Ketorolac. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential

Ketorolac is a non-steroidal agent with potent analgesic and moderate anti-inflammatory activity. It is administered as the tromethamine salt orally, intramuscularly, intravenously, and as a topical ophthalmic solution. Clinical studies indicate single-dose efficacy greater than that of morphine, pethidine (meperidine) and pentazocine in moderate to severe postoperative pain, with some evidence of a more favourable adverse effect profile than morphine or pethidine. In single-dose studies ketorolac has also compared favourably with aspirin, paracetamol (acetaminophen) and a few other non-steroidal anti-inflammatory drugs. If further investigation confirms the initially favourable findings regarding efficacy and tolerability, ketorolac will be a useful alternative to opioid agents in postsurgical pain. It may well also find use in acute musculoskeletal pain, where it appears at least as effective as other agents with which it has been compared. From the limited clinical data available, ketorolac also seems promising in the treatment of ocular inflammatory conditions. Additional multiple-dose studies are required to evaluate fully the potential of ketorolac in the management of chronic pain states where it has shown superior efficacy to aspirin. In summary, ketorolac offers promise as an alternative to opioid and to other nonsteroidal analgesics in ameliorating moderate to severe postsurgical pain, and with wider clinical experience may find a place in the treatment of acute musculoskeletal and other pain states, and ocular inflammatory conditions.

Ketorolac. A reappraisal of its pharmacodynamic and pharmacokinetic properties and therapeutic use in pain management

Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) with strong analgesic activity. The analgesic efficacy of ketorolac has been extensively evaluated in the postoperative setting, in both hospital inpatients and outpatients, and in patients with various other acute pain states. After major abdominal, orthopaedic or gynaecological surgery or ambulatory laparoscopic or gynaecological procedures, ketorolac provides relief from mild to severe pain in the majority of patients and has similar analgesic efficacy to that of standard dosages of morphine and pethidine (meperidine) as well as less frequently used opioids and other NSAIDs. The analgesic effect of ketorolac may be slightly delayed but often persists for longer than that of opioids. Combined therapy with ketorolac and an opioid results in a 25 to 50% reduction in opioid requirements, and in some patients this is accompanied by a concomitant decrease in opioid-induced adverse events, more rapid return to normal gastrointestinal function and shorter stay in hospital. In children undergoing myringotomy, hernia repair, tonsillectomy, or other surgery associated with mild to moderate pain, ketorolac provides comparable analgesia to morphine, pethidine or paracetamol (acetaminophen). In the emergency department, ketorolac attenuates moderate to severe pain in patients with renal colic, migraine headache, musculoskeletal pain or sickle cell crisis and is usually as effective as frequently used opioids, such as morphine and pethidine, and other NSAIDs and analgesics. Subcutaneous administration of ketorolac reduces pain in patients with cancer and seems particularly beneficial in pain resulting from bone metastases. The acquisition cost of ketorolac is greater than that of morphine or pethidine; however, in a small number of studies, the higher cost of ketorolac was offset when treatment with ketorolac resulted in a reduced hospital stay compared with alternative opioid therapy. The tolerability profile of ketorolac parallels that of other NSAIDs; most clinically important adverse events affect the gastrointestinal tract and/or renal or haematological function. The incidence of serious or fatal adverse events reported with ketorolac has decreased since revision of dosage guidelines. Results from a large retrospective postmarketing surveillance study in more than 20,000 patients demonstrated that the overall risk of gastrointestinal or operative site bleeding related to parenteral ketorolac therapy was only slightly higher than with opioids. However, the risk increased markedly when high dosages were used for more than 5 days, especially in the elderly. Acute renal failure may occur after treatment with ketorolac but is usually reversible on drug discontinuation. In common with other NSAIDs, ketorolac has also been implicated in allergic or hypersensitivity reactions. In summary, ketorolac is a strong analgesic with a tolerability profile which resembles that of other NSAIDs. When used in accordance with current dosage guidelines, this drug provides a useful alternative, or adjuvant, to opioids in patients with moderate to severe pain.

