contraindications

Asthma. Although ketamine has been used as therapy for
active asthma,38-41 there is insufficient experience to support its
safety in this setting, and indeed asthma is a known
laryngospasm risk factor in pediatric inhalational anesthesia.33
There is no evidence to support quiescent asthma as a
contraindication. Ketamine is not contraindicated for rapid
sequence intubation in severe asthma, assuming that a
neuromuscular blocker is coadministered to eliminate the
possibility of laryngospasm.
Laryngospasm. Given that several of the relative
contraindications described above are based on an enhanced risk
of laryngospasm, it is expected that emergency physicians will
appraise this risk according to their relative comfort with
managing this adverse event. Ketamine-associated laryngospasm
is relatively uncommon (0.3% incidence in children in the large
meta-analysis)2 and essentially always has been transient and
responded quickly to assisted ventilation and oxygen. There are
2 reported occurrences of protracted and recurrent ED
laryngospasm, including 1 child who required intubation42;
however, neither child experienced hypoxia or any
complications.

Cardiac disease. According to inconclusive evidence, it
has been widely recommended that ketamine be avoided in
children or adults with known or possible coronary artery
disease, congestive heart failure, or hypertension.12,15,16,43
Ketamine inhibits the reuptake of catecholamines, and the
resulting sympathomimetic effect produces mild to moderate
increases in blood pressure, pulse rate, cardiac output, and
myocardial oxygen consumption. Evidence is inconclusive
about whether the increased coronary perfusion associated
with this hyperdynamic state parallels increases in oxygen
demand.4,12,16,44,45
The literature is silent about a maximum age for ketamine.
Although this drug can precipitate myocardial ischemia in the
elderly,46 no such occurrences have been reported in the ED
setting.24-28 Although millions of older adults in the developing
world have safely received ketamine during the past 40 years

(where this drug continues to be widely administered in
operating theaters as an inexpensive and simple alternative to
inhalational anesthesia4,31,35,36), coronary artery disease is
uncommon in such settings. Although ketamine has been used
for cardiac surgery in the elderly, this has been in conjunction
with cardiodepressant agents that would be expected to mitigate
its effects.24,26 Emergency physicians must weigh the risks and
benefits of ketamine in older adults who may have unrecognized
coronary artery disease.
The literature is silent about any association between
ketamine and over-the-counter sympathomimetics (eg,
pseudoephedrine) or prescription stimulants (eg,
methylphenidate), and so these medications do not represent a
contraindication.