Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID). Although most familiar in its oral form, ibuprofen can also be administered as an intravenous (IV) medication for more rapid effects. IV ibuprofen is approved in the US as an analgesic (pain reliever) and antipyretic (fever reducer).
Ibuprofen’s main action within the body is the inhibition of prostaglandin synthesis. Prostaglandins are pro-inflammatory chemical signals that increase blood vessel permeability, recruit immune cells and promote edema (fluid accumulation). They also make pain receptors more sensitive to stimulation. Additionally, a prostaglandin synthesized in the hypothalamus (a region of the brain that works to maintain body homeostasis), PGE2, is a mediator of fever. Ibuprofen blocks prostaglandin synthesis by inhibiting the cyclooxygenas enzymes COX1 and COX2; it thus has anti-inflammatory, analgesic and antipyretic action. Additional pathways through which ibuprofen may act are still being explored. One interesting theory is that ibuprofen may be able to activate the brain’s cannabinoid receptors, which would decrease the perception of pain.
IV ibuprofen is often used with opioid medication as a multi-modal treatment plan for pain after surgery. Opioids are very strong pain relievers; however, they have a high risk of dependence and misuse, as well as other adverse effects such as medication interactions. They also do not address any underlying cause of pain, whereas NSAIDs are able to decrease inflammation. IV NSAIDs ketorolac and diclofenac are also approved in the US for pain relief but ibuprofen is the only IV NSAID currently approved for both pain relief and fever reduction.
IV ibuprofen has been shown to reduce the quantity of opioids required by a patient when compared to a placebo and other drugs like acetaminophen. Its use decreases patients’ subjective levels of pain as well as measurable levels of stress hormones in the postoperative period. Studies report that ibuprofen is well tolerated by patients and that there is no statistically significant increase in severe adverse events when compared with a placebo. It is also well-tolerated as a rapid infusion, given over 5-10 minutes.
Although generally considered safe, NSAIDs, including ibuprofen, have some side effects related to the inhibition of COX1 and COX2, which contribute to other processes throughout the body besides prostaglandin synthesis. Inhibition of COX1 is related to gastrointestinal (GI) symptoms and long-term inhibition of COX2 may have cardiovascular risks. Ibuprofen is not selective for either COX1 or COX2, as compared with ketorolac which is more selective for COX1 and diclofenac which is more selective for COX2. Ibuprofen thus may have a more favorable risk profile in terms of GI and cardiovascular complications.
IV ibuprofen may also have impacts on the effectiveness of other medications that patients take concurrently. Low dose aspirin, used for antiplatelet therapy to prevent stroke and heart attack, may be less effective since ibuprofen can block platelet COX1. This can also increase bleeding risk if patients are being given other anticoagulants or selective serotonin reuptake inhibitors (SSRI’s). Ibuprofen may also decrease effectiveness of antihypertensive drugs, since the inhibition of prostaglandins in the kidney tubules causes the blood vessels to constrict, a mechanism of hypertension. Finally, patients taking lithium need to have their serum lithium levels monitored, since NSAIDS reduce lithium clearance from the body and can lead to toxic levels in the blood.