Ketorolac Tromethamine

Introduction Overview

Generic Name

Brand Name

Toradol

Dosage Form

Injection, solution (intravenous and intramuscular)

Drug Class

Nonsteroidal anti-inflammatory drugs (NSAIDs)

Pharmacokinetics

Ketorolac Tromethamine is a racemic mixture composed of the S-enantiomer, which exerts the analgesic effect, and the R-enantiomer. Pharmacokinetic profiles reveal the drug’s linear kinetics across administration routes, with no change in clearance over multiple dosing. Extensive details are outlined below:

Absorption:
Ketorolac exhibits rapid and complete bioavailability (~100%) following oral and intramuscular administration, comparable to intravenous bolus. Peak plasma concentrations (Cmax) occur within 30 to 45 minutes after intramuscular injection and oral administration, whereas intravenous administration yields almost immediate plasma peaks (within 1 to 3 minutes). This rapid absorption allows prompt onset of analgesic activity, typically within 30 minutes post-dosing, and peak effects around 1 to 2 hours.

Distribution:
Following absorption, ketorolac distributes widely with an apparent volume of distribution after complete distribution of approximately 13 liters in adults. It is highly bound to plasma proteins (~99%), predominantly albumin, with plasma concentrations up to 10 mcg/mL occupying only 5% of albumin sites, suggesting unbound fraction remains stable in therapeutic range. In conditions of hypoalbuminemia (e.g., liver disease), free drug concentrations may increase. Ketorolac also crosses into breast milk at very low concentrations (~0.025-0.037 milk-plasma ratio), resulting in minimal infant exposure.

Metabolism:
Ketorolac undergoes extensive hepatic metabolism primarily via hydroxylation and conjugation to inactive metabolites. The metabolic pathways do not exhibit induction or inhibition by ketorolac itself. There is minimal interconversion between enantiomers, maintaining distinct pharmacokinetic clearance rates between S- and R-forms.

Elimination:
Renal excretion represents the major elimination pathway, accounting for approximately 92% of the dose, with 60% excreted unchanged and 40% as metabolites. Fecal excretion constitutes about 6%. Half-life varies between enantiomers: approximately 2.5 hours for the S-enantiomer and 5 hours for the R-enantiomer, with the racemate having a 5-6 hour half-life. Clearance is reduced, and half-life prolonged in renal impairment, necessitating dose adjustments. Accumulation is minimal after repeated dosing every 6 hours, reaching steady state around the fourth dose. Special populations such as elderly, renal and hepatic impairment, and pediatric patients exhibit altered pharmacokinetics requiring clinical vigilance.

Dosage Forms

Available Dosage Forms:
Ketorolac tromethamine is available exclusively as sterile injection solutions for intramuscular and intravenous use. The commercial preparations include:
- 15 mg/mL in 1 mL single-dose vials (1.5% solution)
- 30 mg/mL in 1 mL single-dose vials (3% solution)
- 60 mg/2 mL in 2 mL single-dose vials (3% solution, for intramuscular use only)
These solutions contain approximately 10% alcohol (w/v) and varying amounts of sodium chloride to maintain isotonicity; pH ranges from 6.9 to 7.9 adjusted with sodium hydroxide or hydrochloric acid.

Dosages for Adults and Adolescents:
- Single-dose intramuscular:
- Patients <65 years: 60 mg.
- Patients ≥65 years, renally impaired, or <50 kg: 30 mg.
- Single-dose intravenous:
- Patients <65 years: 30 mg.
- Patients ≥65 years, renally impaired, or <50 kg: 15 mg.
- Multiple-dose (IV or IM) therapy:
- Patients <65 years: 30 mg every 6 hours, not to exceed 120 mg/day.
- Patients ≥65 years, renally impaired, or <50 kg: 15 mg every 6 hours, not to exceed 60 mg/day.
Oral ketorolac tablets are indicated only as continuation therapy following parenteral use and the combined total duration of therapy (oral plus injection) should not exceed 5 days.

