Ketorolac penetration into the cerebrospinal fluid of humans

Periarticular infiltration used in total joint replacements: an update and review article

Periarticular infiltration following total knee and hip arthroplasty has been demonstrated to be equivalent to peripheral nerve blocks for postoperative pain management. The ideal cocktail has not been established yet. We have conducted a literature search on PubMed and Embase. Our search criteria included randomized controlled trials (RCTs) and systematic reviews (SRs). We tried to only include the most recent studies to keep the information current. The included research focused at Dexmedetomidine, Liposomal Bupivacaine, Ropivacaine, Epinephrine, Ketorolac, Morphine, Ketamine and Glucocorticosteroids. Each medication's mode of action, duration, ideal dosage, contraindications, side effects and effectiveness have been summarized in the review article. This article will help the clinician to make an informed evidence-based decision about which medications to include in their ideal cocktail.

Nonsteroidal Anti-Inflammatory Drugs and Their Neuroprotective Role After an Acute Spinal Cord Injury: A Systematic Review of Animal Models

STUDY DESIGN

Systematic review.

OBJECTIVE

Spinal cord injuries (SCIs) resulting in motor deficits can be devastating injuries resulting in millions of health care dollars spent per incident. Nonsteroidal anti-inflammatory drugs (NSAIDs) are a potential class of drugs that could improve motor function after an SCI. This systematic review utilizes PRISMA guidelines to evaluate the effectiveness of NSAIDs for SCI.

METHODS

PubMed/MEDLINE, CINAHL, PsycINFO, Embase, and Scopus were reviewed linking the keywords of "ibuprofen," "meloxicam," "naproxen," "ketorolac," "indomethacin," "celecoxib," "ATB-346," "NSAID," and "nonsteroidal anti-inflammatory drug" with "spinal." Results were reviewed for relevance and included if they met inclusion criteria. The SYRCLE checklist was used to assess sources of bias.

RESULTS

A total of 2960 studies were identified in the PubMed/MEDLINE database using the above-mentioned search criteria. A total of 461 abstracts were reviewed in Scopus, 340 in CINAHL, 179 in PsycINFO, and 7632 in Embase. A total of 15 articles met the inclusion criteria.

CONCLUSIONS

NSAIDs' effectiveness after SCI is largely determined by its ability to inhibit Rho-A. NSAIDs are a promising therapeutic option in acute SCI patients because they appear to decrease cord edema and inflammation, increase axonal sprouting, and improve motor function with minimal side effects. Studies are limited by heterogeneity, small sample size, and the use of animal models, which might not replicate the therapeutic effects in humans. There are no published human studies evaluating the safety and efficacy of these drugs after a traumatic cord injury. There is a need for well-designed prospective studies evaluating ibuprofen or indomethacin after adult spinal cord injuries.

Investigation of sumatriptan and ketorolac trometamol in the human experimental model of headache

BACKGROUND

Pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) induces headache in healthy volunteers but the precise mechanisms by which PACAP38 leads to headache are unclear. We investigated the headache preventive effect of sumatriptan and ketorolac on PACAP38-induced headache in healthy volunteers. In addition, we explored contribution of vascular mechanisms to PACAP38-induced headache using high resolution magnetic resonance angiography.

METHODS

Thirty-four healthy volunteers were divided in two groups (A and B) and received infusion of PACAP38 (10 picomol/kg/min) over 20 min. Group A was pretreated with intravenous sumatriptan (4 mg) or ketorolac (30 mg) 20 min before infusion of PACAP38. Group B received infusion of sumatriptan or ketorolac as post-treatment 90 min after infusion of PACAP38. In both experiments, we used a randomized, double-blind, cross-over design. We recorded headache characteristics and circumference of extra-intracerebral arteries.

