There are many product forms of DXM available for treating dry cough, and each form has its features and properties. Dextromethorphan products are sold in the USA market in the form of liquid, pills, capsules, powder, and drops. The DXM products are accessible in most OTC cold and cough medicines for both children and adults.
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DXM Cough Syrups
Cough syrups with dextromethorphan are available under many brands. Each brand of cough syrups with DXM has a different amount of it. The cough syrups with DXM only are measured with a special dosing spoon or syringe, not a regular tablespoon. There are two primary dosage forms of cough syrup DXM, Dextromethorphan Hbr, and Polistirex. DXM Hbr cough syrup is an immediate release preparation, but Polistirex is a sustained released syrup.
A single 60 mg dose of DXM Polistirex provides plasma concentrations similar to two 30 mg of DXM HBr.
What is dextromethorphan HBr? DXM hydrobromide is the water-soluble salt of dextromethorphan and hydrobromic acid, a codeine analog of levorphanol, without any opiate effects. It has an antitussive activity with no analgesic or addictive effect. How does dextromethorphan work in its HBr form? Dextromethorphan hydrobromide enters the bloodstream, crosses the blood-brain barrier, and activates sigma opioid receptors centrally on the cough center.
The main properties and features of HBr form:
- DXM Hbr effect appears after 20 minutes to 1 hour of its ingestion and rapidly absorbed from the gastrointestinal tract. Dextromethorphan HBr half-life is about four hours.
- There are no studies about the use of this form of dextromethorphan while breastfeeding. So, it is recommended to consult a healthcare provider before using a cough medicine with dextromethorphan during lactation.
- Avoid combining the hydrobromide form of DXM and alcohol for recreational use, as hazardous synergistic effects may occur.
- Co-administration of DXM hydrobromide with other OTC cold remedies increases risk of dextromethorphan side effects.
- It is recommended to use Dextromethorphan Hbr as prescribed or according to label instructions, to avoid the occurrence of dextromethorphan overdose.
Most often dextromethorphan Hbr is available under the brand “Benylin Dry Coughs.” Every 5 ml of the syrup contains 7.5 mg of DXM Hbr. Benylin Dry Coughs is pale brown colored with juicy peach taste. It is used four times daily using a special spoon, not a tablespoon. Benylin Dry Coughs can be taken with or without food with a full glass of water (240 milliliters).
“Creomulsion” is another product containing DXM HBr only, which has the most strong adult formula. It is forbidden to use this formula for children under the 6 y.o.
DXM Polistirex is a non-opioid antitussive with no expectorant activity. According to a study published in the U.S. The National Library of Medicine, dextromethorphan Polistirex has an effect in treating neuropathic pain.
Polistirex is a time-release formulation of DXM. The active ingredient is surrounded by a sulfonated styrene-divinylbenzene copolymer complex, an edible plastic.
While taking it orally, the plastic layer is slowly dissolved in the stomach and releasing the drug in the blood over 12 hours. It is the only OTC cough syrup having this characteristic.
In contrast to DXM Hbr, which is absorbed quickly, Polistirex has a longer duration of cough suppression. The plasma half-life of polistirex is about 12 hours, and antitussive activity can last for 6 hours.
The features of Polistirex form:
- Dextromethorphan polistirex is available under the brand “Delsym” (or “Dextromethorphan Polistirex Oral Suspension”)
- It is used for treating dry cough.
- Every 5 ml of dextromethorphan Delsym is equivalent to 30 mg of dextromethorphan HBr.
- Delsym is used twice daily using a special dosing cup, not a regular tablespoon.
- It is free from alcohol and sulfite.
- The polistirex form can be taken with or without food with a full glass of water.
- Delsym is available in the market as an orange-colored liquid with grape and orange taste.
Dextromethorphan pills are used for treating dry cough by inhibiting the excitability of the cough. DXM pills are primarily used for replacing codeine as a cough suppressant and have no analgesic actions.
Features and properties of dextromethorphan pills:
- After oral administration, DXM tablets are completely absorbed from the gastrointestinal tract. The pills start to act during 10-30 minutes after ingestion; the duration of therapeutic action is about 5-6 hours for adults and 6-9 hours for children.
- The half-life of dextromethorphan tablets is about 2 hours. It is metabolized in the liver and excreted as unchanged DXM and demethylated metabolites by the kidney.
- A variety of pure dextromethorphan pills brands are available throughout the world, such as “Romilar”, “Acodin“, and “Resilar“, but none are in the U.S. DXM pills are white colored with a rounded shape. Each brand has a different pill imprint.