Ketorolac tromethamine as compared with morphine sulfate for treatment of postoperative pain

Ketorolac tromethamine, a nonnarcotic, prostaglandin synthesis-inhibiting analgesic, was compared with morphine sulfate for relief of moderate to severe postoperative pain. The 155 patient participants received single intramuscular doses of either ketorolac, 10, 30, or 90 mg, or morphine, 6 or 12 mg, administered in a double-blind, randomized fashion. Pain scores (verbal and visual analog) were recorded at baseline and assessed at 30 minutes and then hourly to 6 hours. Pain relief was rated at the same times. Ketorolac, 90 and 30 mg, was rated significantly better than morphine, 6 mg, at each assessment interval after 1 hour. Ketorolac, 90 and 30 mg, was rated similarly to morphine, 12 mg, for the first 3 hours and better than morphine, 12 mg, 4 hours after injection. There were no serious side effects reported. The only side effect reported in more than 3% of patients was 8% somnolence with morphine. This study shows ketorolac to be a safe and effective analgesic for relief of postoperative pain.

The morphine sparing effect of ketorolac tromethamine. A study of a new, parenteral non-steroidal anti-inflammatory agent after abdominal surgery

A randomised, double-blind study of patients after upper abdominal surgery was undertaken to assess the analgesic efficacy of ketorolac tromethamine, a new, parenteral non-steroidal anti-inflammatory agent. Postoperatively, patients received a 24-hour intramuscular infusion of either saline (n = 20), ketorolac 1.5 mg/hour (n = 21) or ketorolac 3.0 mg/hour (n = 20). Cumulative morphine requirements were measured using a patient-controlled analgesia system which delivered intravenous increments of morphine on demand. Pain was assessed by visual analogue scores. Arterial blood gas analyses were performed pre-operatively and on the first postoperative day. Patients who received low and high dose ketorolac infusions required less morphine than the control group (p less than 0.05 and p = 0.06, respectively). This was associated with significantly lower pain scores. Patients who received the higher ketorolac dose had significantly less postoperative increase in arterial carbon dioxide tensions than controls. This study suggests that ketorolac tromethamine is a useful analgesic drug with significant morphine sparing properties.

Comparison of intramuscular ketorolac tromethamine and morphine sulfate for analgesia of pain after major surgery

Ketorolac tromethamine is a new injectable nonnarcotic analgesic. In a parallel, double-blind study, the analgesic efficacies of single intramuscular doses of ketorolac 10, 30 and 90 mg were compared with those of morphine sulfate 6 and 12 mg. Two hundred forty-one patients were categorized according to type of surgical procedure and severity of pain. Pain intensity and pain relief were assessed for 6 hours by scoring standard verbal and visual analog scales. Patients receiving ketorolac 10, 30 or 90 mg or morphine (MS) 12 mg all had significantly better pain relief in almost all measurements performed than those receiving MS 6 mg (p less than 0.05). Ketorolac 10 and 30 mg were as effective as morphine 12 mg during the entire 6-hour observation period, and ketorolac 90 mg was more effective than morphine 12 mg during the entire 6 hours. Patients with pain related to major surgery (e.g., cholecystectomy and abdominal hysterectomy) were better able to distinguish analgesic potency of morphine than those having less traumatic procedures (e.g., tendon and ligament repairs).

Perioperative effects of oral ketorolac and acetaminophen in children undergoing bilateral myringotomy

Prophylactic administration of analgesics before surgery can decrease the intraoperative anaesthetic requirement and decrease pain during the early postoperative period. In a double-blind, placebo-controlled study involving 90 healthy ASA physical status I or II children undergoing bilateral myringotomy, we compared the postoperative analgesic effects of oral acetaminophen and ketorolac, when administered 30 min before induction of anaesthesia. Patients were randomized to receive saline (0.1 ml.kg-1), acetaminophen (10 mg.kg-1) or ketorolac (1 mg.kg-1) diluted in cherry syrup to a total volume of 5 ml. Anaesthesia was induced and maintained with halothane and nitrous oxide via a face mask. Postoperative pain was assessed by a blinded observer using an objective pain scale. The three study groups were similar with respect to demographic data, duration of anaesthesia and surgery, induction behaviour, oxygen saturation, incidence of postoperative emesis and, recovery times. The ketorolac group had lower postoperative pain scores and required less frequent analgesic therapy in the early postoperative period compared with the acetaminophen and placebo groups. In contrast, there were no differences in pain scores or analgesic requirements between the acetaminophen and the placebo groups. We conclude that the preoperative administration of oral ketorolac, but not acetaminophen, provided better postoperative pain control than placebo in children undergoing bilateral myringotomy.

