Benzonatate is an antitussive that is FDA approved for the symptomatic relief of cough. It acts peripherally by anesthetizing the stretch receptors located in the respiratory passages, lungs, and pleura by dampening their activity and thereby reducing the cough reflex at its source. Common adverse reactions include nausea, oral hypoesthesia, throat symptom, numbness, dizziness, headache, sedation, somnolence. Benzonatate is chemically related to anesthetic agents of the para-amino-benzoic acid class (e.g. procaine; tetracaine) and has been associated with adverse CNS effects possibly related to a prior sensitivity to related agents or interaction with concomitant medication.

Cloperastine (INN) or cloperastin is an antitussive and antihistamine that is marketed as a cough suppressant in Japan, Hong Kong, and in some European countries. It was first introduced in 1972 in Japan, and then in Italy in 1981. The precise mechanism of action of cloperastine is not fully clear, but several different biological activities have been identified for the drug, of which include: ligand of the gamma1 receptor (Ki = 20 nM) (likely an agonist), GIRK channel blocker (described as "potent"), antihistamine (Ki = 3.8 nM for the H1 receptor), and anticholinergic. Cloperastine possesses dual activity. It also acts as a mild bronchorelaxant and has antihistaminic activity, without acting on the central nervous system or the respiratory center.

Tipepidine (INN) also known as tipepidine hibenzate (JAN), is a synthetic, non-opioid antitussive and expectorant of the thiambutene class. The drug was discovered in the 1950s, and was developed in Japan in 1959. It is used as the hibenzate and citrate salts. The safety of tipepidine in children and adults has already been established. It is reported that tipepidine inhibits G-protein-coupled inwardly rectifying potassium (GIRK)-channel currents. The inhibition of GIRK channels by tipepidine is expected to modulate the level of monoamines in the brain. Tipepidine can improve attention deficit/hyperactivity disorder (ADHD) symptoms by modulating monoaminergic neurotransmission through the inhibition of GIRK channels. Tipepidine also is being investigated in depression, obsessive-compulsive disorder, and attention-deficit hyperactivity disorder (ADHD). As it acts on the central nervous system, overdose can cause altered mental status and other neurological symptoms; however, there have been few reports of tipepidine intoxication, including six cases in children and no cases in adults.

Cloperastine (INN) or cloperastin is an antitussive and antihistamine that is marketed as a cough suppressant in Japan, Hong Kong, and in some European countries. It was first introduced in 1972 in Japan, and then in Italy in 1981. The precise mechanism of action of cloperastine is not fully clear, but several different biological activities have been identified for the drug, of which include: ligand of the gamma1 receptor (Ki = 20 nM) (likely an agonist), GIRK channel blocker (described as "potent"), antihistamine (Ki = 3.8 nM for the H1 receptor), and anticholinergic. Cloperastine possesses dual activity. It also acts as a mild bronchorelaxant and has antihistaminic activity, without acting on the central nervous system or the respiratory center.

Cloperastine (INN) or cloperastin is an antitussive and antihistamine that is marketed as a cough suppressant in Japan, Hong Kong, and in some European countries. It was first introduced in 1972 in Japan, and then in Italy in 1981. The precise mechanism of action of cloperastine is not fully clear, but several different biological activities have been identified for the drug, of which include: ligand of the gamma1 receptor (Ki = 20 nM) (likely an agonist), GIRK channel blocker (described as "potent"), antihistamine (Ki = 3.8 nM for the H1 receptor), and anticholinergic. Cloperastine possesses dual activity. It also acts as a mild bronchorelaxant and has antihistaminic activity, without acting on the central nervous system or the respiratory center.

Tipepidine (INN) also known as tipepidine hibenzate (JAN), is a synthetic, non-opioid antitussive and expectorant of the thiambutene class. The drug was discovered in the 1950s, and was developed in Japan in 1959. It is used as the hibenzate and citrate salts. The safety of tipepidine in children and adults has already been established. It is reported that tipepidine inhibits G-protein-coupled inwardly rectifying potassium (GIRK)-channel currents. The inhibition of GIRK channels by tipepidine is expected to modulate the level of monoamines in the brain. Tipepidine can improve attention deficit/hyperactivity disorder (ADHD) symptoms by modulating monoaminergic neurotransmission through the inhibition of GIRK channels. Tipepidine also is being investigated in depression, obsessive-compulsive disorder, and attention-deficit hyperactivity disorder (ADHD). As it acts on the central nervous system, overdose can cause altered mental status and other neurological symptoms; however, there have been few reports of tipepidine intoxication, including six cases in children and no cases in adults.