Verticine is a steroidal alkaloid compound extracted from the Fritillaria species of medicinal plants. Verticine was not only able to block the Nav1.7 ion channel but also preferably inhibited the Kv1.3 ion channel. It inhibits the production of inflammatory cytokines induced by LPS through blocking MAPKs and NF-κB signaling pathways. Verticine inhibited the hERG peak tail currents in a concentration dependent manner. Verticine exhibits anti-inflammatory, antitussive, antihypertensive and pain suppression properties.

JNJ-17203212 is an TRPV1 receptor antagonist. The drug exerts potent antinociceptive and antitussive actions. JNJ-17203212 is developing by Johnson & Johnson for the treatment of pain and cough. No development reported.

Narceine methyl ester and narceine are potent alkaloids which were isolated from Corydalis longipes were found effective in vitro at very low concentration, i.e., 100~500 ppm against spore germination of some test plant pathogenic fungi (Alternaria solani, A. tagetica, Cercospora abelmoschi, Curvularia maculans, Erysiphe cichoracearum, E. pisi, Fusarium udum, Helminthosporium oryzae, H. penniseti, Ustilago cynodontis). George Bell Frankforter was the first person to isolate narceine (in 1893) during his Ph.D. research for August Hofmann at the University of Berlin. Narceine has a weak morphine-like action, but is not much used in medicine. It may be administered in a pill, as a mild hypnotic and to allay cough; it is less depressant than morphine and does not constipate. Ethylnarceine is a narcotic, analgesic, and antitussive.

PIPAZETHATE is a non-narcotic oral antitussive agent. It acts centrally on the medullary cough center and is used for the treatment of cough.

Pentoxyverine is a non-opioid antitussive used to prevent cough caused by common cold. It is used as an active ingredient of several oral over-the-counter cough suppressants alone or in combination with other medications, especially decongestants. Certuss is a combination of pentoxyverine and guaifenesin. Pentoxyverine is FDA pregnancy category C drug. Known as anticonvulsant, and spasmolytic agent.

Caramiphen is a muscarinic M1 acetylcholine receptor antagonist, which was used for the treatment of Parkinson Disease and cough, but then there using were discontinued. Caramiphen is also used in local anesthesia, and effect could be achieved through the suppression of voltage-gated Na⁺ currents.

Etafedrine, a sympathomimetic agent that acts on the sympathetic receptors of the bronchial tree relaxing spasm in a manner similar to that of ephedrine, is a bronchodilator and a selective β2-adrenoreceptor agonist. Contraction of the guinea pig tracheal chain by acetylcholine or histamine was antagonized by etafedrine with a higher potency then ephedrine but with a lower potency than epinephrine (adrenaline). Etafedrine did not increase heart rate or force of contraction in guinea pig atria. Unlike ephedrine and tyramine, etafedrine did not induce the release of noradrenaline as was demonstrated in vitro in the perfused rabbit heart and instead acted as a selective β2 adrenoreceptor agonist. Etafedrine also belongs to the family of medications called decongestants. It works by narrowing blood vessels in the nasal passages, helping to relieve nasal stuffiness. Etafedrine has been used in pharmaceutical compositions, such as NETHAPRIN Expectorant, Nethaprin Dospan and Dalmacol, useful in the treatment of asthma and other respiratory disorders including chronic bronchitis.

Ethylmorphine is a derivative of morphine with analgesic and antitussive effect. It acts by activating the opioid receptors and thus has a direct influence on the CNS system. Ethylmorphine was approved in Europe for the treatment of dry cough (Codethyline, Dionine).

Eucalyptol is a natural organic compound with fresh mint-like smell and a spicy, cooling taste. Eucalyptol comprises up to 90 percent of the essential oil of some species of the generic product Eucalyptus oil, hence the common name of the compound. It is also found in camphor laurel, bay leaves, tea tree, mugwort, sweet basil, wormwood, rosemary, common sage, Cannabis sativa and other aromatic plant foliage. Eucalyptol with a purity from 99.6 to 99.8 percent can be obtained in large quantities by fractional distillation of eucalyptus oil. Eucalyptol is an ingredient in many brands of mouthwash and cough suppressant, as well as an inactive ingredient in body powder. The typical concentrations of eucalyptol in cosmetic products have been reported to be 1.6% in perfume, 0.4% in soap, 0.1% in creams and lotions and 0.04% in detergents. Committee of Experts on Flavouring Substances of the Council of Europe (CEFS) proposed upper levels of 0.1 mg/kg in beverages and 5 mg/kg in food with the exception of 15 mg/kg in candy and confectionery and 50 mg/kg in alcoholic beverages. Eucalyptol controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition. Eucalyptol is an effective treatment for nonpurulent rhinosinusitis. Eucalyptol reduces inflammation and pain when applied topically.

Homatropine (used in a form of bromide or methylbromide salts) is an analogue of atropine, which acts as an antagonist of muscarinic receptors. Homatropine was approved for the treatment of cough in combination with hydrocodone bitartrate.