Improvement in visual acuity in chronic aphakic and pseudophakic cystoid macular edema after treatment with topical 0.5% ketorolac tromethamine

Ketorolac tromethamine 0.5% ophthalmic solution treatment was compared to placebo treatment in 120 patients with chronic aphakic or pseudophakic cystoid macular edema (six-month or more duration of distance visual acuity of 20/40 or less and angiographic evidence of cystoid changes) during a four- to five-month double-masked, multicenter study in which patients were randomly assigned. A statistically significant improvement in distance visual acuity (two lines or more) was observed in the ketorolac-treated group as compared to the placebo-treated group after 30 days (P = .038), 60 days (P = .017), and 90 days (P = .008) of treatment. This improvement in visual acuity remained statistically significant one month after cessation of treatment (P = .001). Nine ketorolac-treated patients and two placebo-treated patients demonstrated a decrease in visual acuity one month after treatment was discontinued. Seven of the nine ketorolac-treated patients experienced an improvement in visual acuity after retreatment as compared to none of the placebo-treated patients. This study offers evidence for a more optimistic outlook in the medical treatment of chronic aphakic and pseudophakic cystoid macular edema.

A comparison of topical ketorolac, systemic flurbiprofen, and placebo for the inhibition of bone loss in adult periodontitis

Systemic non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce alveolar bone loss in periodontitis. This study assesses the efficacy of a topical NSAID rinse, containing ketorolac tromethamine as the active agent. Adult periodontitis patients (n = 55) were studied in this 6-month randomized, double blind, parallel, placebo and positive-controlled study. Each patient had a least 3 sites at high risk for bone loss as assessed by low dose bone scan. Groups, balanced for gender, were assigned to one of three regimens: bid ketorolac rinse (0.1%) with placebo capsule; 50 mg bid flurbiprofen capsule (positive control) with placebo rinse; or bid placebo rinse and capsule. Prophylaxes were provided every 3 months. Monthly examinations assessed safety, gingival condition, and gingival crevicular fluid PGE2. Standardized radiographs were taken at baseline and at 3 and 6 months for digital subtraction radiography. A significant loss in bone height was observed during the study period in the placebo group (-0.63 +/- 0.11; P < 0.001), but not in the flurbiprofen (-0.10 +/- 0.12; P = 0.40) or ketorolac rinse (+0.20 +/- 0.11 mm; P = 0.07) groups. Nested ANOVA revealed that ketorolac and flurbiprofen groups had less bone loss (P < 0.01) and reduced gingival crevicular fluid PGE2 levels (P < 0.03) compared to placebo. ANOVA suggests (P = 0.06) that ketorolac rinse preserved more alveolar bone than systemic flurbiprofen at the dose regimens utilized. These data indicate that ketorolac rinse may be beneficial in the treatment of adult periodontitis.

Synergistic antiallodynic effects of spinal morphine with ketorolac and selective COX1- and COX2-inhibitors in nerve-injured rats