RESULTS

We found no difference in AUC _{(0-6 h)} of PACAP38-induced headache in group A, pretreated with sumatriptan or ketorolac (p = 0.297). There was no difference between sumatriptan and ketorolac in PACAP38-induced circumference change (AUC_{Baseline-110 min}) of MMA (p = 0.227), STA (p = 0.795) and MCA (p = 0.356). In group B, post-treatment with ketorolac reduced PACAP38-headache compared to sumatriptan (p < 0.001). Post-treatment with sumatriptan significantly reduced the circumference of STA (p = 0.039) and MMA (p = 0.015) but not of MCA (p = 0.981) compared to ketorolac. In an explorative analysis, we found that pre-treatment with sumatriptan reduced PACAP38-induced headache compared to no treatment (AUC_0-90min).

CONCLUSIONS

Post-treatment with ketorolac was more effective in attenuating PACAP38-induced headache compared to sumatriptan. Ketorolac exerted its effect without affecting PACAP38-induced arterial dilation, whereas sumatriptan post-treatment attenuated PACAP38-induced dilation of MMA and STA. Pre-treatment with sumatriptan attenuated PACAP38-induced headache without affecting PACAP38-induced arterial dilation. Our findings suggest that ketorolac and sumatriptan attenuated PACAP38-induced headache in healthy volunteers without vascular effects.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT03585894). Registered 13 July 2018.

Ketorolac tromethamine - routes and clinical implications

Opioids have long been used for analgesic purposes for a wide range of procedures. However, the binding of these drugs to opiate receptors has created various challenges to the clinician due to unfavorable side effect profiles and the potential for tolerance and abuse. In 1989, ketorolac became an approved nonsteroidal inflammatory drug (NSAID) for injectable use as an analgesic. Over the last 20 years, numerous studies have been conducted involving ketorolac. These studies have provided additional information about various routes of administration and their effect on the efficacy and the side effect profile of ketorolac. Moreover, ketorolac has been compared with several widely used analgesics. This review evaluates both the potential benefits and potential drawbacks of ketorolac generally, and specifically discusses routes of administration, including their advantages and disadvantages when compared to several traditional analgesics in both inpatient and outpatient settings.

Rocuronium-induced withdrawal movement: influence of ketorolac or a combination of lidocaine and ketorolac pretreatment

Background

Pain on injection of rocuronium is a common clinical problem. We compared the efficacy of lidocaine, ketorolac, and the 2 in combination as pretreatment for the prevention of rocuronium-induced withdrawal movement.

Methods

For this prospective, randomized, placebo-controlled, double-blind study a total of 140 patients were randomly allocated to one of 4 treatment groups to receive intravenously placebo (saline), lidocaine (20 mg), ketorolac (10 mg), or both (n = 35 for each group), with venous occlusion. The tourniquet was released after 2 min and anesthesia was performed using 5 mg/kg thiopental sodium followed by 0.6 mg/kg rocuronium. The withdrawal response was graded on a 4-point scale in a double-blind manner.

Results

The overall incidence of withdrawal movements after rocuronium was 34.3% with lidocaine (P = 0.001), 40% with ketorolac (P = 0.004), and 8.6% with both (P < 0.001), compared with 74.3% with placebo. There was a significantly lower incidence of withdrawal movements in patients receiving the lidocaine/ketorolac combination than in those receiving lidocaine or ketorolac alone (P = 0.009 and 0.002, respectively). The incidence of moderate to severe withdrawal movements was 14.3% with lidocaine, 17.2% with ketorolac, and 2.9% with lidocaine/ketorolac combination, as compared to 45.7% with the placebo. There was no significant difference in withdrawal movement between the lidocaine group and the ketorolac group.

Conclusions

Ketorolac pretreatment had an effect comparable to that of lidocaine in attenuating rocuronium-induced withdrawal movements and the lidocaine/ketorolac combination pretreatment, compared with lidocaine or ketorolac alone, effectively reduced withdrawal movements during rocuronium injection.

