Racepinephrine or racemic epinephrine is a mixture of levo and dextro isomers of epinephrine act as a nonselective agonist at adrenergic receptors. It is a bronchodilator used in the temporary relief of mild symptoms of intermittent asthma including wheezing, shortness of breath. Inhaled racepinephrine became available in September 2012 as a nonprescription treatment for bronchospasm based on a 1986 US Food and Drug Administration rule. Besides, racemic epinephrine relieves respiratory distress in hospitalized infants with bronchiolitis and is safe but does not abbreviate hospital stay. Morbidity associated with bronchiolitis as identified by parents persists for at least one week after hospital discharge in most infants.

Clotrimazole is an anti-fungal medicine indicated for the treatment of vaginal yeast infections and tinea. It can be used either in combination with other drugs (betamethasone dipropionate) or alone, in form of topical or vaginal cream. The drug exerts its action by inhibiting lanosterol demethylase thereby affecting the growth of fungi.

Racephedrine in combination with theophylline, phenobarbital was used to treat bronchial asthma. However, its application was substituted more effective agent. In addition, FDA has reviewed the final monograph for over-the-counter bronchodilator drug products to add additional warnings and to revise the indications in the labeling of products containing racephedrine hydrochloride.

Pseudoephedrine is a sympathomimetic drug. Pseudoephedrine acts as an adrenomimetic and inhibitor of monoamine transporters. Ephedra sinica, a species of ephedra (ma huang), contains ephedrine and pseudoephedrine. Ephedra has been found to stimulate the nervous system, increase airflow into the lungs and constrict blood vessels. In combination with caffeine, ephedra appears to cause weight loss. Pseudoephedrine is a decongestant that shrinks blood vessels in the nasal passages. Pseudoephedrine is used to relieve nasal or sinus congestion caused by the common cold, sinusitis, and hay fever and other respiratory allergies.

Chlophedianol (Clofedanol) is a centrally-acting cough suppressant, although the mechanism of action is not known. It is available in Canada under the trade name Ulone. It is not available in the United States. Chlophedianol (Clofedanol) suppresses the cough reflex by a direct effect on the cough center in the medulla of the brain. It also has local anesthetic and antihistamine properties, and may have anticholinergic effects at high doses.

Dextromethorphan is a non-narcotic morphine derivative widely used as an antitussive for almost 40 years. It has attracted attention due to its anticonvulsant and neuroprotective properties. It is a cough suppressant in many over-the-counter cold and cough medicines. In 2010, the FDA approved the combination product dextromethorphan/quinidine for the treatment of pseudobulbar affect. Dextromethorphan suppresses the cough reflex by a direct action on the cough center in the medulla of the brain. Dextromethorphan shows high-affinity binding to several regions of the brain, including the medullary cough center. This compound is an NMDA receptor antagonist and acts as a non-competitive channel blocker. It is one of the widely used antitussives and is used to study the involvement of glutamate receptors in neurotoxicity. Dextromethorphan (DM) is a sigma-1 receptor agonist and an uncompetitive NMDA receptor antagonist. The mechanism by which dextromethorphan exerts therapeutic effects in patients with pseudobulbar affect is unknown. Dextromethorphan should not be taken with monoamine oxidase inhibitors due to the potential for serotonin syndrome. Dextromethorphan is extensively metabolized by CYP2D6 to dextrorphan, which is rapidly glucuronidated and unable to cross the blood-brain barrier.

Meclizine, a piperazine-derivative H1-receptor antagonist similar to buclizine, cyclizine, and hydroxyzine, is used as an antivertigo/antiemetic agent. Meclizine is used in the management of nausea, vomiting, and dizziness associated with motion sickness and vertigo in diseases affecting the vestibular apparatus. Along with its actions as an antagonist at H1-receptors, meclizine also possesses anticholinergic, central nervous system depressant, and local anesthetic effects. Meclizine depresses labyrinth excitability and vestibular stimulation and may affect the medullary chemoreceptor trigger zone. It is sold under the brand names Bonine, Bonamine, Antivert, Postafen, Sea Legs, and Dramamine II.

Discovered as natural products from actinomycetes soil bacteria, the tetracyclines were first reported in the scientific literature in 1948. They were noted for their broad spectrum antibacterial activity and were commercialized with clinical success beginning in the late 1940s to the early 1950s. By catalytic hydrogenation of Aureomycin, using palladium metal and hydrogen, the C7 deschloro derivative was synthesized, producing a compound of higher potency, a better solubility profile, and favorable pharmacological activity; it was subsequently named tetracycline. Tetracyclines are primarily bacteriostatic and exert their antimicrobial effect by the inhibition of protein synthesis by binding to the 30S ribosomal subunit. Tetracycline is active against a broad range of gram-negative and gram-positive organisms. Tetracycline is indicated in the treatment of infections caused by susceptible strains. To reduce the development of drug-resistant bacteria and maintain the effectiveness of tetracycline hydrochloride and other antibacterial drugs, tetracycline hydrochloride should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

Oxytetracycline, a tetracycline analog isolated from the actinomycete streptomyces rimosus, was the second of the broad-spectrum tetracycline group of antibiotics to be discovered The drug is used for the prophylaxis and local treatment of superficial ocular infections due to oxytetracycline- and polymyxin-sensitive organisms for animal use only. These infections include the following: Ocular infections due to streptococci, rickettsiae E. coli, and A. aerogenes (such as conjunctivitis, keratitis, pinkeye, corneal ulcer, and blepharitis in dogs); ocular infections due to secondary bacterial complications associated with distemper in dogs; and ocular infections due to bacterial inflammatory conditions which may occur secondary to other diseases in dogs. Allergic reactions may occasionally occur. Treatment should be discontinued if reactions are severe. If new infections due to nonsensitive bacteria or fungi appear during therapy, appropriate measures should be taken. Oxytetracycline inhibits cell growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. The binding is reversible in nature. Oxytetracycline is lipophilic and can easily pass through the cell membrane or passively diffuses through porin channels in the bacterial membrane.

Chlorpheniramine is an antihistamine. Chlorpheniramine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Chlorpheniramine is used for relieving symptoms of sinus congestion, sinus pressure, runny nose, watery eyes, itching of the nose and throat, and sneezing due to upper respiratory infections (eg, colds), allergies, and hay fever. In addition to being a histamine H1 receptor (HRH1) antagonist, chlorphenamine has been shown to work as a serotonin-norepinephrine reuptake inhibitor or SNRI.