Ketorolac Tromethamine is a member of the pyrrolo-pyrrole group of nonsteroidal anti-inflammatory drugs (NSAIDs). The chemical name for Ketorolac Tromethamine is (±)-5-benzoyl-2, 3-dihydro-1H-pyrrolizine-1-carboxylic acid, compound with 2-amino-2-(hydroxymethyl)-1,3-propanediol, and the structural formula is:
Ketorolac Tromethamine is a racemic mixture of [-]S and [+]R Ketorolac Tromethamine. Ketorolac Tromethamine may exist in three crystal forms. All forms are equally soluble in water. Ketorolac Tromethamine has a pKa of 3.5 and an n-octanol/water partition coefficient of 0.26. The molecular weight of Ketorolac Tromethamine is 376.41 and the molecular formula is C19H24N2O6.
Ketorolac Tromethamine is available for intravenous (IV) or intramuscular (IM) administration as: 15 mg in 1 mL (1.5%), 30 mg in 1 mL (3%) in sterile solutions; 60 mg in 2 mL (3%) of Ketorolac Tromethamine in sterile solution is available for IM administration only. The solutions contain 10% (w/v) alcohol, and 6.68 mg, 4.35 mg, and 8.70 mg, respectively, of sodium chloride in sterile water. The pH is adjusted with sodium hydroxide and/or hydrochloric acid, and the solutions are packaged with nitrogen. The sterile solutions are clear and slightly yellow in color.
Ketorolac Tromethamine - Clinical Pharmacology
PHARMACODYNAMICS
Ketorolac Tromethamine is a nonsteroidal anti-inflammatory drug (NSAID) that exhibits analgesic activity in animal models. Ketorolac Tromethamine inhibits synthesis of prostaglandins and may be considered a peripherally-acting analgesic. The biological activity of Ketorolac Tromethamine is associated with the S-form. Ketorolac Tromethamine possesses no sedative or anxiolytic properties.
The peak analgesic effect of Ketorolac Tromethamine occurs within 2 to 3 hours and is not statistically significantly different over the recommended dosage range of Ketorolac Tromethamine. The greatest difference between large and small doses of Ketorolac Tromethamine by either route is in the duration of analgesia.
PHARMACOKINETICS
Ketorolac Tromethamine is a racemic mixture of [-]S- and [+]R-enantiomeric forms, with the S-form having analgesic activity.
Comparison of IV, IM and Oral Pharmacokinetics
The pharmacokinetics of Ketorolac Tromethamine, following IV, IM and oral doses of Ketorolac Tromethamine, are compared in Table 1. In adults, the extent of bioavailability following administration of the oral and IM forms of Ketorolac Tromethamine was equal to that following an IV bolus.
Linear Kinetics
In adults, following administration of single oral, IM or IV doses of Ketorolac Tromethamine, in the recommended dosage ranges, the clearance of the racemate does not change. This implies that the pharmacokinetics of Ketorolac Tromethamine in adults, following single or multiple IM, IV, or recommended oral doses of Ketorolac Tromethamine, are linear. At the higher recommended doses, there is a proportional increase in the concentrations of free and bound racemate.
Distribution
The mean apparent volume (Vβ) of Ketorolac Tromethamine following complete distribution was approximately 13 liters. This parameter was determined from single-dose data.
The Ketorolac Tromethamine racemate has been shown to be highly protein-bound (99%). Nevertheless, even plasma concentrations as high as 10 mcg/mL will only occupy approximately 5% of the albumin binding sites. Thus, the unbound fraction for each enantiomer will be constant over the therapeutic range. A decrease in serum albumin, however, will result in increased free drug concentrations.
Ketorolac Tromethamine is excreted in human milk (see PRECAUTIONS: Lactation and Nursing).
Metabolism
Ketorolac Tromethamine is largely metabolized in the liver. The metabolic products are hydroxylated and conjugated forms of the parent drug. The products of metabolism, and some unchanged drug, are excreted in the urine.
Excretion
The principal route of elimination of ketorolac and its metabolites is renal. About 92% of a given dose is found in the urine, approximately 40% as Metabolites and 60% as unchanged ketorolac. Approximately 6% of a dose is excreted in the feces.
