The question of whether a strong irritant like smelling salts can interrupt a seizure is common, often considered by bystanders or first responders. This idea stems from a misunderstanding of what causes a seizure and how ammonia inhalants work. Given the need for safe intervention during a neurological emergency, it is important to clarify the science behind this practice. Examining the physiological response to smelling salts reveals why they are effective for fainting but useless, and even hazardous, for a seizure.
The Chemical Mechanism of Smelling Salts
Smelling salts, often sold as ammonia inhalants, are chemical preparations designed to produce a startling, temporary physiological effect. These products typically consist of ammonium carbonate or a solution of diluted ammonia in water and alcohol. When a capsule is crushed or the solution is sniffed, ammonia gas (\(\text{NH}_3\)) is released directly into the nasal passages.
The ammonia gas is a powerful irritant that directly contacts the mucous membranes lining the nose and lungs. This irritation immediately triggers an involuntary protective response known as the inhalation reflex. The reflex causes an abrupt, deep gasp and speeds up the rate of breathing, which temporarily increases the flow of oxygen to the brain.
This irritant effect is why smelling salts have been traditionally used to revive a person who has fainted (syncope). Syncope is caused by a temporary decrease in blood flow to the brain, often involving an overactive vagal nerve that slows the heart. The sharp jolt from the ammonia irritant is intended to override this vagal response, essentially shocking the sympathetic nervous system back into action. This mechanism is purely a physical, reflexive stimulus and does not correct an underlying neurological malfunction.
Risks of Using Smelling Salts During a Seizure
The fundamental reason smelling salts cannot stop a seizure is that they address a circulatory issue (fainting) rather than an electrical one (seizure). A seizure is caused by a sudden, abnormal burst of electrical activity in the brain, a neurological event that ammonia gas is incapable of stopping. Attempting to use these irritants during a seizure introduces several serious, preventable risks.
One danger is the direct chemical hazard posed by the ammonia itself. The gas is corrosive, and holding the salts too close to the face can cause chemical burns to the nasal passages, eyes, and throat. Inhaling high concentrations of this toxic gas can also lead to severe airway constriction, coughing, and potential lung damage, especially if the individual’s breathing is already compromised during a seizure.
A second, equally serious risk is physical injury caused by the person’s reaction to the irritant. The intended physiological response is a sharp, involuntary withdrawal reflex, often resulting in a violent jerking of the head and neck. If the individual is mid-seizure, this sudden, forceful movement could cause or worsen a pre-existing spinal or neck injury.
Using smelling salts can create a false sense of effective intervention, which delays proper medical attention. The priority during a seizure is to protect the individual from injury and time the event, not to attempt to “wake them up.” Delaying the call for emergency services by trying an ineffective intervention can have severe consequences, particularly if the seizure lasts longer than five minutes.
Recommended First Aid for Seizures
The proper response to a person experiencing a seizure focuses entirely on keeping the individual safe and monitoring the event. The simple, evidence-based protocol is often summarized as “Time, Protect, Stay”. This approach prioritizes managing the risks of injury and complications until the seizure ends on its own.
The first action is to time the seizure immediately, noting precisely when the uncontrolled movements begin. If the seizure lasts longer than five minutes, emergency medical services must be called, as a prolonged seizure requires professional intervention.
Next, the focus shifts to protecting the person from injury by clearing the area of any hard, sharp, or dangerous objects. Placing something soft, such as a folded jacket or towel, underneath the person’s head will help cushion it from the floor. It is also important to loosen any tight clothing around their neck to aid breathing.
As soon as the convulsive movements stop, or if the person has food or fluid in their mouth, gently turn them onto their side into the recovery position. This action helps keep the airway clear and prevents any fluid from being inhaled into the lungs. Finally, stay with the person until they fully regain consciousness, speaking calmly and reassuringly while they recover.