Pharmacologic Properties of Ketorolac Tromethamine: A Potent Analgesic Drug

Melatonin protects against ketorolac induced gastric mucosal toxic injuries through molecular mechanism associated with the modulation of Arylakylamine N-Acetyltransferase (AANAT) activity

Ketorolac tromethamine (KT), is a widely used non-steroidal anti-inflammatory drug (NSAID) for treating moderate to severe pain. However, the use of KT has been restricted due to its highly toxic attributes that lead to severe gastric ulceration and bleeding. The protective effects of exogenous melatonin (MT) has been reported in conditions associated with gastro-intestinal disorders. This study aims at exploring the role of gastric endogenous MT level and it's metabolizing enzyme AANAT, at the onset of ketorolac mediated toxicities in the gastric mucosa. Gastric mucosal damage was induced in experimental rats by oral administration of graded doses of KT, where 50 mg/kg b.w. of KT was observed to incur maximum gastric lesions. However, gastric damages were found to be protected in rats, pre-treated with 60 mg/kg b.w. of MT. Post-sacrifice, mean ulcer index, oxidative status, total melatonin levels and enzyme activities associated with MT biosynthesis and catabolism were estimated. The results reveal that KT decreases AANAT activity with a concomitant decline in endogenous MT level which cumulatively aggravates gastric toxicity. Moreover, exogenous MT administration has been found to be protective in ameliorating this ulcerogenic process in rats, challenged with KT. Biochemical and histo-pathological observations revealed the reduction in oxidative stress level and replenishment of depleted gastric MT levels in MT pre-treated animals, which might be the causative factors in conferring protection to the gastric tissues and residing mitochondria. The results revealed a correlation between depleted gastric MT level and ulcer formation, which unveiled a novel ulcerogenic mechanism. This may bring forth future therapeutic relevance for treating patients suffering from KT mediated acute gastric toxicities.

Narrative review shows that the short-term use of ketorolac is safe and effective in the management of moderate-to-severe pain in children

In June 2013, the European Medicine Agency recommended limiting codeine use in paediatric patients, creating a void in managing moderate pain. We reviewed the literature published in English (1985-June 2017) on the pharmacokinetic, pharmacodynamic and safety profile of ketorolac, a possible substitute for codeine and opioids, for treating moderate-to-severe pain. We found that gastrointestinal side effects were mainly reported with prolonged use, significant bleeding was reported in adenotonsillectomy, and adverse renal effects appeared to be limited to patients with specific coexisting risk factors.

CONCLUSION

The short-term use of ketorolac appears to be safe for children in many situations.

The effect of ketorolac on pregnancy rates when used immediately after oocyte retrieval

OBJECTIVE

To study the effect of ketorolac, a potent anti-inflammatory medication, on in vitro fertilization (IVF) pregnancy outcomes when used at the time of oocyte retrieval.

DESIGN

Retrospective review of 454 patients from 2003-2009.

SETTING

Tertiary hospital-affiliated fertility center.

PATIENT(S)

Consecutive subfertile women undergoing their first IVF cycle.

INTERVENTION(S)

Ketorolac administration immediately after oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Pregnancy, implantation, live-birth, and miscarriage rates, and postsurgical visual analog pain score.

RESULT(S)

Of the 454 patients undergoing their first IVF cycle for all indications, 103 received intravenous ketorolac immediately after oocyte retrieval, based on anesthesiologist preference. Patient and procedural characteristics were similar between both groups. The use of ketorolac had no effect on the rates of implantation, miscarriage, pregnancy, live birth, or multiple pregnancy. The patients receiving ketorolac experienced statistically significantly less pain.

CONCLUSION(S)

This study suggests ketorolac has no apparent detrimental effect on IVF pregnancy outcomes when administered immediately after oocyte retrieval. Ketorolac appears to be a safe and effective analgesic to use at the time of oocyte retrieval.

Bioavailability of two sublingual formulations of ketorolac tromethamine 30 mg: a randomized, open-label, single-dose, two-period crossover comparison in healthy Mexican adult volunteers

BACKGROUND

Ketorolac tromethamine (ie, ketorolac) is an NSAID that appears to have several mechanisms of action, including inhibition of prostaglandin synthesis, modulatory effect on opioid receptors, and nitric oxide synthesis. Ketorolac is used in the treatment of pain. There are various generic formulations of sublingual ketorolac available in Mexico. However, a literature search did not identify published data concerning the bioavailability of these formulations in the Mexican population.

OBJECTIVE

The aim of this study was to compare the bioavailability of 2 sublingual formulations of ketorolac 30-mg tablets in healthy Mexican adult volunteers.

