Page 11 - Journal of Special Operations Medicine - Summer 2015

Cinnarizine for Sea Sickness

During a Remote Pacific Ocean Rescue Mission

Regan F. Lyon, MD; Stephen C. Rush, MD; J. Thomas Roland Jr, MD;
Daniel Jethanamest, MD; Christopher P. Schwan, MD; Chetan U. Kharod, MD

ABSTRACT
Motion sickness can be a limiting factor for sea and air response to real or perceived unusual motion commonly
missions. We report the experience of a Pararescue (PJ) report nausea, vomiting, apathy, drowsiness, lethargy,
team on a Pacific Ocean rescue mission in which motion difficulty concentrating, pallor, and dizziness. Any one
1
sickness was prevalent. Cinnarizine, an antagonist of of these symptoms can be detrimental to rescue missions
H1-histamine receptors, was used to treat affected PJs. both in peacetime and wartime.
We also report findings of a survey of PJs regarding mo-
tion sickness. A family of four on a disabled sailboat 900 A common hypothesis for the phenomenon of motion
miles off the coast of Mexico sent out a distress call be- sickness is that it is a response to conflicting input from
cause their 1-year-old daughter became severely ill with various sensory systems: vestibular, visual, and proprio-
2
fever and diarrhea. Four PJs were deployed on a C-130, ceptor. When moving in aircraft or over sea with a lim-
performed a free-fall parachute insertion into the ocean, ited or impaired view of the external environment, the
and boarded the sailboat. All four PJs experienced onset signals of acceleration and motion from the semicircular
of motion sickness at some point during the early part canals and otolithic organs of the vestibular system will
of the mission and symptoms persisted through the first be mismatched with the visual perception of a lack of
24 hours. Three PJs experienced ongoing nausea, vomit- movement. The brain sees this mismatch of information
ing, dizziness, and sensory imbalances. The captain of as a warning sign and triggers nausea, vomiting, and
3
the sailboat offered the three sick PJs approximately the other symptoms of the condition. Various hypoth-
18mg of cinnarizine two or three times a day with re- eses for the biologic role of motion sickness include an
lief of symptoms and improvement on operational ef- evolved response to potential neurotoxins, aberrant ves-
fectiveness. A new, anonymous, voluntary survey of Air tibular reflexes, or a response to avoid physical disori-
National Guard PJs and combat rescue officers revealed entation. The neural mechanism of motion sickness
2–4
that 78.4% of Operators have experienced motion sick- is poorly understood, but may be related to brainstem
ness at sea. We discuss the current theories on motion pathways and is more prevalent in patients with vestibu-
sickness, the effect of motion sickness on operational lar disturbances or migraines. 5–7
effectiveness, and research on treatment of motion sick-
ness, including the medication cinnarizine. Treatment for motion sickness includes both nonphar-
maceutical and pharmaceutical interventions. Nonphar-
Keywords: motion sickness; cinnarizine; military operations; maceutical interventions include measures that assist the
military medicine; sea sickness; medication, motion sickness; individual adapt to the multitude of changing sensory
Pararescue inputs. Fixating on the horizon and/or moving into an
open area where the surroundings can be easily seen are
recommended. Affected individuals should also avoid
reading or frequent changes in visual fixation. 2
Introduction
Motion sickness is a common condition experienced by Medications commonly used for motion sickness fall
people in unnatural environments, including air, sea, into two main categories: antihistamines and anticholin-
and space. This condition is of importance to US Air ergics. Antihistamines, such as dimenhydrinate, mecli-
1
Force (USAF) Pararescuemen (PJs), since most of their zine, and promethazine, block the H1 receptors located
2
missions include at least one of these environments dur- in the vestibular nuclei. Common side effects of these
ing an operation. Individuals affected by this physiologic medications are drowsiness and cognitive impairment,

1