The effect of ketorolac and dextran on haemostasis was assessed by the following techniques: skin bleeding time, in vitro platelet aggregation function, whole blood thromboxane generation, von Willebrand factor antigen, factor VIII coagulant activity and tissue plasminogen activator. The results were analysed for the effects of ketorolac and dextran and for any evidence of an interaction.

RESULTS

Ketorolac inhibited platelet function and thromboxane generation. Dextran reduced factor VIII coagulant activity. Neither agent had a significant effect on bleeding time, von Willebrand factor or tissue plasminogen activator. There was only evidence of a small but statistically significant interaction between ketorolac and dextran on thromboxane generation. There was no evidence of any other interaction of ketorolac with dextran.

CONCLUSION

This interaction on thromboxane generation is unlikely to be of clinical significance as substantial inhibition of thromboxane generation occurs with ketorolac alone.

Comparative effects of ketorolac 0.5% or diclofenac 0.1% ophthalmic solutions on inflammation after cataract surgery

OBJECTIVE

Ketorolac tromethamine 0.5% and diclofenac sodium 0.1% ophthalmic solutions are approved for use by the U.S. Food and Drug Administration to avoid excessive postoperative inflammation after cataract surgery and implantation of an intraocular lens. This study compares the efficacy and toxicity of these nonsteroidal anti-inflammatory drugs for the first time.

DESIGN

Randomized, double-masked, prospective clinical trial.

PARTICIPANTS

A total of 120 patients assigned in equal numbers to 1 of the 2 treatment regimens.

INTERVENTION

Treatment with either ketorolac 0.5% or diclofenac 0.1% ophthalmic solutions instilled four times daily for 30 days beginning the first postoperative day after surgery.

MAIN OUTCOME MEASURES

Objective (Kowa FC 1000 laser cell and flare meter) and subjective (slit-lamp biomicroscope) measurements of inflammation and toxicity were made and compared at three separate post-operative visits.

RESULTS

The anti-inflammatory effects of the two treatment regimens were not statistically different at any of the postoperative visits. Patients tolerated both treatments equally well.

CONCLUSIONS

This study shows diclofenac sodium 0.1% and ketorolac tromethamine 0.5% ophthalmic solutions are equally effective and safe for the control of postoperative inflammation after uncomplicated cataract surgery performed by phacoemulsification followed by the implantation of a foldable intraocular lens.

Analgesic efficacy and safety of preoperative versus postoperative ketorolac in paediatric tonsillectomy

BACKGROUND

Tonsillectomy is a common procedure in childhood resulting in significant morbidity due to pain. The aim of this study was to evaluate the analgesic efficacy and safety of a single dose of ketorolac i.v. given before or after tonsillectomy, compared to placebo.

METHODS

A randomized, double-blind, placebo-controlled study was performed in 60 children, 5 to 15 years of age, admitted for tonsillectomy. Patients were allocated to receive ketorolac 1 mg.kg-1 i.v. or placebo. Postoperative pain was assessed by self-report 1.5, 3, 5, and 24 h after surgery.

RESULTS

Pain scores were significantly lower for both ketorolac groups compared to the placebo group 1.5, 3, and 5 h after surgery (P = 0.05). Pain scores were lowest in the preoperative ketorolac group 1.5 to 5 h after surgery, and significantly fewer children in this group had fentanyl 0 to 1.5 hr after surgery. But no significant differences were found between pain scores of the preoperative and postoperative ketorolac groups in the first 24 h after surgery. Acetaminophen consumption during the first 5 h after surgery was significantly less in patients receiving ketorolac (P < 0.05). Patients in the preoperative ketorolac group had a significantly lower incidence of postoperative vomiting (P < 0.05). There were no significant differences in the incidence of postoperative bleeding between groups. Three children in the preoperative, 5 children in the postoperative ketorolac group and 5 children in the placebo group experienced postoperative haemorrhage.