A randomized, controlled trial validates a peripheral supra-additive antihyperalgesic effect of a paracetamol-ketorolac combination

The combination of paracetamol with non-steroidal anti-inflammatory drugs (NSAIDs) is widely used; however, the nature and mechanism of their interaction are still debated. A double-blind, pharmacokinetic/pharmacodynamic, randomized, cross-over, placebo-controlled study was carried out in human healthy volunteers. The aim was to explore the existence of a positive interaction between paracetamol 1 g and ketorolac 20 mg administered intravenously on experimental pain models in human beings. The effects of the paracetamol-ketotolac combination were compared with similar doses of respective single analgesic and to placebo on the sunburn model (UVB-induced inflammation), cold pain tolerance and the nociceptive flexion reflex. The kinetics of the plasma concentrations of paracetamol and ketorolac were measured using 2D-liquid chromatography-mass spectrometry. Thirteen volunteers were screened, and 11 completed the study. Ketorolac significantly decreased primary hyperalgesia to heat stimuli compared with paracetamol (p < 0.014). The combination performed better than paracetamol (p < 0.001) and placebo (p < 0.042), increasing heat pain threshold by 1.5°C. The combination radically reduced primary hyperalgesia to mechanical stimulation (39%) compared with placebo (p < 0.002) and single agents (paracetamol p < 0.024 and ketorolac p < 0.032). The combination also reduced, slightly although significantly, the intensity of pain (10%) for the cold pressor test (versus placebo: p < 0.012, paracetamol: p < 0.019 and ketorolac p < 0.004). None of the treatments significantly affected the central models of pain at this dosage level. No pharmacokinetic interactions were observed. These results suggest a supra-additive pharmacodynamic interaction between paracetamol and ketorolac in an inflammatory pain model. The mechanism of this interaction could mainly rely on a peripheral contribution of paracetamol to the effect of NSAIDs.

Effects of intrathecal ketorolac on human experimental pain

BACKGROUND

Nonsteroidal antiinflammatory drugs, the most commonly used analgesics, reduce pain not only by inhibiting cyclooxygenase at peripheral sites of inflammation but also by potentially inhibiting cyclooxygenase in the central nervous system, especially the spinal cord. Animal studies suggest that products of cyclooxygenase in the spinal cord do not alter pain responses to acute noxious stimuli but reduce pain and sensitization after peripheral inflammation. We used a spinal injection of small doses of the cyclooxygenase inhibitor ketorolac to survey the role of spinal cyclooxygenase in human experimental pain and hypersensitivity states.

METHODS

After regulatory agency approval and informed consent, we examined the effect of 2.0 mg intrathecal ketorolac in 41 healthy volunteers to acute noxious thermal stimuli in normal skin and to mechanical stimuli in skin sensitized by topical capsaicin or ultraviolet burn. We also examined the effect of intravenous ketorolac.

RESULTS

Intrathecal ketorolac reduced hypersensitivity when it was induced by a combination of ultraviolet burn plus intermittent heat and, according to one of the two analytical strategies, when it was induced by ultraviolet burn alone.

CONCLUSIONS

These data suggest a more limited role for spinal cord cyclooxygenase in human pain states than predicted by studies in animals.

Update on the role of nonsteroidal anti-inflammatory drugs and coxibs in the management of acute pain

PURPOSE OF REVIEW

Although NSAIDs have been shown to reduce postoperative analgesics, their ability to reduce opioid-related adverse effects and improve functional outcomes is questioned. Further, perioperative NSAID use may contribute to cardiovascular toxicity and impaired bone healing. This review highlights recent advances in our understanding of the role perioperative NSAIDs have on modulating nociception, their benefits when utilized as components of a multimodal analgesic regimen, and potential deleterious cardiovascular and osteogenic effects.

RECENT FINDINGS

Recent research indicates that, in addition to peripheral blockade of prostaglandin synthesis, central inhibition of cyclooxygenase-2 may play an important role in modulating nociception. Although nonspecific NSAIDs provide analgesic efficacy similar to coxibs, their use has been limited in the perioperative setting because of platelet dysfunction and gastrointestinal toxicity. Coxibs may be a safer alternative in that setting. Both coxibs and traditional NSAIDs may contribute to a dose-dependent increase in cardiovascular toxicity and impaired osteogenesis. When used short term at the lowest effective dose, however, NSAIDs may provide for analgesic benefit without significant toxicity.

SUMMARY

When utilized as a component of a multimodal analgesic regimen for acute pain, short-term NSAID administration reduces opioid-related side effects and may contribute to improved functional outcomes without significant adverse effects.

How readily does ketorolac penetrate cerebrospinal fluid in children?