METHODS

This was a randomized-sequence, open-label, single-dose, 2-period crossover (2 dosing periods x 2 treatments) study comparing the bioavailability of two 30-mg sublingual tablet formulations of ketorolac. Healthy Mexican adult (aged, 18-55 years) men and women were eligible for inclusion. Subjects were randomly assigned in a 1:1 ratio to receive a single dose of the test formulation or the reference formulation. After a 12-hour overnight fast, subjects received a single dose of the corresponding formulation. There was a 7-day washout period between administration periods. Plasma samples were obtained over a 24-hour period after administration. Plasma ketorolac concentrations were analyzed by high-performance liquid chromatography for analysis of pharmacokinetic properties, including Cmax, AUC0-24, and AUC0-infinity. Blood samples were drawn immediately after sublingual placement of the drug and at 10, 20, 30, 40, 50, 60, 75, and 90 minutes and 2, 4, 6, 8, 10, 12, and 24 hours after dosing. The formulations were considered bioequivalent if the geometric mean ratios of Cmax and AUC were within the predetermined range of 80% to 125% and if P for the 90% CIs was <0.05. Tolerability was assessed by vital sign monitoring, laboratory analysis results, and subject interviews.

RESULTS

A total of 27 subjects (18 women, 9 men; mean [SD] age, 27 [9] years [range, 18-47 years]; weight, 61 [8] kg [48-79 kg]; height, 163 [8] cm [150-180 cm]) were enrolled and completed the study. Fourteen subjects received the test formulation first. No period or sequence effect was observed. The 90% CIs for the corresponding differences in natural log Cmax, AUC0-24, and AUC0-infinity were 95.94% to 114.66%, 98.34% to 105.90%, and 99.25% to 108.36%, respectively (all, (P) < 0.05), meeting the predetermined criteria for bioequivalence. Sixteen subjects experienced a total of 20 adverse events (AEs) during the study. None of the AEs were considered serious. One AE (nausea) appeared to be related to use of the reference formulation.

CONCLUSIONS

In this small study in 27 healthy Mexican adult volunteers, the test formulation of a single, 30-mg sublingual tablet of ketorolac appeared to be bioequivalent to the reference formulation based on the rate and extent of absorption. Both formulations were well tolerated.

Participation of the nitric oxide-cyclic GMP-ATP-sensitive K(+) channel pathway in the antinociceptive action of ketorolac

The involvement of nitric oxide (NO), cyclic GMP and ATP-sensitive K(+) channels in the antinociceptive effect of ketorolac was assessed using the formalin test in the rat. Local administration of ketorolac in a formalin-injured paw produced a dose-dependent antinociceptive effect due to a local action, as drug administration in the contralateral paw was ineffective. Pretreatment of the injured paw with N(G)-L-nitro-arginine methyl ester (L-NAME, an NO synthesis inhibitor), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, a soluble guanylyl cyclase inhibitor) or glibenclamide (an ATP-sensitive K(+) channel blocker) prevented ketorolac-induced antinociception. However, pretreatment with saline or N(G)-D-nitro-arginine methyl ester (D-NAME) did not block antinociception. Local administration of S-nitroso-N-acetylpenicillamine (SNAP, an NO donor) was inactive by itself, but increased the effect of ketorolac. The present results suggest that the antinociceptive effect of ketorolac involves activation of the NO-cyclic GMP pathway, followed by an opening of ATP-sensitive K(+) channels at the peripheral level.

Analgesic efficacy and bioavailability of ketorolac in postoperative pain: a probability analysis

BACKGROUND

The analgesic efficacy and bioavailability of 30 mg intramuscular ketorolac was studied in 24 patients with severe or very severe postoperative pain.

METHODS

Pain and pain relief were determined by a five-point verbal rating scale and data were submitted to a probability analysis. Ketorolac plasma levels were determined by high-performance liquid chromatography.

RESULTS

Two patients chose not to finish the study; 22 patients completed the study achieving at least good pain relief. Of these 22 patients, 13 reached complete pain relief. Ketorolac was rapidly absorbed. Notwithstanding, pain relief increased gradually, showing considerable delay with regard to plasma concentrations. Analysis of the probability-time curves revealed that 25% of the patients obtained moderate pain relief at 7 min after ketorolac administration, 50% at 11 min, 75% at 29 min, and 95% at 60 min. Good pain relief was achieved in 25, 50, and 75% of the patients at 1.1, 1.8, and 2.7 h, respectively. Complete pain relief was achieved in 25% and 50% of the patients at 2.6 h and 3.7 h, respectively. The probability of exhibiting an acceptable pain relief in responsive patients for more than 5 h was 0.97. No serious side effects were detected.

CONCLUSIONS

Results show that 30 mg intramuscular ketorolac is an adequate treatment for postoperative pain in the Mexican population. Therefore, the use of higher doses is not justified. Due to gradual installation of analgesia, administration of additional analgesic medication before 1 h is not recommended.