A single-dose study with 10 mg Ketorolac Tromethamine (n=9) demonstrated that the S-enantiomer is cleared approximately two times faster than the R-enantiomer, and that the clearance was independent of the route of administration. This means that the ratio of S/R plasma concentrations decreases with time after each dose. There is little or no inversion of the R- to S- form in humans. The clearance of the racemate in normal subjects, elderly individuals, and in hepatically and renally impaired patients, is outlined in Table 2.
The half-life of the Ketorolac Tromethamine S-enantiomer was approximately 2.5 hours (SD±0.4) compared with 5 hours (SD±1.7) for the R-enantiomer. In other studies, the half-life for the racemate has been reported to lie within the range of 5 to 6 hours.
Table 1
Table of Approximate Average Pharmacokinetic Parameters (Mean±SD)
Following Oral, Intramuscular and Intravenous Doses of Ketorolac Tromethamine
|
|
Oral†
|
Intramuscular*
|
Intravenous Bolus‡
|
Pharmacokinetic
Parameters (units)
|
10 mg
|
15 mg
|
30 mg
|
60 mg
|
15 mg
|
30 mg
|
|
|
|
|
|
|
|
Bioavailability (extent)
|
100%
|
Tmax1 (min)
|
44±34
|
33±21**
|
44±29
|
33±21**
|
1.1±0.7**
|
2.9±1.8
|
Cmax2 (mcg/mL) [Single-dose]
|
0.87±0.22
|
1.14±0.32**
|
2.42±0.68
|
4.55±1.27**
|
2.47±0.51**
|
4.65±0.96
|
Cmax (mcg/mL) [steady state qid]
|
1.05±0.26**
|
1.56±0.44**
|
3.11±0.87**
|
N/A††
|
3.09±1.17**
|
6.85±2.61
|
Cmin3 (mcg/mL) [steady state qid]
|
0.29±0.07**
|
0.47±0.13**
|
0.93±0.26**
|
N/A
|
0.61±0.21**
|
1.04±0.35
|
Cavg4 (mcg/mL) [steady state qid]
|
0.59±0.2**
|
0.94±0.29**
|
1.88±0.59**
|
N/A
|
1.09±0.3**
|
2.17±0.59
|
Vβ5 (L/kg)
|
—————— 0.175±0.039———————
|
0.210±0.044
|
% Dose metabolized = <50
% Dose excreted in urine = 91
|
% Dose excreted in feces = 6
% Plasma protein binding = 99
|
1Time-to-peak plasma concentration
2Peak plasma concentration
3Trough plasma concentration
4Average plasma concentration
5Volume of distribution
|
†Derived from PO pharmacokinetic studies in 77 normal fasted volunteers
*Derived from IM pharmacokinetic studies in 54 normal volunteers
‡Derived from IV pharmacokinetic studies in 24 normal volunteers
††Not applicable because 60 mg is only recommended as a single dose
**Mean value was simulated from observed plasma concentration data and standard deviation was simulated from percent coefficient of variation for observed Cmax and Tmax data
|
Table 2
The Influence of Age, Liver and Kidney Function, on the Clearance and
Terminal Half-life of Ketorolac Tromethamine (IM 1 and ORAL 2) in Adult Populations
|
|
Total Clearance [in L/h/kg]3
|
Terminal Half-life [in hours]
|
Type of Subjects
|
IM
Mean (range)
|
ORAL
Mean (range)
|
IM
Mean (range)
|
ORAL
Mean (range)
|
Normal Subjects
IM (n=54)
mean age=32, range=18-60
Oral (n=77)
mean age=32, range=20-60
|
0.023
(0.010-0.046)
|
0.025
(0.013-0.050)
|
5.3
(3.5-9.2)
|
5.3
(2.4-9)
|
Healthy Elderly Subjects
IM (n=13), Oral (n=12)
mean age=72, range=65-78
|
0.019
(0.013-0.034)
|
0.024
(0.018-0.034)
|
7
(4.7-8.6)
|
6.1
(4.3-7.6)
|
Patients with Hepatic Dysfunction
IM and Oral (n=7)
mean age=51, range=43-64
|
0.029
(0.013-0.066)
|
0.033
(0.019-0.051)
|
5.4
(2.2-6.9)
|
4.5
(1.6-7.6)
|
Patients with Renal Impairment
IM (n=25), Oral (n=9)
serum creatinine=1.9-5.0 mg/dL,
mean age (IM)=54, range=35-71
mean age (Oral)=57, range=39-70
|
0.015
(0.005-0.043)
|
0.016
(0.007-0.052)
|
10.3
(5.9-19.2)
|
10.8
(3.4-18.9)
|
Renal Dialysis Patients
IM and Oral (n=9)
mean age=40, range=27-63
|
0.016
(0.003-0.036)
|
−
|
13.6
(8-39.1)
|
−
|
1Estimated from 30 mg single IM doses of Ketorolac Tromethamine
2Estimated from 10 mg single oral doses of Ketorolac Tromethamine
3Liters/hour/kilogram
|
IV-Administration: In normal subjects (n=37), the total clearance of 30 mg IV-administered Ketorolac Tromethamine was 0.030 (0.017-0.051) L/h/kg. The terminal half-life was 5.6 (4-7.9) hours.
