title: Intravenous versus Oral Acetaminophen for Pain: Systematic Review of Current Evidence to Support Clinical Decision-Making.
abstract: BACKGROUND
  Intravenous (IV) acetaminophen is increasingly used around the world for pain control for a variety of indications. However, it is unclear whether IV administration offers advantages over oral administration.
  
  
  OBJECTIVE
  To identify, summarize, and critically evaluate the literature comparing analgesic efficacy, safety, and pharmacokinetics for IV and oral dosage forms of acetaminophen.
  
  
  METHODS
  A literature search of the PubMed, Embase, and International Pharmaceutical Abstracts databases was supplemented with keyword searches of Science Direct, Wiley Library Online, and Springer Link databases for the period 1948 to November 2014. The reference lists of identified studies were searched manually.
  
  
  METHODS
  Randomized controlled trials comparing IV and oral dosage forms of acetaminophen were included if they assessed an efficacy, safety, or pharmacokinetic outcome. For each study, 2 investigators independently extracted data (study design, population, interventions, follow-up, efficacy outcomes, safety outcomes, pharmacokinetic outcomes, and any other pertinent information) and completed risk-of-bias assessments.
  
  
  RESULTS
  Six randomized clinical trials were included. Three of the studies reported outcomes pertaining to efficacy, 4 to safety, and 4 to pharmacokinetics. No clinically significant differences in efficacy were found between the 2 dosage forms. Safety outcomes were not reported consistently enough to allow adequate assessment. No evidence was found to suggest that increased bioavailability of the IV formulation enhances efficacy outcomes. For studies reporting clinical outcomes, the results of risk-of-bias assessments were largely unclear.
  
  
  CONCLUSIONS
  For patients who can take an oral dosage form, no clear indication exists for preferential prescribing of IV acetaminophen. Decision-making must take into account the known adverse effects of each dosage form and other considerations such as convenience and cost. Future studies should assess multiple-dose regimens over longer periods for patients with common pain indications such as cancer, trauma, and surgery.
authors.affiliation: BSc(Pharm), PharmD, is a Clinical Pharmacist at the National Center for Cancer Care and Research, Doha, Qatar.
authors.forename: Farah
authors.initials: F
authors.lastname: Jibril
authors.affiliation: Sherif Sharaby, BSc(Pharm), is a Pharmacist with the San Joaquin Valley Rehabilitation Hospital, Fresno, California.
authors.forename: Sherif
authors.initials: S
authors.lastname: Sharaby
authors.affiliation: BSc(Pharm), PhD, is an Assistant Professor with the College of Pharmacy, Qatar University, Doha, Qatar.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mohamed
authors.affiliation: BSP, ACPR, PharmD, is an Assistant Professor - Clinical Pharmacy and Practice, College of Pharmacy, Qatar University, Doha, Qatar.
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Wilby
keywords: acetaminophen; analgesia; intravenous; pain; paracetamol