The possible role of spinal prostanoids in the tactile allodynia and thermal hyperalgesia associated with an experimental model of neuropathic pain was investigated. Neuropathic pain was induced by tight ligation of the L5 and L6 spinal nerves. Tactile allodynia was assessed 7 days after the surgery by measuring hindpaw withdrawal threshold to probing with von Frey filaments. Thermal hyperalgesia and nociception were determined by the 52 degrees C warm-water tail-flick test and by applying radiant heat to the plantar aspect of the hindpaw ipsilateral to the ligation. Minimal antiallodynic effect was produced by intrathecal (i.th.) administration of ketorolac or morphine up to the highest testable dose (100 microg) or by the (R)- or (S)-enantiomers of ketorolac (up to 6 microg) when administered alone. However, i.th. administration of a fixed ratio (1:1) of morphine plus racemic ketorolac or of morphine plus the (S)-enantiomer of ketorolac (S-ketorolac) produced a dose- and time-related antiallodynic effect: ED50 114 +/- 35.9 microg (total dose) for morphine plus ketorolac and 70.5 +/- 21.0 microg (total dose) for morphine plus S-ketorolac. The combination of i.th. morphine plus the (R)-enantiomer of ketorolac (R-ketorolac) (up to 200 microg total dose) was without effect. Similar antiallodynic activity was obtained for the co-administration of i.th. morphine and intravenous (i.v.) racemic ketorolac. In order to investigate the role of cyclooxygenase (COX) isozymes, relatively selective COX1 (piroxicam) and COX2 N-[2-cyclohexyloxy-4-nitrophenyl] metanesulfonamide (NS-398) inhibitors were administered i.th. (60 microg) alone or together with i.th. morphine. Piroxicam, NS-398, morphine and vehicle (90% DMSO) were without significant antiallodynic effect when administered alone, but moderate antiallodynic effects were produced by i.th. administration of fixed ratio (1:1) combinations of morphine with 60 microg each (highest soluble dose) of piroxicam (%MPE = 40.8 +/- 10.2) or NS-398 (%MPE = 32.4 +/- 9.5). Further, the combined i.th. administration of morphine, piroxicam and NS-398 in fixed 1:1:1 ratio (60 microg each) resulted in a supraadditive antiallodynic effect (%MPE = 70.4 +/- 10.8). Finally, morphine, but not ketorolac, given i.th. produced dose-dependent anti nociception in either the tail-flick or the paw-flick tests. However, there was no synergy between morphine and ketorolac against thermal nociception in either of the tests. These findings suggest that spinal prostanoids produced via both COX1 and COX2 pathways may play a role in neuropathic pain states and suggest the clinical utility of opioid plus COX-inhibitor combination therapy.

Perioperative immunomodulation in cancer surgery

Despite undergoing a curative resection, many patients with colorectal cancer will develop and die of metastatic disease. It has been shown clinically and experimentally that surgery causes a transient period of immunosuppression, and it is postulated that this may encourage both the implantation of surgically disseminated tumor cells and the growth of existing micrometastases. The present study used natural killer cell cytotoxicity (NKCC) and tumor burden to evaluate perioperative modulation of immunocompetence in a murine model. We measured NKCC and tumor burden responses to a standardized surgical stress (SSS) alone, and to either morphine sulfate (MS) (15 mg/kg subcutaneously x 4 doses), ketorolac (a prostaglandin synthetase--prostaglandin E2--inhibitor) (2.5 mg/kg subcutaneously x 4 doses), or interleukin 2 (2,000 units intraperitoneally x 3 doses) administration with the SSS. In this model, we found that both low-dose interleukin-2 (IL-2) and ketorolac reversed the NKCC suppression associated with surgery, whereas morphine resulted in further depression of NKCC. In addition, IL-2 significantly decreased tumor incidence, whereas continuous MS exposure markedly increased tumor burden after surgery. These data suggest that IL-2 and ketorolac may be effective agents for the restoration of perioperative immune competence, whereas the use of continuous morphine might have significant deleterious effects.

Population pharmacodynamic model for ketorolac analgesia

OBJECTIVE

To derive a population pharmacokinetic-pharmacodynamic model that characterizes the distribution of pain relief scores and remedication times observed in patients receiving intramuscular ketorolac for the treatment of moderate to severe postoperative pain.

BACKGROUND

The data analysis approach deals with the complexities of analyzing analgesic trial data: (1) repeated measurements, (2) ordered categorical response variables, and (3) nonrandom censoring because the patients can take a rescue medication if their pain relief is insufficient.

METHODS

Patients (n = 522) received a single oral or intramuscular administration of placebo or a single intramuscular dose of 10, 30, 60, or 90 mg ketorolac for postoperative pain relief. Pain relief was measured periodically with use of a five-category ordinal scale up to 6 hours after dosing. In this period, 288 patients received additional medication because of insufficient pain relief. Pharmacokinetic data was available for 85 subjects. Models were fitted to the data with the NONMEM program.