CONCLUSION

This study indicates that a single dose of ketorolac 1 mg.kg-1 i.v. administered either before or immediately after surgery improves postoperative analgesia in children after tonsillectomy without evidence of increased incidence of bleeding.

A randomized double-masked trial comparing ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, and prednisolone acetate 1% in reducing post-phacoemulsification flare and cells

BACKGROUND AND OBJECTIVE

To compare the efficacy of ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, and prednisolone acetate 1% in reducing flare and cells following cataract surgery.

PATIENTS AND METHODS

Fifty-eight patients undergoing phacoemulsification with posterior chamber intraocular lens implantation were randomly selected to receive either ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, or prednisolone acetate 1% following surgery. The treatment regimen was 1 drop 4 times a day for 1 week, then twice a day for the next 3 weeks. Flare, cells, and intraocular pressures (IOPs) were measured preoperatively and on postoperative days 1, 7, and 28.

RESULTS

No statistically significant differences in either actual flare or cell counts or in change in flare or cell counts from baseline were detected among the three groups. No statistically significant differences in IOP or in change of IOP from preoperative measurements were detected. No medication-related complications were noted at any time.

CONCLUSION

Ketorolac tromethamine 0.5% and diclofenac sodium 0.1% may be as effective and as safe as prednisolone acetate 1% in controlling inflammation following cataract extraction.

Intravenous ketorolac vs intravenous prochlorperazine for the treatment of migraine headaches

OBJECTIVE

To compare i.v. ketorolac with i.v. prochlorperazine as the initial treatment of migraine headaches in the ED.

METHODS

A prospective, double-blind comparison study was performed, using a convenience sample of 64 patients suffering from migraine headaches presenting to the ED at a tertiary care university teaching hospital. Patients were randomly assigned to receive either 10 mg of prochlorperazine i.v. or 30 mg of ketorolac i.v.. Patients scored the severity of their headaches using a 10-cm visual analog pain scale. An initial mark was made on the scale at the time of entry into the study and later another mark was made on a new unmarked pain scale 1 hour after medication administration. Changes in pain scores within each treatment group and between groups were analyzed using the Wilcoxon rank sum test.

RESULTS

Prior to treatment, the patients assigned to receive prochlorperazine had a median score of 9.2 cm (mean +/- SD pain score of 8.3 cm +/- 2.1 cm), while the patients receiving ketorolac had a median score of 9.0 (mean pain score of 8.4 cm +/- 1.7 cm). There was no significant difference between the pain scores of the participants in the 2 groups prior to treatment (p = 0.80). One hour after medication administration, the patients in the prochlorperazine group had a median score of 0.5 cm (mean 2.1 +/- 3.2 cm), while those patients receiving ketorolac had a median pain score of 3.9 (mean 4.0 +/- 3.3 cm). The decrease in pain score was significant for both groups of patients (p = 0.0001). The change in pain score for the patients in the prochlorperazine group (median 7.1) was significantly greater than the change in pain score for the patients in the ketorolac group (median 4.0; p = 0.04).

CONCLUSION

Although both drugs were associated with a significant reduction in pain scores, benefit over a placebo agent was not tested. Furthermore, the patients who received prochlorperazine i.v. for migraine headaches had a statistically significant greater decrease in their pain scores than did those receiving ketorolac i.v.

A double-blind study comparing two single-dose regimens of ketorolac with diclofenac in pain due to cancer

STUDY OBJECTIVE

To compare the analgesic efficacy and safety of two single doses of ketorolac with diclofenac in acute cancer pain.

DESIGN

Double-blind, randomized, clinical study.

SETTING

Hospital-based clinical research center.

SUBJECTS

One hundred eighty patients suffering acute, moderate, or severe cancer pain.

INTERVENTIONS

A single intramuscular injection of ketorolac 10 or 30 mg or diclofenac 75 mg.

