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Concept: Cough medicine


Dextromethorphan (3-methoxy-N-methylmorphinan), also known as “DXM” and “the poor man’s PCP,” is a synthetically produced drug that is available in more than 140 over-the-counter cough and cold preparations. Dextromethorphan (DXM) has overtaken codeine as the most widely used cough suppressant due to its availability, efficacy, and safety profile at directed doses. However, DXM is subject to abuse. When consumed at inappropriately high doses (over 1500 mg/day), DXM can induce a state of psychosis characterized by Phencyclidine (PCP)-like psychological symptoms, including delusions, hallucinations, and paranoia. We report a noteworthy case of severe dextromethorphan use disorder with dextromethorphan-induced psychotic disorder in a 40-year-old Caucasian female, whose symptoms remitted only following treatment with a combination of an antipsychotic and mood stabilizer. While some states have begun to limit the quantity of DXM sold or restrict sales to individuals over 18-years of age, there is currently no federal ban or restriction on DXM. Abuse of DXM, a readily available and typically inexpensive agent that is not detected on a standard urine drug screen, may be an under-recognized cause of substance-induced psychosis. It is imperative that clinicians are aware of the potential psychiatric sequelae of recreational DXM use.

Concepts: Cough, Schizophrenia, Psychosis, Bipolar disorder, Psychiatry, Common cold, Codeine, Cough medicine


Background: Currently available over-the-counter cough remedies historically have been criticized for lack of scientific evidence supporting their efficacy. Although the first-generation antihistamine diphenhydramine is classified as an antitussive by the United States Food and Drug Administration, to the authors' knowledge it has never been shown to inhibit cough reflex sensitivity in subjects with pathological cough. Objective: To evaluate the effect of diphenhydramine on cough reflex sensitivity. Setting: Montefiore Medical Center, an academic medical center in New York City. Methods: Twenty two subjects with acute viral upper respiratory tract infection (common cold) underwent cough reflex sensitivity measurement employing capsaicin challenge on 3 separate days, 2 h after ingesting single doses of study drug (to coincide with peak blood concentrations), administered in randomized, double-blind manner: a multicomponent syrup containing diphenhydramine (25 mg), phenylephrine (10 mg), in a natural cocoa formulation; dextromethorphan (30 mg) syrup; and, placebo syrup. The standard endpoint of cough challenge was used: concentration of capsaicin inducing ≥5 coughs (C5). Main outcome measure: Effect on cough reflex sensitivity (C5). Results: A significant difference (p = 0.0024) was established among groups, with pairwise analysis revealing a significant increase in mean log C5 (0.4 ± 0.55 (SD); p < 0.01) for the diphenhydramine-containing medication versus placebo, but not for dextromethorphan versus placebo. Conclusions: Our results provide the initial evidence of the ability of diphenhydramine to inhibit cough reflex sensitivity in subjects with acute pathological cough. Timing of cough reflex sensitivity measurement may not have allowed demonstration of maximal antitussive effect of dextromethorphan.

Concepts: Cough, Respiratory system, Upper respiratory tract, Upper respiratory tract infection, Lower respiratory tract, Common cold, Codeine, Cough medicine


Codeine-containing cough syrups have become one of the most popular drugs of abuse in young people in the world. Chronic codeine-containing cough syrup abuse is related to impairments in a broad range of cognitive functions. However, the potential brain white matter impairment caused by chronic codeine-containing cough syrup abuse has not been reported previously. Our aim was to investigate abnormalities in the microstructure of brain white matter in chronic users of codeine-containing syrups and to determine whether these WM abnormalities are related to the duration of the use these syrups and clinical impulsivity.

Concepts: Psychology, Matter, Cognition, Mind, Common cold, Recreational drug use, Cough medicine, Purple drank


Dextromethorphan is a safe, effective cough suppressant, available without a prescription in the United States since 1958. Due to a perceived prevalence of abuse of dextromethorphan by teens, in 2007 the Drug Enforcement Administration requested the Food and Drug Administration evaluate whether dextromethorphan should be recommended for scheduling under the Controlled Substances Act. The Food and Drug Administration held an Advisory Committee meeting in 2010 to provide a scientific and medical evaluation of dextromethorphan and its abuse potential.

Concepts: Cough, United States, Controlled Substances Act, Food and Drug Administration, Latin, Codeine, Drug Enforcement Administration, Cough medicine


There is little evidence that the decongestant, antihistamine, or cough suppressant medications commonly used to treat cold symptoms in preschool children are effective. One option for treating cold symptoms in young children is with homeopathy. This study was conducted to determine if a homeopathic syrup was effective in treating cold symptoms in preschool children.