RESULTS

The pharmacokinetic data was best described by a two-compartment model with first-order absorption. Pain relief was found to be a function of drug concentration (Emax model), time (waxing and waning of placebo effect), and an individual random effect. The drug concentration at half-maximal effect (EC50) and the first-order rate constant (keo) half-life for pain relief were 0.37 mg/L and 24 minutes. The probability of remedication was found to be a function of the observed level of pain relief and was found to increase with time. Monte Carlo simulations showed that adequate pain relief was achieved in 50% of the patients at 41, 27, 23, and 21 minutes after 10, 30, 60, or 90 mg of intramuscular ketorolac. Adequate pain relief was maintained up to 6 hours in 50%, 70%, 78%, and 81% of patients after these four doses. Only 25% of the patients achieved adequate pain relief with placebo.

CONCLUSIONS

A population pharmacokinetic-pharmacodynamic model for the analgesic efficacy of intramuscular ketorolac was derived. The simulated relationship between dose, time, and percentage of patients with adequate pain relief suggested that 30 mg intramuscular ketorolac was the optimal initial dose for postoperative pain relief.

Effectiveness of ketorolac tromethamine 0.5% ophthalmic solution for chronic aphakic and pseudophakic cystoid macular edema

The effect of ketorolac tromethamine 0.5% ophthalmic solution (a new nonsteroidal anti-inflammatory agent) treatment was compared to placebo treatment in patients with chronic, angiographically proven aphakic or pseudophakic cystoid macular edema (visual acuity less than or equal to 20/40 for six months) during a three- to four-month double-masked, randomized study. Twenty-six patients completed this study without significant ocular or systemic toxicity. The improved distance visual acuity observed in the ketorolac treatment group (8/13 patients) was statistically different from the improved vision observed in the placebo treated group (1/13 patients) (P = .005). No patient on a regimen of ketorolac therapy had a significant decrease in Snellen distance visual acuity while on treatment, but two patients in the placebo group demonstrated a decrease in visual acuity of two lines or more. Fluorescein angiography was consistent with changes in visual acuity.

Prophylaxis of aphakic cystoid macular edema without corticosteroids. A paired-comparison, placebo-controlled double-masked study

Prior investigations have reported that topical nonsteroidal anti-inflammatory drug (NSAID) therapy prevents the development of postoperative angiographic signs of angiographic cystoid macular edema (CME). However, these studies include concurrent use of corticosteroids. The current study reports therapeutic efficacy for ketorolac ophthalmic solution (an NSAID) in the prophylaxis of angiographic aphakic CME (ACME) after cataract surgery without concurrent corticosteroids for the first time. Fifty patients with bilateral cataracts were enrolled in this placebo-controlled, paired-comparison, double-masked study. Eleven patients had evidence of angiographic ACME on postoperative day 40. Two of these patients demonstrated bilateral ACME, one patient had ACME in the NSAID-treated eye, and eight patients demonstrated ACME in the placebo-treated eye. This is a statistically significant difference favoring drug treatment. The signs of anterior ocular inflammation were greater in the eyes with ACME. This study suggests prophylactic treatment of ACME may be possible without the risks of concurrent corticosteroid toxicity. In addition, a higher incidence of ACME in black patients (22%) is observed in this study than has been recognized previously.

Clinical study comparing acupuncture, physiotherapy, injection and oral anti-inflammatory therapy in shoulder-cuff lesions

In a single-blind trial, five treatments for painful stiff shoulder were compared for a 4-week assessment period in 60 patients. The treatments were acupuncture, steroid injection with placebo and with active tolmetin sodium, physiotherapy in the form of ultrasound and 'placebo' physiotherapy with placebo tolmetin sodium. Objective assessment was gained by use of goniometer readings to monitor shoulder abduction. Pain was measured by visual analogue scales and by a 4-point scale. Comparative assessment was also recorded and at the end of the study a success or failure was recorded for each patient's treatment. With very few exceptions all patients improved markedly, both in terms of the subjective and objective parameters. No differences between the treatments were detected. The incidence and severity of side-effects was low. It is suggested that the results show that the painful stiff shoulder may be a self-limiting condition and that any beneficial effect was really due to natural recovery. This is an important consideration because patients do not always receive immediate attention when referred to an out-patient department and the use of physiotherapy and acupuncture in such cases, perhaps, should be critically examined.

