Dextromethorphan should only be used according to the label or package directions. Do not take more than the recommended amount of dextromethorphan in a 24-hour period. Refer to the package or prescription label to determine the amount contained in each dose. Taking dextromethorphan in large amounts can cause serious side effects or death.
Nonprescription cough and cold combination products, including products that contain dextromethorphan, can cause serious side effects or death in young children. Do not give these products to children younger than 4 years of age. If you give these products to children 4-11 years of age, use caution and follow the package directions carefully.
If you are giving dextromethorphan or a combination product that contains dextromethorphan to a child, read the package label carefully to be sure that it is the right product for a child of that age. Do not give dextromethorphan products that are made for adults to children.
Before you give a dextromethorphan product to a child, check the package label to find out how much medication the child should receive. Give the dose that matches the child's age on the chart. Ask the child's doctor if you don't know how much medication to give the child.
Dextromethorphan is usually taken as needed. If your doctor has told you to take dextromethorphan regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
This medication is used for temporary relief of coughs without phlegm that are caused by certain infections of the air passages (such as sinusitis, common cold). This product should not usually be used for an ongoing cough from smoking or long-term breathing problems (such as chronic bronchitis, emphysema) unless directed by your doctor. This product contains dextromethorphan. It is a cough suppressant that works by decreasing the feeling of needing to cough.Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Ask your doctor or pharmacist for more details about using your product safely.These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345. Precautions Before taking dextromethorphan, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
It is in the morphinan class of medications with sedative, dissociative, and stimulant properties (at lower doses). Dextromethorphan does not have a significant affinity for the mu-opioid receptor activity typical of morphinan compounds and exerts its therapeutic effects through several other receptors. In its pure form, dextromethorphan occurs as a white powder.
Dextromethorphan is also used recreationally. When exceeding approved dosages, dextromethorphan acts as a dissociative hallucinogen. It has multiple mechanisms of action, including actions as a nonselective serotonin reuptake inhibitor and a sigma-1 receptor agonist. Dextromethorphan and its major metabolite, dextrorphan, also block the NMDA receptor at high doses, which produces effects similar to other dissociative anesthetics such as ketamine, nitrous oxide, and phencyclidine.
The primary use of dextromethorphan is as a cough suppressant, for the temporary relief of cough caused by minor throat and bronchial irritation (such as commonly accompanies the flu and common cold), or from inhaled particle irritants, as well as chronic cough at a higher dosage.
In 2010, the FDA approved the combination drug dextromethorphan/quinidine for the treatment of pseudobulbar affect (uncontrollable laughing/crying). Dextromethorphan is the actual therapeutic agent in the combination; quinidine merely serves to inhibit the enzymatic degradation of dextromethorphan and thereby increase its circulating concentrations via inhibition of CYP2D6.
Dextromethorphan is available alone in the form of cough syrup and pills as well as in combination with other agents. As a pharmaceutical drug, it is available as dextromethorphan/quinidine (Nuedexta) for the treatment of pseudobulbar affect and as dextromethorphan/bupropion (Auvelity) for treatment-resistant major depressive disorder.
Because dextromethorphan can trigger a histamine release (allergic reaction), atopic children, who are especially susceptible to allergic reactions, should be administered dextromethorphan only if absolutely necessary, and only under the strict supervision of a healthcare professional.
Dextromethorphan was once thought to cause Olney's lesions when administered intravenously; however, this was later proven inconclusive, due to lack of research on humans. Tests were performed on rats, giving them 50 mg or more every day for as long as a month. Neurotoxic changes, including vacuolation, have been observed in posterior cingulate and retrosplenial cortices of rats administered other NMDA receptor antagonists such as PCP, but not with dextromethorphan.
In many documented cases, dextromethorphan has produced psychological dependence in people who used it recreationally. It is considered less addictive than other common cough suppressants, such as the weak opiate codeine. Since dextromethorphan also acts as a serotonin reuptake inhibitor, users report that regular recreational use over a long period of time can cause withdrawal symptoms similar to those of antidepressant discontinuation syndrome. Additionally, disturbances have been reported in sleep, senses, movement, mood, and thinking.
Episodic acute psychosis can occur when high doses of dextromethorphan are taken for recreational use, and an abundance of psychiatric symptoms can result, including dissociation and other PCP-like symptoms.
Serotonin syndrome may result from the combined use of dextromethorphan and serotonergic antidepressants such as selective serotonin reuptake inhibitor (SSRIs) or monoamine oxidase inhibitor (MAOIs). Further research is needed to determine whether doses of dextromethorphan beyond those normally used therapeutically are needed to produce this effect. In any case, dextromethorphan should not be taken with MAOIs due to the possibility of this complication. Serotonin syndrome is a potentially life-threatening condition that can occur rapidly, due to a buildup of an excessive amount of serotonin in the body.
Patients who are taking dextromethorphan should exercise caution when drinking grapefruit juice or eating grapefruit, as compounds in grapefruit affect a number of drugs, including dextromethorphan, through the inhibition of the cytochrome P450 system in the liver, and can lead to excessive accumulation of the drug which both increases and prolongs effects. Grapefruit and grapefruit juices (especially white grapefruit juice, but also including other citrus fruits such as bergamot and lime, as well as a number of noncitrus fruits) generally are recommended to be avoided while using dextromethorphan and numerous other medications.
Dextromethorphan is a prodrug of dextrorphan, which is the actual mediator of most of its dissociative effects through acting as a more potent NMDA receptor antagonist than dextromethorphan itself. What role, if any, (+)-3-methoxymorphinan, dextromethorphan's other major metabolite, plays in its effects is not entirely clear.
At therapeutic doses, dextromethorphan acts centrally (meaning that it acts on the brain) as opposed to locally (on the respiratory tract). It elevates the threshold for coughing, without inhibiting ciliary activity. Dextromethorphan is rapidly absorbed from the gastrointestinal tract and converted into the active metabolite dextrorphan in the liver by the cytochrome P450 enzyme CYP2D6. The average dose necessary for effective antitussive therapy is between 10 and 45 mg, depending on the individual. The International Society for the Study of Cough recommends "an adequate first dose of medication is 60 mg in the adult and repeat dosing should be infrequent rather than qds recommended."
Dextromethorphan has an elimination half-life of approximately 4 hours in individuals with an extensive metabolizer phenotype; this is increased to approximately 13 hours when dextromethorphan is given in combination with quinidine. The duration of action after oral administration is about three to eight hours for dextromethorphan hydrobromide, and 10 to 12 hours for dextromethorphan polistirex. Around one in 10 of the Caucasian population has little or no CYP2D6 enzyme activity, leading to long-lived high drug levels.
The first pass through the hepatic portal vein results in some of the drug being metabolized by O-demethylation into an active metabolite of dextromethorphan called dextrorphan, the 3-hydroxy derivative of dextromethorphan. The therapeutic activity of dextromethorphan is believed to be caused by both the drug and this metabolite. Dextromethorphan also undergoes N-demethylation (to 3-methoxymorphinan or MEM), and partial conjugation with glucuronic acid and sulfate ions. Hours after dextromethorphan therapy, (in humans) the metabolites (+)-3-hydroxy-N-methylmorphinan, (+)-3-morphinan, and traces of the unchanged drug are detectable in the urine. 350c69d7ab