AHFS Class:

28:08.08 Opioid Agonists

Generic Name

• Methadone Hydrochloride

Methadone hydrochloride is available as a 10 mg/mL injection solution in 20-mL multiple-dose vials.³⁷⁷⁰ Each mL of solution contains methadone hydrochloride 10 mg, sodium chloride 0.9%, chlorobutanol 0.5% as a preservative, and sodium hydroxide and/or hydrochloric acid to adjust the pH.³⁷⁷⁰

Equivalency

Methadone hydrochloride 10 mg is equivalent to 8.95 mg of methadone as the free base.³⁷⁷⁰

pH

From 4.5 to 6.5.³⁷⁷⁰

Methadone hydrochloride may be administered by subcutaneous, intramuscular, or intravenous injection.³⁷⁷⁰

Vials of methadone hydrochloride injection should be stored at controlled room temperature, protected from light, and in the original carton until contents have been used.³⁷⁷⁰

Syringes

In 2015, reports of decreased potency of certain drugs (e.g., methadone hydrochloride) stored in Becton Dickinson syringes for extended periods (i.e., exceeding 24 hours) were confirmed by the manufacturer of these syringes; the cause of this change was later identified to be the inclusion of an alternate rubber stopper in the plunger of certain product lots of syringes.³⁰²⁹; ³⁰³⁶; ³⁰³⁷; ³⁰³⁹; ³⁰⁴¹; ³⁰⁴² Decreased potency was not observed when the syringes were filled and used promptly.³⁰³⁷ Use of the alternate stopper was later discontinued and use of the primary stopper in such syringes was resumed; however, Becton Dickinson states that its general-use syringes are cleared by FDA for immediate use in fluid aspiration and injection and that such syringes, regardless of the stopper material, have not been cleared by FDA for use as a closed-container system.³³⁹¹

Standardize 4 Safety

One or more standardized concentrations for this drug have been established through Standardize 4 Safety (S4S), a national patient safety initiative to reduce medication errors, especially during transitions of care. (See Standardize 4 Safety in Users Guide.) Recommendations developed to date through this initiative are available at www.ashp.org/pharmacy-practice/standardize-4-safety-initiative.

Table 1: Standardize 4 Safety Epidural Standard Concentrations for Methadone as a Single Drug³⁹⁹⁰

Solution Compatibility

Y-Site Injection Compatibility (1:1 Mixture)

For a list of references cited in the text of this monograph, search the monograph titled References.

ASHP^® Injectable Drug Information^TM. Selected Revisions September 12, 2024. © Copyright, 2024. American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.