Ketorolac is a potent nonsteroidal anti-inflammatory analgesic used in postoperative pain management. Ketorolac elicits its analgesic action by inhibiting the cyclo-oxygenase enzyme in peripheral tissues and in the spinal cord. Central nervous system penetration of parenteral ketorolac has been evaluated in adults but not in children. In the present study we investigated ketorolac cerebrospinal fluid penetration via spinal anesthesia in 30 healthy children undergoing surgery in the lower part of the body. A single cerebrospinal fluid and blood sample was obtained between 11 minutes and 6 hours after receiving ketorolac 0.5 mg x kg(-1) IV. Ketorolac concentrations were determined by gas chromatography with mass spectrometric detection. Ketorolac was detected from 22 of the 30 cerebrospinal fluid samples, and the concentrations ranged between 0.2 and 7.6 microg x L(-1) (median, 0.6 microg x L(-1)). The cerebrospinal fluid to unbound plasma concentration-ratio ranged between 0.01 and 0.69 (median, 0.08). These low concentrations indicate that ketorolac does not readily penetrate cerebrospinal fluid in children.

Preoperative Cotreatment With Dextromethorphan and Ketorolac Provides an Enhancement of Pain Relief After Laparoscopic-assisted Vaginal Hysterectomy

OBJECTIVES

Both N-methyl-D-aspartate receptor antagonists and nonsteroidal anti-inflammatory drugs have been demonstrated to produce better postoperative pain relief. The concept of multimodal analgesia has also been used for clinical pain management. The aim of the present study was to examine the analgesic effect of preoperative cotreatment with dextromethorphan (DM) and ketorolac on postoperative pain management after laparoscopic-assisted vaginal hysterectomy (LAVH).

METHODS

Eighty ASA physical status I or II patients scheduled for LAVH were included and randomly assigned to 1 of 4 groups. Patients received intramuscular (IM) chorpheniramine 20 mg+ intravenous (IV) 2 mL of normal saline, IM DM 40 mg+IV 2 mL of normal saline, IM chorpheniramine 20 mg+IV 60 mg (2 mL) of ketorolac, and IM DM 40 mg+IV ketorolac 60 mg as the groups C, DM, Keto, and DM+Keto, respectively. All patients were given a patient-controlled analgesia (PCA) with morphine for pain relief postoperatively. Analgesic effects were evaluated using Visual Analog Scale pain scores at rest and during coughing, time to first PCA request for pain relief, total morphine consumption, bed rest time, and the time to first passage of flatus for 48 hours after surgery.

RESULTS

Patients in DM and Keto groups had significantly better pain relief than patients in group C. Patients in DM+Keto group exhibited the best postoperative pain relief among groups in the following several categories: time to first trigger of PCA, total morphine consumption, the worst Visual Analog Scale, bed rest time, and the time to first passage of flatus, demonstrating an enhanced effect between DM and ketorolac. Neither synergistic nor antagonistic interaction was observed between DM and ketorolac.

DISCUSSION

Preoperative treatment with both DM and ketorolac diminish postoperative pain. Our results suggest that the N-methyl-D-aspartate antagonist-DM and the nonsteroidal anti-inflammatory drugs-ketorolac cotreatment provide an enhancement of analgesia for postoperative pain management in patients after LAVH surgery.

The Effect of Intravenous Ketorolac on Capsaicin-Induced Deep Tissue Hyperalgesia

Preclinical and clinical studies have emphasized that persistent small afferent input will induce a state of central facilitation that can be attenuated by systemically administered nonsteroidal antiinflammatory drugs. However, these studies have been performed using cutaneous models of hyperalgesia. In this study we evaluated the effects of IV ketorolac on an experimental model of deep tissue hyperalgesia using IM capsaicin. We used a double-blind, placebo-controlled, crossover design. Ten subjects received 60 mg of ketorolac or placebo in 2 sessions separated by 1 wk. Capsaicin (100 microg in 10 microL) was then injected into the flexor carpi ulnaris muscle of the left forearm. After injection, spontaneous pain scores, pressure pain scores, gripping pain, pain distribution, and pain quality were recorded at 0, 5, 10, 15, 20, and 25 min. Cutaneous allodynia and dysesthesia were then mapped and thermal and mechanical thresholds were measured. The IM injection of capsaicin resulted in a reliable report of pain, hyperalgesia, and referred pain. Ketorolac had no effect on spontaneous pain, elicited pain, pain distribution, or secondary hyperalgesia induced by capsaicin. The findings of this study support the feasibility of further pharmacological studies using the IM capsaicin pain model.