Concepts: Pharmacology, Cough, Randomized controlled trial, Placebo, Alternative medicine, Common cold, Homeopathy, Cough medicine


Unexplained chronic cough (UCC) affects millions of patients worldwide. New therapeutic approaches to this condition are urgently needed, since current treatment options provide only symptomatic relief. Cough reflex hypersensitivity has been shown to play an important role in the pathogenesis of UCC. The transient receptor potential vanilloid type 1 (TRPV1) is present on peripheral terminals of airway sensory nerves and modulation of its activity represents a potential target for the pharmacological treatment of UCC. The aim of this study was to explore the efficacy and the possible mechanism of SB705498, a TRPV1 antagonist, for cough in a capsaicin-induced cough animal model (i.e. guinea pigs). Induction of cough by capsaicin was successfully implemented in the guinea pigs, and the animals that met the inclusion criteria were randomly divided into four treatment groups: (1) Saline inhalation group (NSInh group, N = 10, negative control group), (2) Codeine phosphate intraperitoneal injection group (CPInp group, N = 10, positive control group), (3) SB705498 inhalation group (SBInh group, N = 10), (4) SB705498 intragastric administration group (SBIng group, N = 10). After treatment with above compounds, the capsaicin-induced cough experiment was performed again. The cough numbers and the cough incubation periods were recorded to evaluate the antitussive effect of SB705498. Enzyme-linked immunosorbent assay (ELISA) testing and Immunohistochemistry (IHC) staining for substance P (SP), calcitonin gene related peptide (CGRP) and neurokinin A (NKA) expression in lung and brain tissues were performed as an indication of neurogenic inflammation. Hematoxylin-Eosin (H&E) staining was used to observe the pathology morphology of lung and brain tissues. When the CPInp, SBInh and SBIng groups were compared to the NSInh group, the cough numbers were significantly reduced (p < .001), while the cough incubation periods were significantly prolonged (P < .001). In addition, the expression of SP, CGRP and NKA in lung and brain tissue was reduced (P < .05). None of the animals in the four groups exhibited lung and brain parenchymal inflammation. The results from this study showed that SB705498 had a significant antitussive effect, could reduce the neurogenic inflammation by reducing the expression of SP, CGRP and NKA in a capsaicin-induced cough model of guinea pigs. The results further indicated that TRPV1 played an important role in UCC and SB705498 might be a promising therapeutic agent for UCC.

Concepts: Scientific control, Nervous system, Cough, Human brain, ELISA, Eva Engvall, Codeine, Cough medicine


Acute cough associated with the common cold (CACC) causes significant impairment in quality of life. Effective treatment approaches are needed for CACC. We conducted a systematic review on the management of CACC to update the recommendations and suggestions of the CHEST 2006 guideline on this topic.

Concepts: Asthma, Cough, Common cold, Dextromethorphan, Cough medicine


The modulation of cough by microinjections of codeine in 3 medullary regions, the solitary tract nucleus rostral to the obex (rNTS), caudal to the obex (cNTS) and the lateral tegmental field (FTL) was studied. Experiments were performed on 27 anesthetized spontaneously breathing cats. Electromyograms (EMG) were recorded from the sternal diaphragm and expiratory muscles (transversus abdominis and/or obliquus externus; ABD). Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airways. Bilateral microinjections of codeine (3.3 or 33mM, 54±16nl per injection) in the cNTS had no effect on cough, while those in the rNTS and in the FTL reduced coughing. Bilateral microinjections into the rNTS (3.3mM codeine, 34±1 nl per injection) reduced the number of cough responses by 24% (P<0.05), amplitudes of diaphragm EMG by 19% (P<0.01), of ABD EMG by 49% (P<0.001) and of expiratory esophageal pressure by 56% (P<0.001). Bilateral microinjections into the FTL (33mM codeine, 33±3 nl per injection) induced reductions in cough expiratory as well as inspiratory EMG amplitudes (ABD by 60% and diaphragm by 34%; P<0.01) and esophageal pressure amplitudes (expiratory by 55% and inspiratory by 26%; P<0.001 and 0.01, respectively). Microinjections of vehicle did not significantly alter coughing. Breathing was not affected by microinjections of codeine. These results suggest that: 1) codeine acts within the rNTS and the FTL to reduce cough in the cat, 2) the neuronal circuits in these target areas have unequal sensitivity to codeine and/or they have differential effects on spatiotemporal control of cough, 3) the cNTS has a limited role in the cough suppression induced by codeine in cats.

Concepts: Neuroanatomy, Cough, Transversus abdominis muscle, Gastroesophageal reflux disease, Cat, Iliac crest, Codeine, Cough medicine


A 25-year-old college student with no medical history sought care at our hospital for a nonproductive cough, subjective fevers, myalgia, and malaise that he’d developed 10 days earlier. The day before his visit, he’d also developed scratchy red eyes and a sore throat. He said he’d taken an over-the-counter cough suppressant to help with the cough, but his eyes and lips developed further redness and irritation. On examination, the patient demonstrated conjunctival suffusion, periorbital edema, diffuse oral stomatitis with pseudomembranous crusting, and nasal crusting. His vital signs were within normal limits, and he had no epithelial skin eruptions or erosions in any other mucosal regions. What’s your diagnosis?

Concepts: HIV, Inflammation, Patient, Influenza, Eye puffiness, Common cold, Codeine, Cough medicine


Post-infectious cough is a common symptom associated with common colds and/or upper respiratory tract infection. This cough is expected to last for only for few days and resolve spontaneously, whilst when persists for longer than three weeks is defined “persistent” and is associated tickling or an irritating sensation in the throat which often leads to paroxysms of coughing. Persistent post-infectious cough can cause morbidity since it may interfere with usual living. Despite the recent advances in understanding the mechanisms that regulate cough, in physiological and pathological conditions, current therapeutic options for post-infectious cough are little or only moderately effective.

Concepts: Asthma, Cough, Respiratory system, Upper respiratory tract, Upper respiratory tract infection, Common cold, Dextromethorphan, Cough medicine