Respirants

Respirants are substances historically described as irritants of the respiratory mucosa that provoke a reflex increase in breathing. In 19th- and early 20th-century pharmacology, the term covered volatile or pungent compounds used to restore or stimulate respiration in situations such as fainting, overdose, or during anesthesia when breathing was slowed or interrupted. In modern pharmacology, the term is largely obsolete, with agents more commonly categorized as respiratory stimulants, irritants, or inhalants rather than as “respirants.”

Common historical examples include smelling salts containing ammonia carbonate, and other volatile irritants such as camphor, menthol, and peppermint oils. Some alcohol-based inhalants and essential oils were also described as respirants. These agents typically act by irritating the nasal or airway mucosa and triggering the trigeminal nerve, leading to a reflex increase in ventilation; in some cases central nervous system stimulation contributes to the effect.

Safety and limitations are important considerations. The respiratory stimulation produced by irritants is highly variable between individuals and can cause adverse effects such as coughing, nasal or airway irritation, bronchospasm, and mucosal injury. They are not suitable for routine use or chronic treatment and can be dangerous for individuals with asthma, chronic obstructive pulmonary disease, heart disease, or during poisoning, pregnancy, or certain medical conditions.

Today, the term “respirant” is rarely used in clinical practice. When clinicians discuss augmentation of respiration, they refer to respiratory stimulants or supportive measures, rather than irritant inhalants. The concept remains primarily of historical interest in the study of respiration and pharmacology. See also respiratory stimulant, smelling salts, ammonia inhalants, inhalational irritants, cough reflex.