#ivtylenol

Oral tylenol has been used for centuries in the treatment of mild to moderate pain and has become so standardized in pain management that it is almost always available as a PRN (as needed) medication in a patient's medication list. However, it is often left unused and ignored. It is more often used for the management of a low-grade temperature (99F or above) or a fever (102F and above) for its antipyretic properties. One reason it remains unused is because physicians usually prescribe stronger opioid pain medications such as morphine, dilaudid, vicodin or percocet, which can be more effective for pain management. However, these medications are not without their side-effects; among them severe sedation, dizziness, constipation, nausea and vomiting, and hypotension (low blood pressure). 

Tylenol in the intravenous form is a relatively new formula. The brand Ofirmev was released and approved by the FDA for the treatment of acute pain in 2010. Its use in the hospital setting has been found in almost all types of units, but is more prevalently used in post-operative and orthopedic units. Why is this? IV Tylenol offers many benefits that addresses the main safety concerns that we focus on during surgery. These are respiratory depression and sedation (because of the use of anaesthetics), bleeding (from the incisions) and uncontrolled pain. The use of IV tylenol in the post-operative setting has a better safety margin than both opioid/narcotic pain medications and NSAIDs (non-steroidal anti-inflammatory drugs). Opioids can further depress the already depressed respiratory drive, cause decreased peristalsis (intestinal contraction that moves food along the gastrointestinal tract) to a GI tract that has already been slowed by the manipulation during surgery, while NSAIDs increase the risk of bleeding. Oral tablets are also not used because post-operative patients are at increased risk for aspiration (having a foreign object go into the lungs) and decreased GI motility. The question now is whether IV tylenol can achieve the same pain management effectiveness which stronger opioid pain medication are able to do.

There have been a handful of large, double-blind, placebo-controlled, randomized studies done on the effectiveness of IV Tylenol--most of these done in the perioperative setting (total hip or knee arthroplasty, abdominal laparoscopic surgery, abdominal/pelvic surgery, tonsillectomy, molar extraction). Some of the studies used made available to the patients the option of a "rescue" opioid pain medication dose to ensure that pain was still being under control. They showed that those who used IV Tylenol before surgery and after surgery required fewer doses of opioid pain doses than those  which did not have IV tylenol in the pain management plan. The IV Tylenol group also had statistically greater pain relief and better patient satisfaction compared with placebo groups.

IV tylenol is also more effective than oral or rectal tylenol because it takes effect quicker (peak concentrations in the body after the 15 minute IV infusion) and its bioavailability remains constant among variable subjects. Pain relief from oral or rectal tylenol is often variable among different subjects and its effects are not as rapid as the IV form. It is also much easier to transition from IV tylenol to liquid tylenol for use in the home than it is to transition from IV Dilaudid or IV Morphine to Vicodin or Percocet tablets. 

IV Tylenol has been used in same-day surgery settings where faster patient recovery times are the goal. The less the patient is sedated from narcotic pain medications, the faster they can go home. IV Tylenol is also used often as a part of a multi-modal pain management plan, where different types and strengths of pain medication are used and timed in such a way as to ensure pain control and decrease adverse side effects by lessening the doses used on each type of pain medication (for example, instead of monotherapy with Dilaudid 1, 2, and 3 mg for mild, moderate or severe pain; IV Tylenol 1000 mg every six hours will be scheduled along with oxycontin continuous release 30 mg twice a day, with Dilaudid 1 mg every three hours as needed for breakthrough pain). Multimodal pain management is the most effective way to achieve constant pain control and pre-emptive analgesia (treating pain before it starts to increase to intolerable levels). 

Whenever pain management is consulted for a patient whose pain control is not the most effective, they almost always have IV Tylenol on board the patient's schedule. This gives me the impression that general medical physicians or hospitalists are not as aware or up to date on the benefits or use of IV tylenol as pain management physicians are. More recently, I have seen IV Tylenol prescribed as a PRN for pain once for a patient, and I have never seen that done before. It can also be beneficial in the ER setting for rapid reduction of fevers. It would be interesting if instead of the Tylenol 650 mg oral standard that is almost always seen in every patient's medication list as a PRN for fever or mild/moderate pain, we start seeing IV Tylenol 1000 mg instead. However, before that happens I think more research needs to be done in its use, effectiveness and safety profile in the acute medical/surgical setting or even in oncology units, where uncontrollable cancer pain and nausea/vomiting can be the most devastating for patients.

References

Pasero, C. (2012). The Role of Intravenous Acetaminophen in Acute Pain Management: A Case-Illustrated Review. Pain Management Nursing, 13 (2), 107-124.

Kwiatkowski, J., Walker, P., & Arbor, A. (2013). Intravenous Acetaminophen in the Emergency Department. Journal of Emergency Nursing, 39 (1), 92-96.