|
Accumulation
Ketorolac Tromethamine administered as an IV bolus every 6 hours for 5 days to healthy subjects (n=13), showed no significant difference in Cmax on Day 1 and Day 5. Trough levels averaged 0.29 mcg/mL (SD±0.13) on Day 1 and 0.55 mcg/mL (SD±0.23) on Day 6. Steady state was approached after the fourth dose.
Accumulation of Ketorolac Tromethamine has not been studied in special populations (geriatric, pediatric, renal failure or hepatic disease patients).
Kinetics in Special Populations
Geriatric Patients
Based on single-dose data only, the half-life of the Ketorolac Tromethamine racemate increased from 5 to 7 hours in the elderly (65 to 78 years) compared with young healthy volunteers (24 to 35 years) (see Table 2). There was little difference in the Cmax for the two groups (elderly, 2.52 mcg/mL±0.77; young, 2.99 mcg/mL±1.03) (see PRECAUTIONS − Geriatric Use).
Pediatric Patients
Following a single intravenous bolus dose of 0.5 mg/kg in 10 children 4 to 8 years old, the half-life was 6 hours (range: 3.5 to 10 h), the average clearance was 0.042 L/hr/kg and the Vd was 0.26 L/kg (range: 0.19 to 0.44 L/kg). In a second study, following a single intravenous dose of 0.6 mg/kg in 24 children 3 to 18 years old, Cmax was 4.3 ± 1.7 mcg/mL, Tmax was 10.25 ± 1.15 minutes, half-life was 3.8 ± 2.6 hours, Cl was 0.0678 L/hr/kg and Vd was 0.25 L/kg. The volume of distribution and clearance of ketorolac in pediatric patients was twice that observed in adult subjects (see Tables 1 and 2). There are no pharmacokinetic data available for Ketorolac Tromethamine administration by the IM route in pediatric patients.
Renal Insufficiency
Based on single-dose data only, the mean half-life of Ketorolac Tromethamine in renally impaired patients is between 6 and 19 hours and is dependent on the extent of the impairment. There is poor correlation between creatinine clearance and total Ketorolac Tromethamine clearance in the elderly and populations with renal impairment (r=0.5).
In patients with renal disease, the AUC∞ of each enantiomer increased by approximately 100% compared with healthy volunteers. The volume of distribution doubles for the S-enantiomer and increases by 1/5th for the R-enantiomer. The increase in volume of distribution of Ketorolac Tromethamine implies an increase in unbound fraction.
The AUC∞ ratio of the Ketorolac Tromethamine enantiomers in healthy subjects and patients remained similar, indicating there was no selective excretion of either enantiomer in patients compared to healthy subjects (see WARNINGS – Renal Effects and Table 2).
Hepatic Insufficiency
There was no significant difference in estimates of half-life, AUC∞ and Cmax in 7 patients with liver disease compared to healthy volunteers (see PRECAUTIONS – Hepatic Effects and Table 2).