MEASUREMENTS AND MAIN RESULTS

Pain intensity was assessed 30 minutes and 1, 2, 3, 4, 5, and 6 hours after injection or until rescue drug administration. In approximately 70% of patients all treatments provided prompt sustained pain relief throughout the 6-hour observation period. There were no statistically significant differences in any of the analyzed efficacy measures among the three groups.

CONCLUSION

Intramuscular ketorolac 10 mg is adequate to relieve cancer pain, and is equivalent to ketorolac 30 mg and to diclofenac 75 mg.

Transurethral microwave thermotherapy: strategies to ensure successful outcomes with Prostasoft 2.0

Transurethral microwave thermotherapy (TUMT) is a unique and promising method of treating benign prostatic hyperplasia. Clinical outcomes are related to thermal dose delivered. In 359 consecutive patients, strategies to increase thermal dose using the FDA-approved Prostasoft 2.0 delivered a mean of 148 kJ, which was almost 50 kJ more than the U.S. FDA trials. These strategies include careful preoperative patient teaching, exclusion of very small prostates, ketorolac, prewarming of the prostaprobe, antitorque of the rectal probe, use of urethral cooling adjustment during power ramping, and no manual power interruptions. Clinical outcomes improved without any significant adverse events. Peak urinary flow increased in 4 months by 5.5 mL/sec.

The effect of postoperative nonsteroidal anti-inflammatory drug administration on spinal fusion

STUDY DESIGN

The influence of ketorolac on spinal fusion was studied in a retrospective review of 288 patients who underwent an instrumented spinal fusion.

OBJECTIVE

To assess the effect of postoperative ketorolac administration on subsequent fusion rates.

SUMMARY OF BACKGROUND DATA

Nonsteroidal anti-inflammatory drugs are widely used compounds, which are known to inhibit osteogenic activity and have been shown to decrease spinal fusion in an animal model. No previous studies have examined the influence of nonsteroidal anti-inflammatory drugs on spinal fusion in clinical practice.

METHODS

The medical records of 288 patients who underwent instrumented spinal fusion from L4 to the sacrum between 1991 and 1993 were reviewed retrospectively. The 121 patients who received no nonsteroidal anti-inflammatory drugs were compared with the 167 patients who received ketorolac after surgery. The groups were demographically equivalent.

RESULTS

Ketorolac had a significant adverse effect on fusion, with five nonunions in the nondrug group and 29 nonunions in the ketorolac group (P > 0.001). Ketorolac administration also significantly decreased the fusion rate for subgroups including men, women, smokers, and nonsmokers. The odds ratio demonstrated that nonunion was approximately five times more likely after ketorolac administration. Cigarette smoking also decreased the fusion rate (P > 0.01); smokers were 2.8 times more likely to develop nonunion.

CONCLUSION

These data suggest that nonsteroidal anti-inflammatory drugs significantly inhibit spinal fusion at doses typically used for postoperative pain control. The authors recommend that these drugs be avoided in the early postoperative period.

The dose-response relationship of ketorolac as a component of intravenous regional anesthesia with lidocaine

Ketorolac (K) is a useful addition to lidocaine for i.v. regional anesthesia (IVRA). However, the minimal dose of K that is effective for this purpose has not been established. We added 0, 5, 10, 15, 20, 30, and 60 mg of K to 0.5% lidocaine IVRA for either carpal tunnel release or tenolysis. Pain was assessed in the postanesthesia care unit by using a visual analog scale. The duration of analgesia (time to first request for pain relief) and the use of Tylenol No. 3 tablets (T3) were measured. A linear dose-response relationship was observed between the dose of K and the duration of analgesia (r = 0.988) up to 20 mg of K. Similarly, the number of T3 tablets used was inversely related to the dose of K (r = 0.960) over the same range. There were no significant differences among the groups who received 20, 30, or 60 mg of K. We conclude that 20 mg of K is the optimal dose for inclusion with 0.5% lidocaine for IVRA under the conditions of our study.