Specific Patient Populations:
- Elderly patients require dosing adjustments due to decreased clearance and increased sensitivity; doses should not exceed 60 mg/day.
- Patients with renal impairment demonstrate prolonged half-life and reduced clearance; ketorolac is contraindicated in advanced renal impairment and should be used cautiously with dose reduction in moderate impairment.
- Pediatric use is not approved; safety and efficacy have not been established in patients under 17 years.
- Intramuscular 60 mg dose is restricted to single administration only.

Clinical guidelines emphasize using the lowest effective dose for the shortest duration (maximum 5 days) to reduce the risk of serious adverse events including gastrointestinal and renal complications.

Mechanism Of Action

Ketorolac tromethamine acts predominantly as a non-selective inhibitor of cyclooxygenase enzymes COX-1 and COX-2, leading to decreased synthesis of prostaglandins, key mediators of inflammation, pain, and fever. This inhibition reduces prostaglandin-mediated sensitization of nociceptors and inflammatory processes, providing effective analgesic and anti-inflammatory effects.

At the molecular level, ketorolac competitively binds to the active sites of both COX isoforms, preventing conversion of arachidonic acid to prostaglandin H2, the precursor of pro-inflammatory prostaglandins and thromboxanes. The S-enantiomer exhibits the primary biological activity responsible for analgesia, indicating stereospecific enzyme binding.

Cellular pathways affected include decreased prostaglandin-mediated vasodilation, edema, and leukocyte infiltration, which contribute to pain and swelling reduction. By inhibiting platelet aggregation via COX-1 blockade and subsequent thromboxane A2 synthesis inhibition, ketorolac also exerts an antiplatelet effect, impacting hemostasis.

Clinically, ketorolac provides analgesia comparable to opioid analgesics for moderately severe acute pain, particularly postoperative pain, without sedative or anxiolytic properties. Compared with other NSAIDs, ketorolac is notable for its potent analgesic efficacy relative to its anti-inflammatory properties, making it useful for short-term opioid-level analgesia.

Research and clinical trials have demonstrated rapid onset and effective pain control, with the analgesic peak within 2 to 3 hours post administration. However, the risk profile mandates limiting duration of use to mitigate gastrointestinal, renal, and cardiovascular adverse events.

Pharmacological Actions

Non-selective inhibition of cyclooxygenase enzymes (COX-1 and COX-2), reducing prostaglandin synthesis
Analgesic activity effective for moderately severe acute pain at opioid-sparing dose levels
Anti-inflammatory effects through inhibition of prostaglandin-mediated inflammation
Antipyretic effects by reducing hypothalamic prostaglandin synthesis
Inhibition of platelet aggregation via thromboxane A2 suppression
Rapid onset of analgesia within approximately 30 minutes of parenteral administration
Lack of sedative or anxiolytic properties, allowing use without CNS depression
Linear pharmacokinetics enabling predictable dosing in adults
Highly protein bound (~99%), with stable unbound fraction across therapeutic range
Metabolized hepatically with renal excretion of unchanged drug and metabolites
Dose-dependent risk for gastrointestinal ulceration, bleeding, and renal toxicity
Increases risk of serious cardiovascular thrombotic events, especially with extended use or higher doses
Prostaglandin inhibition may impair renal perfusion especially in compromised patients
Potential to interact adversely with anticoagulants, diuretics, and other nephrotoxic agents
Exerts effects via the S-enantiomer, with stereoselective pharmacodynamics