Race
Pharmacokinetic differences due to race have not been identified.
Clinical Studies
Adult Patients
The analgesic efficacy of intramuscularly and intravenously administered Ketorolac Tromethamine was investigated in two postoperative pain models: general surgery (orthopedic, gynecologic and abdominal) and oral surgery (removal of impacted third molars). The studies were double-blind, single- and multiple-dose, parallel trial designs in patients with moderate to severe pain at baseline. Ketorolac Tromethamine injection was compared as follows: IM to meperidine or morphine administered intramuscularly, and IV to morphine administered either directly IV or through a PCA (Patient-Controlled Analgesia) pump.
Short-term Use (up to 5 days) Studies
In adults, the comparisons of intramuscular administration during the first hour, the onset of analgesic action was similar for Ketorolac Tromethamine and the narcotics, but the duration of analgesia was longer with Ketorolac Tromethamine than with the opioid comparators meperidine or morphine.
In a multi-dose, postoperative (general surgery) double-blind trial of Ketorolac Tromethamine 30 mg IM versus morphine 6 and 12 mg IM, each drug given on an “as needed” basis for up to 5 days, the overall analgesic effect of Ketorolac Tromethamine 30 mg IM was between that of morphine 6 and 12 mg. The majority of patients treated with either Ketorolac Tromethamine or morphine were dosed for up to 3 days; a small percentage of patients received 5 days of dosing.
In clinical settings where perioperative morphine was allowed, Ketorolac Tromethamine 30 mg IV, given once or twice as needed, provided analgesia comparable to morphine 4 mg IV once or twice as needed.
There was relatively limited experience with 5 consecutive days of IV-administered Ketorolac Tromethamine in controlled clinical trials, as most patients were given the drug for 3 days or less. The adverse events seen with IV-administered Ketorolac Tromethamine were similar to those observed with IM-administered Ketorolac Tromethamine, as would be expected based on the similar pharmacokinetics and bioequivalence (AUC, clearance, plasma half-life) of IV and IM routes of Ketorolac Tromethamine administration.
Pediatric Patients
The analgesic efficacy of single doses of Ketorolac Tromethamine has been demonstrated by showing a decrease in the need for supplemental narcotic in pediatric patients receiving ketorolac as compared to placebo. See discussion of these results under Clinical Studies with Concomitant Use of Opioids below.
Clinical Studies with Concomitant Use of Opioids
Adult Patients
Clinical studies in postoperative pain management have demonstrated that Ketorolac Tromethamine injection, when used in combination with opioids, significantly reduced opioid consumption. This combination may be useful in the subpopulation of patients especially prone to opioid-related complications. Ketorolac Tromethamine and narcotics should not be administered in the same syringe.
In a postoperative study, where all patients received morphine by a PCA device, patients treated with Ketorolac Tromethamine intravenously as fixed intermittent boluses (e.g., 30 mg initial dose followed by 15 mg q3h), required significantly less morphine (26%) than the placebo group. Analgesia was significantly superior, at various postdosing pain assessment times, in the patients receiving Ketorolac Tromethamine intravenously plus PCA morphine as compared to patients receiving PCA-administered morphine alone.
Pediatric Patients: Ketorolac Tromethamine injection reduced the need for supplemental opioid (fentanyl), when a 1 mg/kg dose was administered immediately following tonsillectomy compared to saline controls (see WARNINGS: Hemorrhage). In another study, when a single bolus dose of 0.9 mg/kg of Ketorolac Tromethamine injection was given to pediatric patients ages 5 to 12 years, compared to saline, a reduction in supplemental opioid was needed following various surgical procedures. In a third study less supplemental morphine was needed in pediatric patients ages 8 to 16 years, who received a 0.8 mg/kg IV injection of Ketorolac Tromethamine injection in conjunction with morphine following orthopedic surgical procedures, compared to morphine alone. In a study in pediatric patients ages 3 to 12 years, Ketorolac Tromethamine injection demonstrated a slower onset of analgesia, but a longer duration of action compared to morphine. There is limited data available to support the use of multiple doses of Ketorolac Tromethamine injection in pediatric patients. There are also insufficient data available to support the use of Ketorolac Tromethamine tablets in pediatric patients.
