Efﬁcacy of Superactivated Charcoal
Administered Late (3 Hours) After
RENEE L. SATO, JEFFREY J. WONG, SHAWN M. SUMIDA, RICHARD Y. MARN, MD,
NATHAN R. ENOKI, MD, AND LOREN G. YAMAMOTO, MD, MPH
The purpose of this study was to investigate the effect of superactivated
charcoal (SAC) given late after a drug overdose. Acetaminophen was
chosen as our overdose drug because it has relatively few side effects,
serum levels are easily attainable and measurable, and it is generally a
common drug overdose. Forty-six healthy adult volunteers participated
in this randomized, controlled study. Acetaminophen was administered
the morning after an overnight fast. Thirteen participants received 2000
mg acetaminophen and the remaining 33 received 3000 mg. After 3
hours, half of the participants (22 of 46) received 75 g of SAC (Requa,
Greenwich, CT) orally as a slurry in 8 oz of apple juice. Serum acetamin-
ophen levels were measured at 4 and 7 hours after the initial acetamin-
ophen administration. There were signiﬁcantly lower uncorrected and
corrected acetaminophen levels in the SAC group compared with the
control group at both 4 and 7 hours after ingesting acetaminophen. This
randomized human experimental design trial demonstrates some detox-
iﬁcation beneﬁt in administering superactivated charcoal 3 hours after
an overdose. (Am J Emerg Med 2003;21:189-191. © 2003 Elsevier Inc. All
Activated charcoal (AC) is commonly used as a detoxi-
ﬁcation agent in suspected drug overdoses. It is efﬁcacious
if given early.
However, patients who have overdosed on
a drug tend to present to the ED several hours after the
overdose. There is no clear consensus on the efﬁcacy of late
AC administration in the treatment of drug overdoses. The
1998 position statement of the American Academy of Clin-
ical Toxicology, European Association of Poisons Centres,
and Clinical Toxicologists regarding the use of activated
charcoal states that “there are insufﬁcient data to support or
exclude its use after 1 hour of ingestion. There is no evi-
dence that the administration of charcoal improves clinical
The purpose of this study was to investigate the
detoxiﬁcation efﬁcacy of superactivated (high surface area)
charcoal given late in a drug overdose.
This is a randomized, unblinded human experimental design
trial. Acetaminophen was chosen as our overdose study drug
because it has relatively few side effects, serum levels are
easily attainable and measurable, and it is a common drug
overdose. Healthy adult study subjects were recruited and paid
$50 for study participation. Subjects were randomized by a
coin ﬂip to charcoal or control. Although the study investiga-
tors were unblinded, the phlebotomy and laboratory staff who
reported the acetaminophen levels were blinded to the sub-
jects’ randomization status. A health screening questionnaire
was used to exclude study subjects with (1) allergy to acet-
aminophen, (2) hepatic or renal disease, (3) heavy alcohol use,
(4) chronic gastrointestinal disease, or (5) use of any medica-
tion within 24 hours of the study. The study protocol recom-
mended a screening serum alanine transaminase (ALT) assay
before the study to screen for occult liver disease.
Written informed consent was obtained and after this,
acetaminophen (Tylenol, McNeil-PPC, Fort Washington,
PA) was administered as a single dose the morning after an
overnight fast. After 3 hours, those subjects randomized to
charcoal received 75 g superactivated charcoal (SAC, sur-
face area: 2,000 m
/g; Requa, Greenwich, CT) orally as a
slurry in 240 mL of apple juice. The length of time it took
to ingest the SAC was recorded. Serum acetaminophen
levels were measured at 4 and 7 hours after the initial
acetaminophen dose. Within a week after these events, the
participants were surveyed for adverse effects.
Results were coded into a spreadsheet and analyzed using
SAS computerized statistical software (SAS, Cary, NC).
This study was approved by the Institutional Review Board
at Kapiolani Medical Center for Women and Children.
Forty-eight participants were randomized. Two partici-
pants in the activated charcoal group could not complete
charcoal ingestion and were excluded from analyses. Thus,
46 participants took either a 2-g (ﬁrst 13 subjects) or 3-g
(remaining 33) dose of acetaminophen. The ﬁrst 13 subjects
were given 2-g acetaminophen doses under the initial pro-
tocol proposal, but we found that the 4- and 7-hour levels
were too low to be potentially impacted by any detoxiﬁca-
From the Department of Pediatrics, University of Hawaii, John A.
Burns School of Medicine, Clinical Research Center, Kapiolani Med-
ical Center for Women and Children, Honolulu, HI.
Manuscript received February 1, 2002, accepted June 13, 2002.
Supported by a Research Centers in Minority Institutions award,
P20 RR11091, from the National Center for Research Resources,
National Institutes of Health. Its contents are solely the responsibility
of the authors and do not necessarily represent the ofﬁcial views of
the National Center for Research Resources, National Institutes of
An abstract of this study has been presented at the Scientiﬁc
Research Forum of the American College of Emergency Physicians
Annual Meeting, Chicago, IL, October 2001, and the National Con-
ference and Exhibition of the American Academy of Pediatrics, San
Francisco, CA, October 2001.
Address reprint requests to Loren G. Yamamoto, MD, MPH, MBA,
Professor of Pediatrics, University of Hawaii, John A. Burns School
of Medicine, 1319 Punahou Street, #733, Honolulu, HI 96826.
Key Words: Activated charcoal, detoxiﬁcation, toxicology, drug
overdose, acetaminophen overdose.
© 2003 Elsevier Inc. All rights reserved.