Therapeutic Or Clinical Uses

Short-term management (≤5 days) of moderately severe acute pain requiring opioid-level analgesia
Postoperative pain control following surgical procedures
Bridging analgesia transitioning from intravenous/intramuscular to oral therapy
Alternative or adjunct to opioid analgesics to reduce opioid consumption
Management of acute musculoskeletal injuries with severe pain
Utilized when non-opioid analgesics are insufficient for acute pain relief
Suitable for adult patients without contraindications to NSAIDs or ketorolac
Effective for analgesia in inpatient and ambulatory settings
Not indicated for minor or chronic painful conditions
Use restricted in special populations due to renal and gastrointestinal risks
Not approved for pediatric use under 17 years of age
Employed in clinical settings requiring rapid onset analgesia
Off-label use discouraged due to safety profile and limited duration of approval
Avoided in patients undergoing coronary artery bypass graft surgery
Used cautiously in elderly and those with pre-existing renal or cardiovascular disease

Side Or Adverse Effects

Gastrointestinal disturbances including abdominal pain, dyspepsia, nausea, vomiting
Gastrointestinal ulcers, bleeding, and perforation which may be fatal
Increased bleeding time due to platelet function inhibition
Renal adverse events such as acute renal failure, interstitial nephritis, and nephrotic syndrome
Headache and dizziness
Edema and fluid retention
Hypertension and exacerbation of heart failure symptoms
Rashes, pruritus, purpura, and other dermatologic reactions including severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis)
Anemia from blood loss or impaired erythropoiesis
Elevated liver enzymes and rare instances of severe hepatic reactions including hepatitis and liver failure
Hypersensitivity reactions ranging from bronchospasm to anaphylaxis
Tinnitus and hearing disturbances
Postoperative hematomas and wound bleeding
Rare neurological symptoms, including confusion, hallucinations, and tremors
Other hematologic effects including leukopenia, thrombocytopenia, eosinophilia

Precautions

Limit duration of therapy to 5 days to reduce risk of serious adverse events
Avoid use in patients with active peptic ulcer disease or recent gastrointestinal bleeding
Use cautiously in elderly patients due to increased risk of gastrointestinal and renal toxicity
Monitor renal function, especially in patients with pre-existing renal impairment, heart failure, or volume depletion
Avoid concomitant use with other NSAIDs or aspirin to reduce additive toxicity
Adjust dose in patients ≥65 years, those with renal impairment, or low body weight (<50 kg)
Use with caution in patients with hepatic impairment; monitor liver function tests
Avoid use in patients with a history of asthma exacerbated by NSAIDs or aspirin sensitivity
Do not use as prophylactic analgesic before major surgery or in labor and delivery
Be vigilant for signs of serious skin reactions and discontinue if rash or fever develops
Monitor blood pressure closely during therapy due to risk of hypertension
Use caution in patients on anticoagulants or antiplatelet drugs; monitor bleeding parameters
Monitor hematologic parameters during prolonged treatment for anemia or blood dyscrasias
Inform patients about the signs of cardiovascular events and gastrointestinal bleeding
Ensure hypovolemia is corrected prior to administration to minimize renal risk

Warnings

Maximum combined duration of oral and parenteral ketorolac use must not exceed 5 days due to increased risk of GI, renal, and cardiovascular adverse events
Ketorolac is contraindicated in patients with advanced renal impairment and those at risk for renal failure due to volume depletion
Increased risk of serious cardiovascular thrombotic events including myocardial infarction and stroke, which can be fatal
Contraindicated in the setting of coronary artery bypass graft (CABG) surgery
Risk of serious gastrointestinal bleeding, ulceration, and perforation occurring at any time during treatment without warning
Ketorolac inhibits platelet aggregation, increasing bleeding risk; contraindicated in patients with active bleeding or high bleeding risk
Hypersensitivity reactions, including anaphylaxis and bronchospasm, have been reported; contraindicated in patients with aspirin or NSAID allergy
Serious skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis may occur and can be fatal
Use in pregnancy beyond 30 weeks gestation is contraindicated due to risk of premature closure of fetal ductus arteriosus
Potential for fluid retention and edema; avoid in severe heart failure unless benefits outweigh risks
May impair renal function, particularly in susceptible individuals
Avoid concomitant use with probenecid and pentoxifylline due to contraindications and increased bleeding risk
Should not be administered via intrathecal or epidural routes due to alcohol content
Avoid use in labor and delivery due to adverse effects on fetal circulation and uterine contractions
Concurrent aspirin use may increase risk of GI adverse events without mitigating cardiovascular risks