Postmarketing Surveillance Study
A large postmarketing observational, non-randomized study, involving approximately 10,000 patients receiving Ketorolac Tromethamine, demonstrated that the risk of clinically serious gastrointestinal (G.I.) bleeding was dose-dependent (see Table 3A and 3B.) This was particularly true in elderly patients who received an average dose greater than 60 mg/day of Ketorolac Tromethamine (Table 3A).
Table 3 Incidence of Clinically Serious G.I. Bleeding as Related to Age, Total Daily Dose, and History of G.I. Perforation, Ulcer, Bleeding (PUB) after up to 5 Days of Treatment with Ketorolac Tromethamine Injection
A. Patients without History of PUB
|
Age of Patients
|
Total Daily Dose of Ketorolac Tromethamine Injection
|
≤60 mg
|
>60 to 90 mg
|
>90 to 120 mg
|
>120 mg
|
|
<65 years of age
|
0.4%
|
0.4%
|
0.9%
|
4.6%
|
≥65 years of age
|
1.2%
|
2.8%
|
2.2%
|
7.7%
|
B. Patients with History of PUB
|
Age of Patients
|
Total Daily Dose of Ketorolac Tromethamine Injection
|
≤60 mg
|
>60 to 90 mg
|
>90 to 120 mg
|
>120 mg
|
|
<65 years of age
|
2.1%
|
4.6%
|
7.8%
|
15.4%
|
≥65 years of age
|
4.7%
|
3.7%
|
2.8%
|
25%
|
Indications and Usage for Ketorolac Tromethamine
Adult Patients: Ketorolac Tromethamine is indicated for the short-term (≤5 days) management of moderately severe, acute pain that requires analgesia at the opioid level, usually in a postoperative setting. Therapy should always be initiated with IV or IM Ketorolac Tromethamine, and the oral dosage form is to be used only as continuation treatment, if necessary. Combined use of IV/IM and the oral dosage form is not to exceed 5 days of use because of the potential of increasing the frequency and severity of adverse reactions associated with the recommended doses (see WARNINGS, PRECAUTIONS, DOSAGE AND ADMINISTRATION, and ADVERSE REACTIONS). Patients should be switched to alternative analgesics as soon as possible, but Ketorolac Tromethamine therapy is not to exceed 5 days.
Pediatric Patients: The safety and effectiveness of single doses of Ketorolac Tromethamine injection have been established in pediatric patients between the ages of 2 and 16 years. Ketorolac Tromethamine as a single injectable dose, has been shown to be effective in the management of moderately severe acute pain that requires analgesia at the opioid level, usually in the postoperative setting. There is limited data available to support the use of multiple doses of Ketorolac Tromethamine injection in pediatric patients. Safety and effectiveness have not been established in pediatric patients below the age of 2 years. Use of Ketorolac Tromethamine injection in pediatric patients is supported by evidence from adequate and well-controlled studies of Ketorolac Tromethamine injection in adults with additional pharmacokinetic, efficacy and safety data on its use in pediatric patients available in the published literature (see CLINICAL PHARMACOLOGY: Clinical Studies, WARNINGS, and PRECAUTIONS).
Ketorolac Tromethamine injection has been used concomitantly with morphine and meperidine and has shown an opioid-sparing effect. For breakthrough pain, it is recommended to supplement the lower end of the Ketorolac Tromethamine injection dosage range with low doses of narcotics prn, unless otherwise contraindicated. Ketorolac Tromethamine and narcotics should not be administered in the same syringe (see DOSAGE AND ADMINISTRATION − Pharmaceutical Information for Ketorolac Tromethamine Injection).
Contraindications
(see also Boxed WARNING)
Ketorolac Tromethamine is CONTRAINDICATED in labor and delivery because, through its prostaglandin synthesis inhibitory effect, it may adversely affect fetal circulation and inhibit uterine contractions, thus increasing the risk of uterine hemorrhage.
