Since up to 30 days of methadone may be prescribed at one time in the U.S. for take-home, there has been concern about the extended shelf life of liquid methadone. Manufacturers can provide little guidance once the seal of the original container is broken and methadone maintenance treatment (MMT) clinic staff add other ingredients to the product. Independent research and commentary confirms that methadone itself is a stable medication. In one published report, pharmacists noted that potential problems relate more to what is used to dilute the methadone at the time of dispensing, due to possible contamination with mold or fungal growth.
Bacterial growth also might be a concern. One investigation found that storage of methadone mixtures at room temperature fostered visibly unacceptable bacterial growth within 2 weeks, unless appropriate preservatives were included (such as, sodium benzoate). As for potency, methadone mixed with Kool-Aid, Tang, apple juice, or Crystal Light and refrigerated (41°F) maintained its strength for 30 days or much longer.
Based on a review of existing literature and a consensus of opinion among consulted pharmacists, the American Association for the Treatment of Opioid Dependence (AATOD) issued several recommendations in June 2004:
1. Dilution of methadone products should be with distilled water only.
2. New, clean, air tight, light resistant containers should be used for dispensing.
3. Take-home containers should be securely refrigerated as soon as possible, and remain refrigerated until used.
AATOD specified that, if hese procedures are followed, liquid methadone should remain stable for up to 30 days from the date of Methadone Maintenance Clinic dispensing.
However, there may be a question as to whether
dilution at the time of clinic dispensing is required
Federal Regulations do not specifically require
4] Typically, product labeling specifies, “to be diluted with water or other liquid to 30 mL (1 fluid oz.) or more before oral administration.” This could mean dilution “just before the dose is taken,” in which case the patient might be the one to add liquid for dilution. Tap water or other fluid could be used, since storage is not a concern. Dilution simply makes it easier to consume the full amount of otherwise thick, undiluted methadone that is in the take-home container.
1. Allen LV, Stiles ML. Methadone lemonade. U.S. Pharmacist. 1988(September):82.
2. Lauriault G, LeBelle MJ, Lodge BA, Savard C. Stability of methadone in four vehicles for oral administration. AJHP. 1991;48:1252-1256.
3. Parinno MW. Shelf life for methadone hydrochloride products following OTP compounding [memo]. June 11, 2004. AATOD.
4. Federal Register. Opioid drugs in maintenance and detoxification treatment of opiate addiction; final rule. 2001 (Jan 17);66(11):4085. 42 CFR Part 8. Available at: http://www.atforum.com/SiteRoot/pages/addiction_resources/Methadone%20Fed%20Regs.pdf
5. Package Insert. Methadose® Oral Concentrate. 2001. Mallinckrodt, Inc.; St. Louis.
© 2005 Addiction Treatment Forum Updated February 1, 2005