Ketorolac for postoperative pain management in children

Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) with potent analgesic effects and a relatively low incidence of adverse effects. Numerous clinical trials of postoperative pain treatment in children have shown that ketorolac is as effective as the major opioid analgesics, such as morphine, and more effective than codeine. The pharmacokinetics of ketorolac differ in children compared with adult patients after surgery. In children, the volume of distribution (Vd) of ketorolac is increased by as much as 2-fold relative to that in adults. The plasma clearance (CL) of ketorolac is also higher in children, probably because of lower binding to plasma proteins. However, the elimination half-life (t 1/2 beta) of ketorolac is similar in children and adults because t 1/2 beta is directly proportional to Vd but inversely proportional to CL. These pharmacokinetic differences indicate that a higher relative dosage is required in children, but the dosage interval is similar in children and adults. Ketorolac can be administered intravenously, intramuscularly or orally. The intravenous route is preferred during the immediate postoperative period, until the patient can tolerate oral medication. Intramuscular injections are not recommended in children, unless the intravenous route is unavailable. The recommended intravenous dosage of ketorolac in children is 0.5 mg/kg, followed either by bolus injections of 1.0 mg/kg every 6 hours or an intravenous infusion of 0.17 mg/kg/h. The maximum daily dosage is 90mg, and the maximum duration of treatment is 48 hours. The recommended oral dosage is 0.25 mg/kg to a maximum of 1.0 mg/kg/day, with a maximum duration of 7 days. Older children may require somewhat lower dosages, while infants and young children may require slightly higher dosages to achieve the same level of pain relief. Ketorolac is not recommended for use in infants aged < 1 year. Unlike opioid analgesics ketorolac does not depress ventilation, and is not associated with nausea and vomiting, urinary retention or sedation. When combined with an opioid, ketorolac exhibits marked opioid-sparing effects, allowing a lower dosage of opioid to be used. Clinical studies in children and adults show that the synergistic action of ketorolac and opioids improves the degree and quality of pain relief, and reduces the incidence of opioid-related adverse effects such as respiratory depression, nausea/vomiting and ileus. Recovery of bowel function after abdominal surgery occurs sooner in ketorolac-compared with opioid-treated patients. Ketorolac reversibly inhibits cyclo-oxygenase, and decreases the hypersensitisation of tissue nociceptors that occurs with surgery. It also has reversible antiplatelet effects, which are attributable to the inhibition of thromboxane synthesis. Bleeding time is usually slightly increased, but in most patients it remains within normal values. There is conflicting evidence of the potential for increased surgical-site bleeding after tonsillectomy but, for other types of paediatric surgery, numerous clinical studies have confirmed that ketorolac is not associated with increased bleeding. Thus, ketorolac is well suited for the treatment of postoperative pain in children, either alone or in combination with opioids or local anaesthetics, because of its analgesic potency and relatively low incidence of adverse effects.

Five studies on ibuprofen for postsurgical dental pain

Ibuprofen (Motrin, Upjohn) was evaluated in five studies using the Dental Pain Model, which is representative of most acute postsurgical pain situations. Ibuprofen 400 mg was consistently more effective than aspirin 650 mg, acetaminophen 600 mg, and both aspirin and acetaminophen when combined with codeine 60 mg. In two studies, ibuprofen 400 mg was at least as effective as zomepirac sodium 100 mg. No serious or prolonged side effects were reported in any of these studies.

Clinical pharmacokinetics of ketorolac tromethamine

Ketorolac is a new chiral nonsteroidal anti-inflammatory drug (NSAID) which is marketed for analgesia as the racemate. The drug is administered as the water soluble tromethamine salt and is available in tablets or as an intramuscular injection. The absorption of ketorolac is rapid, Cmax being attained between 20 to 60 min. Its oral bioavailability is estimated to range from 80 to 100%. The drug is extensively bound (> 99%) to plasma proteins and has a volume of distribution (0.1 to 0.3 L/kg) comparable with those of other NSAIDs. Only small concentrations of ketorolac are detectable in umbilical vein blood after administration to women in labour. The elimination half-life is between 4 and 6h and is moderate in comparison with other NSAIDs. The area under the plasma concentration-time curve of ketorolac is proportional to the dose after intramuscular administration of therapeutic doses to young healthy volunteers. Ketorolac is extensively metabolised through glucuronidation and oxidation; little if any drug is eliminated unchanged. Most of the dose of ketorolac is recovered in the urine as conjugated drug. Although ketorolac is excreted into the breast milk, the amount of drug transferred comprises only a small fraction of the maternal exposure. Little stereoselectivity was present in the pharmacokinetics of ketorolac in a healthy volunteer receiving single intravenous or oral doses. The elderly exhibit reduced clearance of the drug. Renal insufficiency appears to cause an accumulation of ketorolac in plasma, although hepatic disease may not affect the pharmacokinetics.