Ketorolac Tromethamine inhibits platelet function and is, therefore, CONTRAINDICATED in patients with suspected or confirmed cerebrovascular bleeding, hemorrhagic diathesis, incomplete hemostasis, and those at high risk of bleeding (see WARNINGS and PRECAUTIONS).
Warnings
(see also Boxed WARNING)
► The combined use of Ketorolac Tromethamine injection and Ketorolac Tromethamine tablets is not to exceed 5 days in adults. Only single doses of Ketorolac Tromethamine injection are recommended for use in pediatric patients.
The most serious risks associated with Ketorolac Tromethamine are:
Gastrointestinal (GI) Effects − Risk of GI Ulceration, Bleeding and Perforation: Ketorolac Tromethamine is CONTRAINDICATED in patients with previously documented peptic ulcers and/or G.I. bleeding. Serious gastrointestinal toxicity, such as bleeding, ulceration, and perforation, can occur at any time, with or without warning symptoms, in patients treated with Ketorolac Tromethamine. Studies to date with NSAIDs have not identified any subset of patients not at risk of developing peptic ulceration and bleeding. Elderly or debilitated patients seem to tolerate ulceration or bleeding less well than other individuals, and most spontaneous reports of fatal G.I. events are in this population. Postmarketing experience with parenterally administered Ketorolac Tromethamine suggests that there may be a greater risk of gastrointestinal ulcerations, bleeding and perforation in the elderly.
The incidence and severity of gastrointestinal complications increases with increasing dose of, and duration of treatment with Ketorolac Tromethamine. In a non-randomized, in-hospital postmarketing surveillance study, comparing Ketorolac Tromethamine injection to parenteral opioids, higher rates of clinically serious G.I. bleeding were seen in patients <65 years of age who received an average total daily dose of more than 90 mg of Ketorolac Tromethamine injection per day (see CLINICAL PHARMACOLOGY − Postmarketing Surveillance Study).
The same study showed that elderly (≥65 years of age), and debilitated patients are more susceptible to gastrointestinal complications. A history of peptic ulcer disease was revealed as another risk factor that increases the possibility of developing serious gastrointestinal complications during Ketorolac Tromethamine therapy (see Tables 3A and 3B).
Hemorrhage: Because prostaglandins play an important role in hemostasis, and NSAIDs affect platelet aggregation as well, use of Ketorolac Tromethamine in patients who have coagulation disorders should be undertaken very cautiously, and those patients should be carefully monitored. Patients on therapeutic doses of anticoagulants (e.g., heparin or dicumarol derivatives) have an increased risk of bleeding complications if given Ketorolac Tromethamine concurrently; therefore, physicians should administer such concomitant therapy only extremely cautiously. The concurrent use of Ketorolac Tromethamine and prophylactic low-dose heparin (2500 to 5000 units q12h), warfarin and dextrans have not been studied extensively, but may also be associated with an increased risk of bleeding. Until data from such studies are available, physicians should carefully weigh the benefits against the risks, and use such concomitant therapy in these patients only extremely cautiously. In patients who receive anticoagulants for any reason, there is an increased risk of intramuscular hematoma formation from IM administered Ketorolac Tromethamine (see PRECAUTIONS − Drug Interactions). Patients receiving therapy that affects hemostasis should be monitored closely.
In postmarketing experience, postoperative hematomas and other signs of wound bleeding have been reported in association with the perioperative use of Ketorolac Tromethamine injection. Therefore, perioperative use of Ketorolac Tromethamine should be avoided and postoperative use be undertaken with caution when hemostasis is critical (see WARNINGS and PRECAUTIONS).
Pediatrics and Tonsillectomy: Physicians should consider the increased risk of bleeding before deciding to administer Ketorolac Tromethamine injection in patients following tonsillectomy. Ketorolac Tromethamine injection is not recommended for use in pediatric patients below the age of 2 years. In a retrospective analysis of patients having undergone tonsillectomy with or without adenoidectomy, the risk of bleeding was 10.1% in patients administered Ketorolac Tromethamine injection compared to 2.2% in those receiving opioids. The postoperative hemorrhage rate in patients 12 years and younger was 6.5% and 3.3% with and without Ketorolac Tromethamine injection, respectively. In a prospective study of Ketorolac Tromethamine injection in pediatric patients (ages 3 to 9 years) undergoing tonsillectomy with or without adenoidectomy, the overall incidence of bleeding was similar between the patients receiving Ketorolac Tromethamine injection and morphine (16.3% versus 17%, respectively). However, during the first 24 hours after surgery, a higher incidence of bleeding was observed in the Ketorolac Tromethamine injection group (14.3%) versus the morphine group (4.2%).