Contraindication

Known hypersensitivity to ketorolac tromethamine or any components of the formulation
Active peptic ulcer disease or recent gastrointestinal bleeding or perforation
History of NSAID-induced asthma, urticaria, or allergic-type reactions including bronchospasm
Use as prophylactic analgesic before any major surgery
Coronary artery bypass graft (CABG) surgery
Advanced renal impairment or patients at risk of renal failure due to volume depletion
Labor and delivery due to risk of fetal toxicity and uterine hemorrhage
Suspected or confirmed cerebrovascular bleeding, hemorrhagic diathesis, incomplete hemostasis, or high risk of bleeding
Concurrent treatment with aspirin or other NSAIDs
Concomitant use with probenecid or pentoxifylline
Intrathecal or epidural administration due to presence of alcohol content
Previous serious skin reactions to NSAIDs (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis)

Drug Interactions

Increased bleeding risk when used with anticoagulants such as warfarin and heparin; concurrent use requires extreme caution and monitoring
Reduced protein binding and increased unbound ketorolac levels when coadministered with aspirin; combined use generally not recommended
NSAIDs, including ketorolac, may reduce the efficacy of diuretics like furosemide and thiazides, and can precipitate renal failure
Probenecid significantly increases ketorolac plasma concentration and half-life; concomitant use is contraindicated
Lithium levels may be elevated due to reduced renal clearance when combined with NSAIDs; monitor closely for lithium toxicity
Concurrent use with methotrexate may enhance methotrexate toxicity; use with caution
ACE inhibitors and angiotensin receptor blockers' antihypertensive effects may be attenuated by ketorolac; increased risk of renal impairment especially in volume-depleted patients
Concomitant therapy with pentoxifylline increases bleeding tendency; contraindicated
Possible increased risk of seizures reported with concurrent use of antiepileptic drugs such as phenytoin and carbamazepine
Potential for enhanced CNS adverse effects including hallucinations when used with psychoactive drugs (e.g., fluoxetine, thiothixene, alprazolam)
Concurrent use with selective serotonin reuptake inhibitors (SSRIs) increases gastrointestinal bleeding risk
No significant interaction with digoxin, salicylate, ibuprofen, naproxen, piroxicam, acetaminophen, phenytoin, or tolbutamide observed
Not recommended to mix ketorolac in small volumes with morphine sulfate, meperidine, promethazine, or hydroxyzine due to precipitation
Potential additive nephrotoxicity when combined with other nephrotoxic agents

Preparations Of The Drug

Ketorolac Tromethamine Injection, USP sterile solutions for parenteral use
Formulations: - 15 mg/mL in 1 mL single-dose vials (1.5% solution) - 30 mg/mL in 1 mL single-dose vials (3% solution) - 60 mg/2 mL in 2 mL single-dose vials (3% solution, intramuscular use only)
Solutions contain 10% (w/v) alcohol as a solvent
Contains sodium chloride for isotonicity (6.68 mg/mL in 15 mg vials, 4.35 mg/mL in 30 mg vials, and 8.7 mg/2 mL in 60 mg vials)
pH adjusted to 6.9–7.9 with sodium hydroxide or hydrochloric acid
Provided in single-dose glass fliptop vials to maintain sterility and stability
Dispensed in trays or cartons containing 25 vials each
Storage conditions: Room temperature 20–25°C (68–77°F), protect from light
Distributed by Hospira, Inc., Lake Forest, IL, USA
Not for mixing in small volumes with certain other drugs due to precipitation risks
Labels clearly indicate route of administration (IV/IM) and dose strength
Required to be visually inspected for particulate matter and discoloration prior to administration
Packaging includes vial labels, trays, and cartons with unique National Drug Code (NDC) identifiers