Comparison of i.m. ketorolac trometamol and morphine sulphate for pain relief after cholecystectomy

I.m. ketorolac trometamol 30 mg was compared with morphine sulphate 10 mg after cholecystectomy in a double-blind, multiple dose, randomized study of 100 patients. Assessments of pain were made immediately after operation (day 1), and the next morning (day 2). Pain intensity (verbal response score and visual analogue scale) was recorded before injection and then over a 6-h period. Pain relief was assessed also. The effect of ketorolac on operative blood loss and platelet function was examined. Time to commencing oral intake and the duration of administration of i.v. fluids were recorded. Adverse events were noted. Ketorolac produced significantly less analgesia than morphine on day 1, but on day 2 the two drugs produced a similar effect. Blood loss was not increased by ketorolac, although platelet function was impaired. Repeated i.m. administration of ketorolac did not produce any serious adverse effects.

Comparison of the analgesic and emetic properties of ketorolac and morphine for paediatric outpatient strabismus surgery

In a prospective, double-blind, randomized study, we have compared i.v. ketorolac and morphine in paediatric outpatients undergoing strabismus surgery. Forty-two ASA I or II children, aged 2-12 yr, were allocated randomly to receive either ketorolac 0.75 mg kg-1 i.v. or morphine 0.1 mg kg-1 i.v. and metoclopramide 0.15 mg kg-1. Anaesthesia was induced with propofol and maintained with propofol and nitrous oxide. Pain was assessed at 15-min intervals until discharge, and the incidence of nausea and vomiting was recorded for the first 24 h. There was no difference in pain behaviour scores or recovery times. The incidence of nausea and vomiting during the first 24 h was 19% in the ketorolac group and 71% in the morphine group (P < 0.001). We concluded that ketorolac was an effective analgesic for this type of surgery and that it was associated with less postoperative emesis than morphine and metoclopramide.

A review of upper-gastrointestinal effects of the newer nonsteroidal antiinflammatory agents

Newer nonsteroidal antiinflammatory agents (NSAI's) such as ibuprofen, neproxen, fenoprofen, and tolmetin have broadened the therapeutic choice and increased the chances of providing optimum arthritis control, but require careful assessment of the possibilities for unwanted drug effects when long-term therapy is required. A review of the literature on the gastrointestinal effects of the promising newer NSAIs, as compared with the older agents, aspirin, indomethacin, and phenylbutazone, is presented, highlighting animal toxicology and human adverse reaction surveillance data and the evidence for various suggested pathophysiological mechanisms.

Preoperative ketorolac increases bleeding after tonsillectomy in children

PURPOSE

To compare the incidence of vomiting following codeine or ketorolac for tonsillectomy in children.

METHODS

We had planned to enrol 240 patients, aged 2-12 yr undergoing elective tonsillectomy into a randomized, single-blind study in University Children's Hospital. The study was terminated, after 64 patients because interim analysis of the data by a blinded non-study scientist concluded that the patients were at undue risk of excessive perioperative bleeding. After induction of anaesthesia by inhalation with N2O/halothane or with propofol 2.5-3.5 mg.kg-1 i.v., the children were administered 150 micrograms.kg-1 ondansetron and 50 micrograms.kg-1 midazolam. Maintenance of anaesthesia was with N2O and halothane in O2. Subjects were administered either 1.5 mg.kg-1 codeine im or 1 mg.kg-1 ketorolac i.v. before the commencement of surgery. Intraoperative blood loss was measured with a Baxter Medi-Vac Universal Critical Measurement Unit. Postoperative management of vomiting and pain was standardized. Vomiting was recorded for 24 hr after anaesthesia. Data were compared with ANOVA, Chi-Square analysis and Fisher Exact Test.