- Each dextromethorphan tablet contains dextromethorphan HBr in a concentration, 15 mg or 30 mg, but some brands contain 60 mg of DXM HBr.
The DXM gel caps are used for treating nonproductive cough centrally. After oral administration, DXM capsules are entirely absorbed from the gastrointestinal tract, and their effect begins after 30 minutes of ingestion. The duration of the therapeutic action of the capsule is about 8 hours. It has first-pass metabolism by the liver and is excreted as unchanged DXM and demethylated metabolites in the urine.
The characteristics of DXM gel capsules:
- Dextromethorphan gel caps are available under different brands, such as “Robafen”, “Robitussin”, and “Drixoral”. The most frequent brand in the U.S. is Drixoral Cough Liquid Caps.
- The gel capsule is red-colored with an oval shape. Each capsule has a specific imprint code.
- The liquid inside capsules is actually clear.
- The capsules are somewhat large and difficult to take without water to wash them down. It can be taken with or without food.
- Absorption of the gel caps takes some time and can be accelerated by cracking each gelcap in the mouth before swallowing.
- The liquid inside gelcaps has a bad and bitter taste.
Pure DXM powder is sold legally to pharmaceutical companies for manufacturing cough and cold products. Variable quantities of dextromethorphan powder in multiples of 1 gram can be purchased from the worldwide web, including e-Bay. A concentrated pure dextromethorphan powder can be obtained in different ways by extraction from different cough and cold OTC tablets. The powder purchased from such sites contains no other active ingredients, which greatly increases the risk of overdose. It is not available in its powder form in the U.S.
The features and properties of DXM powder:
- DXM powder contains dextromethorphan HBr only.
- Pure DXM powder is available under many brands, and the most common one is “Romilar.”
- Dextromethorphan HBr is a white to slightly yellow odorless crystalline powder, insoluble in water, and freely soluble in chloroform. It is stable under recommended storage conditions.
- When DXM powder is heated, it emits poisonous fumes of nitrogen oxides.
Most drug abusers ingest dextromethorphan orally.
However, some take the raw powder form of the drug by snorting, leading to increasing the risk of dextromethorphan overdose side effects.
Using the powder form of DXM and weed recreationally increases the risk of DXM dangerous side effects. Moreover, taking the powder to get high, one may experience dextromethorphan withdrawal symptoms when stopping taking it.
Dextromethorphan Cough Drops
Dextromethorphan lozenges are used to temporarily suppress coughing due to mild sore throat and bronchial irritations. The effect of drops starts during 15-30 minute after sucking. The duration of action of hard candies is less than 6 hours.
The features of cough drops with DXM:
- There are several brands of cough drops with dextromethorphan, such as, “Holds DM”, “Sucrets“, “Delsym,” and “Strepsils Dry Cough.”
- DXM cough drops are available in several shapes (oval, round, radiant, and diamond), different tastes (lemon, cherry, menthol, and peppermint), and various colors (white, yellow, red, blue, rose, and green).
- Each brand has a specific imprint code.
Cough lozenge contains the active ingredient dextromethorphan HBr. Each brand has a different amount of DXM HBr. The most common concentrations are 7 mg, 7.5 mg, and 15 mg per lozenge. 30 mg of DXM HBr per lozenge is also available but less common. It is recommended to suck lozenges, not to chew, break, crush, or swallow it whole. If DXM lozenges are taken regularly, take the missed dose as soon as possible. There are combinations of DXM, and other substances exists in the form of drops. These combinations are available in several brands, such as “Robitussin” and “Mucinex DM” lozenges.
What Form And Product of DXM To Choose?
Dextromethorphan substance class is available in many product forms, which help to cope with the different stages of cough and depending on individual needs. The DXM syrup is safe for both children and adults when used as recommended. Dextromethorphan polistirex is preferred than dextromethorphan HBr because of its longer duration of cough suppression. It is advised not to use different DXM forms without consulting a doctor. However, using an OTC cold medicine without dextromethorphan is preferred, to avoid the risk of DXM side effects. The misuse of DXM can cause drug abuse. The success in treating the addiction depends on how long a person remains addicted, how much the drug is consumed and how badly the state of the body is. Also, finding the proper rehab center will accelerate the chance for a successful recovery.
- National Institute of Dental and Craniofacial Research (NIDCR) Interventional Study. Dextromethorphan Versus Placebo for Neuropathic Pain 2008. https://clinicaltrials.gov/ct2/show/NCT00001344