Postoperative Modulation of Central Nervous System Prostaglandin E2by Cyclooxygenase Inhibitors after Vascular Surgery: Retracted

BACKGROUND

The clinical availability of injectable cyclooxygenase inhibitors allows examination of the importance of cyclooxygenase 1 and 2 after surgery. The authors hypothesize that spinal prostaglandin E2 increases with lower extremity vascular surgery and that spinal prostaglandin E2 decreases with intravenous postsurgical administration of either a mixed cyclooxygenase 1/2 inhibitor (ketorolac) or a cyclooxygenase 2 selective inhibitor (parecoxib).

METHODS

Thirty patients undergoing elective lower extremity revascularization under continuous spinal anesthesia had cerebrospinal fluid obtained at baseline and then up to 6 h after the start of surgery. Four hours after surgical incision, patients were randomized to receive intravenous parecoxib 40 mg, ketorolac 30 mg, or preservative-free normal saline. Patients were administered intravenous fentanyl in the postanesthesia care unit and acetaminophen/oxycodone on the surgical ward to control pain.

RESULTS

Cerebrospinal fluid prostaglandin E2 concentrations were increased during and after surgery. After surgery, intravenous parecoxib 40 mg rapidly decreased cerebrospinal fluid prostaglandin E2, and intravenous ketorolac 30 mg also reduced cerebrospinal fluid prostaglandin E2 compared with placebo, but not as much as parecoxib. Postanesthesia care unit pain scores were reduced in the two drug groups compared with placebo, and surgical ward pain scores were also decreased for both drug groups, especially with parecoxib. No patient receiving parecoxib required postoperative intravenous fentanyl. Acetaminophen/oxycodone consumption was reduced in both drug groups compared with placebo, more so with parecoxib.

CONCLUSIONS

Cerebrospinal fluid prostaglandin E2 is elevated in patients after lower extremity vascular surgery. Postsurgical intravenous administration of the cyclooxygenase 1/2 inhibitor ketorolac, and especially the cyclooxygenase 2 inhibitor parecoxib, reduces cerebrospinal fluid prostaglandin E2 concentration and postoperative pain.

What is the role of NSAIDs in pre-emptive analgesia?

NSAIDs inhibit the cyclo-oxygenase enzymes, and decrease peripheral and central prostaglandin production. In addition to reducing the inflammation that accompanies tissue injury, decreasing prostaglandin production attenuates the response of the peripheral and central components of the nervous system to noxious stimuli. Such a reduction in the response to pain can reduce the peripheral and central sensitisation induced by noxious stimuli, and reduce the pain experienced in response to subsequent noxious stimuli. These properties would seem to make NSAIDs ideal drugs to use in a pre-emptive fashion, where analgesics are administered prior to a noxious stimulus, such as surgery, with the expectation that reduction in peripheral and central sensitisation will lead to a decrease of pain.However, the available perioperative trials of pre-emptive NSAID use have yielded modest or equivocal results, and these may be due, in part, to controversy associated with the definition of pre-emptive analgesia and how to conduct the corresponding clinical trials. Although NSAIDs may have a limited ability by themselves to induce a pre-emptive analgesic effect, the available trials suggest how the perioperative use of these drugs may be made more effective. It is expected that NSAIDs will play an increasing role in multimodal analgesia and pain relief in general.