RESULTS

Thirty-five subjects received ketorolac. Demographic data were similar. The incidence of vomiting during the postoperative period was 31% in the codeine-group and 40% in the ketorolac-group. Intraoperative blood losses was 1.3 +/- 0.8 ml.kg-1 after codeine and 2.2 +/- 1.9 ml.kg-1 after ketorolac (mean +/- SD) P < 0.05. Five ketorolac-treated patients had bleeding which led to unscheduled admission to hospital, P < 0.05, Exact Test.

CONCLUSION

Preoperative ketorolac increases perioperative bleeding among children undergoing tonsillectomy without beneficial effects.

The effect of intravenous ketorolac given intraoperatively versus postoperatively on outcome from gynecologic abdominal surgery

STUDY OBJECTIVES

To examine the effect of timing of an intravenous (i.v.) dose (intraoperative vs. postoperative) of ketorolac tromethamine on pain scores and overall outcome after total abdominal hysterectomy (TAH) and myomectomy.

DESIGN

Prospective, randomized, placebo-controlled study.

PATIENTS

248 ASA physical status I and II adult female patients scheduled for elective hysterectomy or myomectomy.

INTERVENTIONS

General anesthesia was administered that consisted of thiopental sodium for induction, enflurane or isoflurane in nitrous oxide-oxygen for maintenance, and small doses of fentanyl and midazolam. Patients were randomized into three groups to receive toradol/placebo on a dosing schedule of dose 1 given one-half hour prior to expected end of surgery, dose 2 given on awakening in the postanesthesia care unit, and doses 3, 4, and 5 given at 6, 12, and 18 hours, respectively, after dose 2; Group 1 patients received placebo (saline) for dose 1, ketorolac 60 mg i.v. for dose 2, and ketorolac 30 mg i.v. for doses 3, 4, and 5. Group 2 patients received ketorolac 60 mg i.v. for dose 1, placebo for dose 2, and ketorolac 30 mg i.v. for doses 3, 4, and 5. Group 3 patients received placebo for all doses. All patients were given i.v. morphine PCA postoperatively, and morphine usages, visual analog pain intensity (VAS) scores, as well as adverse events and median times to recovery milestones were recorded.

MEASUREMENTS AND MAIN RESULTS

VAS scores (mean) before dose 2 were significantly lower in Group 2 than Group 1, as were at-rest evaluations at 15 minutes and one hour. Group 2 patients also had decreased morphine requirements as compared to placebo. Both ketorolac groups (Groups 1 and 2) had significantly higher values for patient and observer overall ratings, case of nursing care, and tolerability as compared to placebo (Group 3). There were no significant differences among groups in adverse events or median times to recovery milestones.

CONCLUSIONS

Although it is possible to demonstrate an improvement in early postoperative pain scores with intraoperative ketorolac and better overall ratings of ketorolac both intraoperatively and postoperatively as compared with placebo, the lack of clinically significant differences in analgesic efficacy in the two active study groups indicates the need for a careful consideration by the clinician of the risks versus benefits involved in the administration of antiplatelet medication in the perioperative period.

Meperidine-related seizures associated with patient-controlled analgesia pumps

OBJECTIVE

To report three cases of meperidine-related seizures when meperidine was administered via patient-controlled analgesia pump (PCAP) and to review literature related to meperidine-associated seizures.

DATA SOURCES

Case reports and review articles identified by a computerized search (MEDLINE) and manual search (Index Medicus).

DATA SYNTHESIS

PCAPs are being used frequently to relieve the pain of sickle cell crisis as well as pain from many other etiologies. We report three cases of meperidine-related seizures associated with its administration via PCAP. Each of the patients received either relatively high doses, long-term therapy, or both. Meperidine has been associated with seizure activity when administered via traditional routes. Previously identified risk factors for the development of meperidine-related seizures include renal failure, high meperidine dosages, and coadministration of hepatic enzyme-inducing medications or phenothiazines.

CONCLUSIONS

Meperidine administered via PCAP may be associated with seizures. Optimally, an alternative analgesic should be administered when this route is used.

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.