IMPLICATIONS

The antiinflammatory drug ketorolac is a useful addition to lidocaine for i.v. regional anesthesia. This study showed that 20 mg of ketorolac is equally effective as 60 mg in this context. However, smaller doses provided less effective pain relief, and a linear dose-response relationship was demonstrated.

Preemptive pain control in patients having laparoscopic hernia repair: a comparison of ketorolac and ibuprofen

OBJECTIVES

To determine if nonsteroidal anti-inflammatory drugs provide adequate pain control for patients having laparoscopic hernia repair and to compare the effectiveness of ketorolac tromethamine with ibuprofen in reducing postoperative laparoscopic hernia pain.

DESIGN AND SETTING

Prospective double-blind randomized study at a 100-bed community hospital.

PATIENTS

Seventy patients ranging in age from 16 to 83 years scheduled for elective laparoscopic inguinal hernia repair.

INTERVENTIONS

Patients undergoing laparoscopic hernia repair were enrolled in a double-blind randomized study to compare the 2 treatments. Group 1 received a placebo capsule 1 hour before surgery and ketorolac tromethamine, 60 mg intravenously, at the time of trocar insertion. Group 2 received ibuprofen, 800 mg an hour before surgery, and isotonic sodium chloride solution, 2 mL intravenously, at the time of trocar insertion. In addition, all patients received local infiltration of 30 mL of bupivacaine hydrochloride into their trocar sites. All patients were discharged within 5 hours of the operation and were instructed to take 400 mg of ibuprofen orally every 4 hours for 24 hours whether or not they were experiencing pain. A 24-hour supply of ibuprofen was provided to all study patients. Pain was assessed using the Visual Analog Pain Scale with a maximum pain rating of 100. Assessments were done at the time of and 18 hours after discharge.

MAIN OUTCOME MEASURE

Postoperative pain 18 and 24 hours after discharge was assessed using a standardized questionnaire in a telephone interview by a registered nurse from the Outpatient Surgical Unit.

RESULTS

There was no significant difference in the level of pain experienced by 35 patients who received ketorolac intravenously and 35 who received ibuprofen orally. There was no significant difference between the 2 treatment groups in the amount of pain experienced at discharge and 18 hours after discharge.

CONCLUSIONS

Pain relief from ibuprofen, 800 mg, administered orally an hour before laparoscopic hernia repair was not statistically different from that obtained with intravenous ketorolac, 60 mg, administered intraoperatively when comparing the hospital discharge pain score and the mean and highest pain scores 18 hours after discharge. Ibuprofen offers equivalent pain control at a lower cost and reduced potential for adverse drug events compared with intravenous ketorolac in patients having laparoscopic hernia repair. No patient required narcotic supplementation, and pain control was judged satisfactory by all the patients.

A multicenter comparison of the ocular efficacy and safety of diclofenac 0.1% solution with that of ketorolac 0.5% solution in patients with acute seasonal allergic conjunctivitis

Only one of several available ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) is currently FDA approved for use in acute seasonal allergic conjunctivitis (SAC). Sixty patients with SAC and moderate itching and bulbar conjunctival injection were enrolled in a multicenter, randomized, double-masked, parallel-group trial comparing diclofenac sodium (DS) with ketorolac tromethamine (KT). Patients instilled 1 drop four times daily while awake for 14 days. Ocular signs and symptoms were evaluated at one and two weeks. The primary efficacy variables were itching and bulbar conjunctival injection. For both treatments, the ocular allergy sign and symptom scores were comparable at baseline. Both treatments evaluated in this study were well tolerated. Significant clinical and statistical reductions from baseline were observed in the primary efficacy variables. Treatment group differences were observed for the pain/soreness score with an advantage observed for the DS group at 30 minutes and at day 7. Our conclusion is that diclofenac sodium and ketorolac tromethamine acted similarly to reduce the ocular signs and symptoms associated with acute seasonal allergic conjunctivitis. There was a statistically significant advantage for the DS group to be free of symptoms at the day 7 visit as compared to the KT group (20.7% vs. 3.2%).