Anaphylactoid Reactions: Anaphylactoid reactions may occur in patients without a known previous exposure or hypersensitivity to aspirin, Ketorolac Tromethamine, or other NSAIDs, or in individuals with a history of angioedema, bronchospastic reactivity (e.g., asthma), and nasal polyps. Anaphylactoid reactions, like anaphylaxis, may have a fatal outcome.
Impaired Renal Function: Ketorolac Tromethamine should be used with caution in patients with impaired renal function, or a history of kidney disease because it is a potent inhibitor of prostaglandin synthesis. Renal toxicity with Ketorolac Tromethamine has been seen in patients with conditions leading to a reduction in blood volume and/or renal blood flow where renal prostaglandins have a supportive role in the maintenance of renal perfusion. In these patients, administration of Ketorolac Tromethamine may cause a dose-dependent reduction in renal prostaglandin formation and may precipitate acute renal failure. Patients at greatest risk of this reaction are those with impaired renal function, dehydration, heart failure, liver dysfunction, those taking diuretics and the elderly. Discontinuation of Ketorolac Tromethamine therapy is usually followed by recovery to the pretreatment state.
Renal Effects: Ketorolac Tromethamine and its metabolites are eliminated primarily by the kidneys, which, in patients with reduced creatinine clearance, will result in diminished clearance of the drug (see CLINICAL PHARMACOLOGY). Therefore, Ketorolac Tromethamine should be used with caution in patients with impaired renal function (see DOSAGE AND ADMINISTRATION) and such patients should be followed closely. With the use of Ketorolac Tromethamine, there have been reports of acute renal failure, interstitial nephritis, and nephrotic syndrome.
Because patients with underlying renal insufficiency are at increased risk of developing acute renal failure, the risks and benefits should be assessed prior to giving Ketorolac Tromethamine to these patients. Hence, in patients with moderately elevated serum creatinine, it is recommended that the daily dose of Ketorolac Tromethamine injection be reduced by half, not to exceed 60 mg/day. Ketorolac Tromethamine is CONTRAINDICATED IN PATIENTS WITH SERUM CREATININE CONCENTRATIONS INDICATING ADVANCED RENAL IMPAIRMENT (see CONTRAINDICATIONS).
Hypovolemia should be corrected before treatment with Ketorolac Tromethamine is initiated.
Fluid Retention and Edema: Fluid retention, edema, retention of NaCl, oliguria, elevations of serum urea nitrogen and creatinine have been reported in clinical trials with Ketorolac Tromethamine. Therefore, Ketorolac Tromethamine should be used only very cautiously in patients with cardiac decompensation, hypertension, or similar conditions.
Precautions
GENERAL
Hepatic Effects: Ketorolac Tromethamine should be used with caution in patients with impaired hepatic function, or a history of liver disease. Treatment with Ketorolac Tromethamine may cause elevations of liver enzymes, and in patients with pre-existing liver dysfunction it may lead to the development of a more severe hepatic reaction. The administration of Ketorolac Tromethamine should be discontinued in patients in whom an abnormal liver test has occurred as a result of Ketorolac Tromethamine therapy.
Hematologic Effects: Ketorolac Tromethamine inhibits platelet aggregation and may prolong bleeding time; therefore, it is contraindicated as a pre-operative medication, and caution should be used when hemostasis is critical. Unlike aspirin, the inhibition of platelet function by Ketorolac Tromethamine disappears within 24 to 48 hours after the drug is discontinued. Ketorolac Tromethamine does not appear to affect platelet count, prothrombin time (PT) or partial thromboplastin time (PTT). In controlled clinical studies, where Ketorolac Tromethamine was administered intramuscularly or intravenously postoperatively, the incidence of clinically significant postoperative bleeding was 0.4% for Ketorolac Tromethamine compared to 0.2% in the control groups receiving narcotic analgesics.