Phase I safety assessment of intrathecal ketorolac

Spinal prostaglandin synthesis has been implicated in acute pain processes and in generation and maintenance of central sensitization, and intrathecal injection of cyclo-oxygenase (COX) inhibitors produce antinociception and reduce hypersensitivity in animals. We herein report a Phase I safety assessment of intrathecal injection of the COX inhibitor, ketorolac, in healthy volunteers, and demonstrate no serious side effects. Preclinical studies suggest a major site of action of COX inhibitors for analgesia lies in the central nervous system, especially the spinal cord. For example, COX isoenzymes are expressed in the spinal cord, acute noxious stimuli and inflammation increase spinal prostaglandin production, and spinally administered prostaglandins excite dorsal horn projection neurons, induce release of excitatory neurotransmitters, and cause nociceptive behavior. Intrathecal injection of COX inhibitors increases thermal and mechanical withdrawal threshold in animals with inflammation or nerve injury at doses several 100-fold less than those required systemically. Following pre-clinical neurotoxicity screening and regulatory agency approval, we examined the safety of intrathecal injection of a preservative-free formulation of the COX inhibitor, ketorolac. In an open label, dose-escalating design, 20 healthy volunteers received intrathecal ketorolac, 0.25, 0.5, 1, or 2mg (n=5 per group). Ketorolac did not alter blood pressure, although there was small (10-12%), dose-independent reduction in heart rate for the first hour after injection when data from all subjects were pooled. Ketorolac did not affect sensory or motor function or deep tendon reflexes, and there were no subjective sensations, neurologic or otherwise, reported by the volunteers. Ketorolac did not reduce pain report to heat stimuli applied to the lateral calf. One subject had a mild headache 24h after study, resolving the next day. There were no long-term side effects 6 months after study. These data suggest that intrathecal ketorolac does not produce a high incidence of serious adverse events, and they support further investigation for analgesia.

The clinical, cerebrospinal fluid, and histopathologic effects of epidural ketorolac in dogs

OBJECTIVE

To evaluate the clinical, cerebrospinal fluid (CSF), and histopathologic effects of epidural ketorolac.

STUDY DESIGN

Blinded, randomized, placebo controlled study.

ANIMALS

Twenty-two adult mixed breed dogs with 16 treatment and 6 control dogs, weighing 14.4 to 29.8 kg.

METHODS

Dogs were anesthetized and epidural catheters were placed at the lumbosacral space. Catheter placement was evaluated fluoroscopically. Ketorolac (0.4 mg/kg) or placebo (5% ethanol) was administered epidurally over a 52-hour period, with 5 injections given at 12-hour intervals. At 1, 2, 4, or 8 hours after the first and last injection of ketorolac, dogs were anesthetized and CSF was obtained. Control dogs had CSF sampled 1 hour after the first and last ethanol injection. Neurologic function and pain responses were evaluated before and during the study. Selected dogs were then killed and necropsies performed.

RESULTS

None of the dogs exhibited any clinical or neurologic abnormalities during the study. No statistical difference was noted in pain response or CSF analysis between treatment and control dogs. Gross necropsy revealed gastrointestinal ulceration of varying degrees in all treatment dogs. Histopathologic analysis of the spinal cord and meninges revealed minimal focal leptomeningeal phlebitis in 2 of 8 treatment dogs and minor subdural inflammation in 1 control dog. No changes to the neural structures were noted in any dogs.

CONCLUSIONS

Epidural administration of ketorolac did not cause clinical signs, alteration in CSF values, or pathologic changes to the spinal cord when used for short duration. Gastrointestinal ulceration was common when ketorolac was administered epidurally at 0.4 mg/kg every 12 hours for 5 treatments.

CLINICAL RELEVANCE

This study documented the neurologic safety of epidural ketorolac in dogs before an efficacy trial can be performed. Gastrointestinal ulceration may limit use to short duration or a single injection.

Mechanisms of actions of opioids and non-steroidal anti-inflammatory drugs

Opioids and non-steroidal anti-inflammatory drugs (NSAIDs) are the commonest drugs used to treat pain. Opioids mimic the actions of endogenous opioid peptides by interacting with mu, delta or kappa opioid receptors. The opioid receptors are coupled to G1 proteins and the actions of the opioids are mainly inhibitory. They close N-type voltage-operated calcium channels and open calcium-dependent inwardly-rectifying potassium channels. This results in hyperpolarization and a reduction in neuronal excitability. They also decrease intracellular cAMP which modulates the release of nociceptive neurotransmitters (e.g. substance P). Inhibition of prostaglandin synthesis by cyclooxygenase is the principal mode of the analgesic and anti-inflammatory actions of NSAIDs. Cyclo-oxygenase is inhibited irreversibly by aspirin and reversibly by other NSAIDs. The widespread inhibition of cyclo-oxygenase is responsible for many of the adverse effects of these drugs. NSAIDs also reduce prostaglandin production within the CNS. This is the main action of paracetamol.