Analgesic efficacy and safety of nonpreserved ketorolac tromethamine ophthalmic solution following radial keratotomy. Ketorolac Radial Keratotomy Study Group

PURPOSE

To compare the analgesic efficacy and safety of nonpreserved ketorolac tromethamine 0.5% with those of its vehicle in the treatment of postsurgical ocular pain following radial keratotomy.

METHODS

This study employed a multicenter, double-masked, randomized, parallel-group design. Radial keratotomy patients were treated with either nonpreserved ketorolac tromethamine 0.5% or its vehicle four times daily for up to 3 days following surgery. Patients were provided with an escape medication (acetaminophen) for use only as needed for intolerable pain.

RESULTS

Patients treated with ketorolac reported significantly greater pain relief (P < or =.023), less pain intensity (P < or =.047), less use of escape medication (P < or =.001), fewer symptoms of ocular discomfort (P=.024), and fewer sleep disturbances (P < or =.013) than did patients treated with vehicle. No treatment-related adverse events were reported in the ketorolac group, and only one treatment-related adverse event was reported in the vehicle group. Most other safety findings were equivalent in the two treatment groups except that there were significantly less eyelid erythema (P=.026) and eyelid edema (P < or =.001) in the ketorolac group.

CONCLUSIONS

Nonpreserved ketorolac tromethamine 0.5% ophthalmic solution was significantly more effective than, and as safe as, vehicle in the treatment of postoperative pain associated with radial keratotomy. Therefore, topical ketorolac may be a valuable treatment option for the maintenance of patient comfort following refractive surgery.

Efficacy of Topical Nonsteroidal Drops as Pain Relief after Excimer Laser Photorefractive Keratectomy

PURPOSE

To compare the efficacy of topical aqueous indomethacin and ketorolac for pain relief following excimer laser photorefractive keratectomy (PRK).

METHODS

We conducted a double masked, randomized trial involving 120 patients. All patients received a standard regimen of one of the trial drugs and chloramphenicol ointment to be used four times daily for 2 days. Pain levels and quality were assessed on a 10 cm linear analogue scale prior to each instillation of the topical medication with the McGill pain questionnaire. Pain threshold was evaluated using a modified State Trait Anxiety Inventory questionnaire. Patients were advised to use paracetomol for additional pain relief but were allowed to use any oral analgesic (except nonsteroidal agents) which they documented (type and quantity).

RESULTS

There was no significant difference in pain scores between the groups using indomethacin and ketoralac.

CONCLUSION

We found no significant difference between topical ketoralac and aqueous indomethacin as pain relief following excimer laser PRK. Both drugs seemed to significantly reduce pain.

Passive versus electrotransport-facilitated transdermal absorption of ketorolac

OBJECTIVE

To investigate the bioavailability (extent and rate of absorption) of ketorolac from two cutaneous absorption sources, active electrotransport and passive transdermal, and to examine the enantiomeric selectivity of bioavailability for each source.

METHODS

Based on a crossover study in 12 healthy volunteers, the extent and rate of absorption of ketorolac, delivered by a patch, were found by estimating the input rate function of the drug. For that purpose, deconvolution was used in two steps. First, intravenous data were analyzed to estimate the ketorolac disposition function, and second, postpatch data were deconvolved to estimate the unknown patch input profile given the disposition function estimated in the first step. Because the input rate function curves to be estimated for the patches may be of arbitrary shape, a spline was used to model the patch input function, whereas intravenous data were modeled with use of a sum of exponentials. Differences in the extent of absorption (F) for the four treatment-enantiomer combinations were further examined with a mixed-effect regression model, based on the sets of four individual estimates of bioavailability.

