Ketorolac

Pharmaceuticals

Pharmaceuticals -> Analgesics and anti-inflammatories

2.1

2.72

Breast Feeding; Lactation; Milk, Human; Analgesic Agents; Anti-inflammatory Agents, Nonsteroidal

Pharmaceuticals

162-165 °C (tromethamine salt)

165 - 167 °C (tromethamine salt)

3.49

3.5

Danger

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

P261, P264, P264+P265, P270, P271, P280, P301+P316, P302+P352, P304+P340, P305+P351+P338, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 7 reports by companies from 3 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Prospective studies show that up to 1% of patients taking ketorolac experience at least transient serum aminotransferase elevations. These may resolve even with drug continuation. Marked aminotransferase elevations above 3 times the upper limit of normal (ULN) occur in less than 1% of patients. Clinically apparent liver injury with jaundice from ketorolac has not been described in any detail so that the latency, clinical features and prognosis of injury is unknown. Ketorolac is not mentioned as an etiologic agent in large case series on drug induced liver injury or acute liver failure from the United States. However, the antiplatelet activity of ketorolac can lead to complications mostly due to platelet dysfunction and bleeding, and several instances of hepatic rupture and subcapsular hepatic hematomas have been reported with its use which might present clinically as acute liver injury.

High quantities or prolonged use of ketorolac can lead to hepatotoxicity and nephrotoxicity. In addition, ketorolac can cause multiple skin disorders, such as toxic epidermal necrolysis. Anaphylactic shock has been characterized due to ketorolac overdose.

Benchmark Dataset for the Liver Toxicity Knowledge Base (LTKB)

ketorolac

Toradol®

NSAIDs

3

less-DILI-concern drugs

S01BC05

M - Musculo-skeletal system

S - Sensory organs

QM - Musculo-skeletal system

QS - Sensory organs

Ketorolac is a non-selective NSAID and acts by inhibiting both COX-1 and COX-2 enzymes which are normally responsible for converting arachidonic acid to prostaglandins. The COX-1 enzyme is constitutively active and can be found in platelets, gastric mucosa, and vascular endothelium. On the other hand, the COX-2 enzyme is inducible and mediates inflammation, pain and fever. As a result, inhibition of the COX-1 enzyme is linked to an increased risk of bleeding and risk of gastric ulceration, while the desired anti-inflammatory and analgesic properties are linked to inhibition of the COX-2 enzyme. Therefore, despite it's effectiveness in pain management, ketorolac should not be used long-term since this increases the risk of serious adverse effects such as gastrointestinal bleeding, peptic ulcers, and perforations.

Ketorolac inhibits key pathways in prostaglandin synthesis which is crucial to it's mechanism of action. Although ketorolac is non-selective and inhibits both COX-1 and COX-2 enzymes, it's clinical efficacy is derived from it's COX-2 inhibition. The COX-2 enzyme is inducible and is responsible for converting arachidonic acid to prostaglandins that mediate inflammation and pain. By blocking this pathway, ketorolac achieves analgesia and reduces inflammation. Ketorolac is administered as a racemic mixture; however, the "S" enantiomer is largely responsible for it's pharmacological activity.

Ketorolac tromethamine is administered as a racemic mixture, therefore the half-life of each enantiomer must be considered. The half life of the S-enantiomer is ~2.5 hours, while the half life of the R-enantiomer is ~5 hours. Based on this data, the S enantiomer is cleared about twice as fast as the R enantiomer.

Ketorolac is heavily metabolized via hydroxylation or conjugation in the liver; however, it appears that the key metabolic pathway is glucuronic acid conjugation. Enzymes involved in phase I metabolism include CYP2C8 and CYP2C9, while phase II metabolism is carried out by UDP-glucuronosyltransferase (UGT) 2B7.

YZI5105V0L

KETOROLAC

Mechanisms of Action [MoA] - Cyclooxygenase Inhibitors

Chemical Structure [CS] - Anti-Inflammatory Agents, Non-Steroidal

Established Pharmacologic Class [EPC] - Nonsteroidal Anti-inflammatory Drug

Established Pharmacologic Class [EPC] - Cyclooxygenase Inhibitor

Anti-inflammatory agents that are non-steroidal in nature. In addition to anti-inflammatory actions, they have analgesic, antipyretic, and platelet-inhibitory actions. They act by blocking the synthesis of prostaglandins by inhibiting cyclooxygenase, which converts arachidonic acid to cyclic endoperoxides, precursors of prostaglandins. Inhibition of prostaglandin synthesis accounts for their analgesic, antipyretic, and platelet-inhibitory actions; other mechanisms may contribute to their anti-inflammatory effects.

Compounds or agents that combine with cyclooxygenase (PROSTAGLANDIN-ENDOPEROXIDE SYNTHASES) and thereby prevent its substrate-enzyme combination with arachidonic acid and the formation of eicosanoids, prostaglandins, and thromboxanes.

Ketorolac is rapidly, and completely absorbed after oral administration with a bioavailability of 80% after oral administration. Cmax is attained 20-60 minutes after administration, and after intramuscular administration, the area under the plasma concentration-time curve (AUC) is proportional to the dose administered. After intramuscular administration, ketorolac demonstrates a time to maximal plasma concentration (tmax) of approximately 45-50 minutes, and a tmax of 30-40 minutes after oral administration. The rate of absorption may be reduced by food; however, the extent of absorption remains unaffected.

Ketorolac is primarily renally eliminated and approximately 92% of the dose can be recovered in the urine with 60% of this proportion recovered unchanged, and 40% recovered as metabolites. In addition 6% of a single dose is eliminated in the feces.

The apparent volume of distribution of ketorolac in healthy human subjects is 0.25 L/kg or less.

The plasma clearance of ketorolac is 0.021 to 0.037 L/h/kg. Further, studies have illustrated that clearance of oral, IM and IV doses of ketorolac are comparable which suggests linear kinetics. It should also be noted that clearance in children is about double the clearance found in adults.