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.

Preclinical and clinical development of dexketoprofen

Dexketoprofen trometamol is a water-soluble salt of the dextrorotatory enantiomer of the nonsteroidal anti-inflammatory drug (NSAID) ketoprofen. Racemic ketoprofen is used as an analgesic and an anti-inflammatory agent, and is one of the most potent in vitro inhibitors of prostaglandin synthesis. This effect is due to the S(+)-enantiomer (dexketoprofen), while the R(-)-enantiomer is devoid of such activity. The pharmacokinetic profile of ketoprofen and its enantiomers was assessed in several animals species and in human volunteers. In humans, the relative bioavailability of oral dexketoprofen trometamol (12.5 and 25 mg, respectively) is similar to that of oral racemic ketoprofen (25 and 50 mg, respectively), as measured in all cases by the area under the concentration-time curve values for S(+)-ketoprofen. Dexketoprofen trometamol, given as a tablet, is rapidly absorbed, with a time to maximum plasma concentration (tmax) of between 0.25 and 0.75 hours, whereas the tmax for the S-enantiomer after the racemic drug, administered as tablets or capsules prepared with the free acid, is between 0.5 and 3 hours. Peak plasma concentrations of 1.4 and 3.1 mg/L are reached after administration of dexketoprofen trometamol 12.5 and 25 mg, respectively. From 70 to 80% of the administered dose is recovered in the urine during the first 12 hours, mainly as the acyl-glucuronoconjugated parent drug. No R(-)-ketoprofen is found in the urine after administration of dexketoprofen [S(+)-ketoprofen], confirming the absence of bioinversion of the S(+)-enantiomer in humans. in animal studies, the anti-inflammatory potency of dexketoprofen was always equivalent to that demonstrated by twice the dose of ketoprofen. Similarly, animal studies showed a high analgesic potency for dexketoprofen trometamol. The R(-)-enantiomer demonstrated a much lower potency, its analgesic action being apparent only in conditions where the metabolic bioinversion to the S(+)-enantiomer was significant. The gastric ulcerogenic effect of dexketoprofen at various oral doses (1.5 to 6 mg/kg) in the rat do not differ from those of the corresponding double doses (3 to 12 mg/kg) of racemic ketoprofen. Repeated (5-day) oral administration of dexketoprofen as the trometamol salt causes less gastric ulceration than was observed after the acid form of both dexketoprofen and the racemate. In addition, single dose dexketoprofen as the free acid at 10 to 20 mg/kg does not show a significant intestinal ulcerogenic effect in rats, while racemic ketoprofen 20 or 40 mg/kg is clearly ulcerogenic to the small intestine. The analgesic efficacy of oral dexketoprofen trometamol 10 to 20 mg is superior to that of placebo and similar to that of ibuprofen 400 mg in patients with moderate to serve pain after third molar extraction. The time to onset of pain relief appeared to be shorter in patients treated with dexketoprofen trometamol than in those treated with ibuprofen 400 mg. Dexketoprofen trometamol was well tolerated, with a reported incidence of adverse events similar to that of placebo.

Non-steroidal anti-inflammatory drugs and spinal nociceptive processing

Non-steroidal anti-inflammatory drugs have a direct action on spinal nociceptive processing in vivo with a relative order of potency which correlates with their capacity as inhibitors of cyclooxygenase activity. However, recent clinical surveys and new in vivo evidence strongly suggest that for some of these agents, centrally mediated analgesia may also be achieved by additional mechanisms, which are independent of prostaglandin synthesis inhibition. In this review we explore the likelihood for such mechanisms following an extensive survey of existing data. The implications of these mechanisms are discussed in the light of our current understanding of spinal nociceptive processing.