RESULTS

On average, the F value for the active electrotransport treatment, which exhibited the faster absorption rate, was four times greater than the F for the passive transdermal treatment. Further, during the passive treatment, R-ketorolac yielded an average F that is 42% greater than that for S-ketorolac and also exhibited a smaller absorption lag-time. During the active treatment, there was no important enantiomeric difference in either extent or rate of absorption.

Controlled trial of ketorolac in tension-type headache

Intramuscular ketorolac 60 mg, meperidine 50 mg plus promethazine 25 mg, and normal saline were compared in acute exacerbations of tension-type headache. Forty-one subjects (30 females and 11 males) were randomized into three groups and evaluated by the McGill Short-Form Pain Questionnaire before treatment, and 0.5, 1, 2, 3, 4, 5, and 6 hours after treatment. All three groups showed a significant treatment effect that persisted for the 6 hours of evaluation. Ketorolac treatment was significantly better than placebo at 0.5 and 1 hour by the Visual Analog Scale (VAS) and Pain Rating Index, and better than meperidine at 2 hours (by the VAS). Meperidine and placebo did not differ at any time point. Ketorolac is effective in short-term treatment of tension-type headache.

Prolonged central intravenous ketorolac continuous infusion in a cancer patient with intractable bone pain

OBJECTIVE

To report the case of a prolonged intravenous ketorolac continuous infusion given via a central line in a cancer patient with intractable bone pain.

CASE SUMMARY

A 56-year-old Hispanic man with stage IV non-small-cell lung cancer and multiple bone metastases was admitted to the hospital for intractable pain inadequately controlled at home by conventional therapy. He was treated with an intravenous continuous infusion of ketorolac 120 mg in 250 mL of NaCl 0.9% infused over 24 hours. The ketorolac was given via a central line for 14 days in addition to fentanyl patient-controlled analgesia. Over this time period the patient reported his pain to be well controlled. His requests for bolus doses of fentanyl decreased dramatically and the dose of the continuous intravenous fentanyl was reduced by 22%. In addition, the total daily dose of ketorolac was reduced following a change from intermittent bolus dosing to a continuous infusion.

DISCUSSION

The management of cancer pain secondary to bone metastasis is a difficult and challenging problem frequently encountered by the healthcare team. The use of nonsteroidal antiinflammatory drugs (NSAIDs) as adjuvant therapy is a common practice. However, many terminally ill patients are unable to take oral medications, thus limiting NSAID treatment options. Ketorolac tromethamine is approved by the Food and Drug Administration (FDA) as a parenteral NSAID. As with other NSAIDs, the risk of adverse drug reactions must be considered when using this class of medication. The FDA has approved ketorolac for the short-term (< or = 5 d) management of moderately severe acute pain that requires analgesia at the opioid level, usually in the postoperative setting. However, certain patients may benefit from long-term use exceeding the FDA-recommended guidelines of 5 days of maximum therapy.

CONCLUSIONS

A prolonged central intravenous ketorolac continuous infusion was successful in treating a cancer patient with intractable bone pain secondary to widely metastatic non-small-cell lung cancer.

Microencapsulation of ketorolac tromethamine by means of a coacervation-phase separation technique induced by the addition of non-solvent

Ketorolac tromethamine (KT) is a non-steroidal drug with potent analgesic and anti-inflammatory activity and is absorbed rapidly (Tmax < 1.0 h) with an efficiency > 87% following oral and intramuscular administration. The plasma half-life of ketorolac ranges from 1.1 to 6.0 h. Its oral bioavailability is estimated to be 80%. Ketorolac has been found 36 times more potent than phenylbutazone, approximately twice as potent as indomethacin, and three times more potent than naproxen in suppressing carrageenan-induced paw oedema in rat. In this study, microcapsules of KT were prepared by means of coacervation-phase separation technique induced by the addition of non-solvent, and release rates from microcapsules were studied. Eudragit S100 was used as the coating material. Coacervation was achieved by the addition of cyclohexane at 2 ml/min at 25 degrees C and 1:4 solvent: non-solvent ratio was used. The microcapsules were washed with cyclohexane to harden the wall and dried at room temperature. Microcapsules with core:wall ratio of 1:1 and 1:2 were prepared and the particles obtained by sieving with an average diameter of 177-500 microns were used. The yield was calculated and the release properties of KT were investigated by USP XXII paddle method and using UV spectrophotometry at 318 and 323 nm.