INFORMATION FOR PATIENTS
Ketorolac Tromethamine is a potent NSAID and may cause serious side effects such as gastrointestinal bleeding or kidney failure, which may result in hospitalization and even fatal outcome.
Physicians, when prescribing Ketorolac Tromethamine, should inform their patients or their guardians of the potential risks of Ketorolac Tromethamine treatment (see Boxed WARNING, WARNINGS, PRECAUTIONS, and ADVERSE REACTIONS sections). Advise patients not to give ketorolac tromethamine tablets to other family members and to discard any unused drug.
Remember that the total duration of ketorolac tromethamine therapy is not to exceed 5 (five) days in adults or a single dose in pediatric patients ages 2 to 16 years.
DRUG INTERACTIONS
Ketorolac is highly bound to human plasma protein (mean 99.2%).
Warfarin, Digoxin, Salicylate and Heparin
The in vitro binding of warfarin to plasma proteins is only slightly reduced by Ketorolac Tromethamine (99.5% control vs 99.3%) when ketorolac plasma concentrations reach 5 to 10 mcg/mL. Ketorolac does not alter digoxin protein binding. In vitro studies indicate that, at therapeutic concentrations of salicylate (300 mcg/mL), the binding of ketorolac was reduced from approximately 99.2% to 97.5%, representing a potential two-fold increase in unbound ketorolac plasma levels. Therapeutic concentrations of digoxin, warfarin, ibuprofen, naproxen, piroxicam, acetaminophen, phenytoin, and tolbutamide did not alter Ketorolac Tromethamine protein binding.
In a study involving 12 volunteers, Ketorolac Tromethamine tablets were co-administered with a single dose of 25 mg warfarin, causing no significant changes in pharmacokinetics or pharmacodynamics of warfarin. In another study, Ketorolac Tromethamine injection was given with two doses of 5000 U of heparin to 11 healthy volunteers, resulting in a mean template bleeding time of 6.4 minutes (3.2 to 11.4 min) compared to a mean of 6.0 minutes (3.4 to 7.5 min) for heparin alone and 5.1 minutes (3.5 to 8.5 min) for placebo. Although these results do not indicate a significant interaction between Ketorolac Tromethamine and warfarin or heparin, the administration of Ketorolac Tromethamine to patients taking anticoagulants should be done extremely cautiously, and patients should be closely monitored (see WARNINGS and PRECAUTIONS).
Furosemide
Ketorolac Tromethamine administered IV or IM reduced the diuretic response to furosemide in normovolemic healthy subjects by approximately 20% (mean sodium and urinary output decreased 17%).
Probenecid
Concomitant administration of Ketorolac Tromethamine tablets and probenecid resulted in decreased clearance of ketorolac and significant increases in ketorolac plasma levels (total AUC increased approximately 3-fold from 5.4 to 17.8 mcg/h/mL) and terminal half-life increased approximately 2-fold from 6.6 to 15.1 hours. Therefore, concomitant use of Ketorolac Tromethamine and probenecid is contraindicated.
Lithium
Inhibition of renal lithium clearance, leading to an increase in plasma lithium concentration, has been reported with some prostaglandin synthesis-inhibiting drugs. The effect of Ketorolac Tromethamine on plasma lithium has not been studied, but cases of increased lithium plasma levels during Ketorolac Tromethamine therapy have been reported.
Methotrexate
Concomitant administration of methotrexate and some NSAIDs has been reported to reduce the clearance of methotrexate, enhancing the toxicity of methotrexate. The effect of Ketorolac Tromethamine on methotrexate clearance has not been studied.
Nondepolarizing Muscle Relaxants
In postmarketing experience, there have been reports of a possible interaction between Ketorolac Tromethamine injection and nondepolarizing muscle relaxants that resulted in apnea. The concurrent use of Ketorolac Tromethamine with muscle relaxants has not been formally studied.
ACE Inhibitors
Concomitant use of ACE inhib