Lack of hepatotoxic effects of parenteral ketorolac in the hospital setting

BACKGROUND

No large controlled studies to date have examined the hepatic safety of parenteral ketorolac, which is used to treat acutely ill hospitalized patients who may be at greatest risk of liver injury.

OBJECTIVE

To measure the association between the use of parenteral ketorolac and subsequent liver injury.

METHODS

A nonexperimental cohort study conducted in 35 hospitals in the greater Philadelphia, Pa, region examined 10,272 courses of parenteral ketorolac (the exposed group) and 10,247 courses of parenteral opioid (the comparison group). Liver injury was defined by a modified international consensus definition that relied exclusively on liver function tests. Proportional hazards regression was used to calculate the rate ratio and 95% confidence interval for the association between ketorolac exposure and the occurrence of liver injury, controlling for potentially confounding factors, and to explore the possible effects of duration and dose.

RESULTS

The incidence of liver injury was 1.0% in the ketorolac group and 1.2% in the opioid group, yielding an unadjusted rate ratio of 0.77 (95% confidence interval, 0.59 1.01). Simultaneously adjusting for multiple potentially confounding factors did not change this result. There was no evidence for a duration-response relationship (P = .96) or a dose-response relationship (P = .23). We were unable to identify any subgroups that were susceptible to possible hepatotoxic effects of parenteral ketorolac.

CONCLUSIONS

This study failed to find evidence of a hepatotoxic effect of parenteral ketorolac use in the hospital setting and provides strong evidence against the existence of a clinically meaningful association between exposure to parenteral ketorolac in the hospital setting and liver injury.

Effect of ketorolac tromethamine on atracurium-induced neuromuscular blockade in anesthetized dogs

OBJECTIVE

The purpose of this study was to determine the effect of ketorolac tromethamine or placebo on the neuromuscular blockade induced by an infusion of atracurium in isoflurane-anesthetized dogs.

DESIGN

Randomized, controlled trial.

ANIMALS

Six healthy, adult mixed-breed dogs (five female, one male) weighing 24.8 +/- 2.8 kg.

METHODS

Dogs were studied on two occasions with a minimum of 7 days between studies. Dogs were induced with 5% isoflurane in oxygen and maintained with 1.6 x minimum alveolar concentration (MAC) end-tidal isoflurane. Neuromuscular blockade was assessed using the train-of-four response. Once 50% depression of the first twitch (T1) was achieved, the atracurium infusion rate was held constant for 30 minutes. Then ketorolac, 0.5 mg/kg, or the same volume of placebo (0.9% sodium chloride solution) was administered intravenously and the atracurium infusion maintained for an additional 60 minutes. Before and at 2, 5, 10, 15, 30, and 60 minutes after ketorolac or placebo, the percent depression of T1 and the fourth twitch to the first twitch (T4/T1) ratio were recorded. The atracurium infusion was discontinued and the time for T1 to recover from 50% to 75% of its original value was recorded. At 75% T1, edrophonium, 0.5 mg/kg intravenously, was administered to antagonize the residual blockade.

RESULTS

There was no significant difference in T1%, T4/T1 ratio, or recovery time after ketorolac administration compared with placebo.

CONCLUSIONS

Ketorolac, 0.5 mg/kg intravenously, has no significant effect on either atracurium-induced neuromuscular blockade or recovery time for T1 in isoflurane-anesthetized dogs.

CLINICAL RELEVANCE

The concurrent use of atracurium should not be a contraindication for the administration of ketorolac for intraoperative or postoperative analgesia.