Can methadone treatment cause weight gain?/nThe question concerns a 38-year-old man who has been ad

Fråga: Can methadone treatment cause weight gain?

The question concerns a 38-year-old man who has been addicted to heroin for the past 20 years. He was included in the methadone program four years ago, and has mostly been free of illicit drug use. He is now treated with 120 mg methadone daily, and his weight has increased by 45 kg since methadone initiation (he is now weighing 117 kg). The patient also has hepatitis C, chronic obstructive pulmonary disease, hypertension and leg oedema.

Other drugs: propranolol 10 mg x3, candesartan/hydrochlorothiazide (Atacand Plus) once daily, spironolactone 25 mg x1, Oralovite twice daily, omeprazole 20 mg x1 and acamprosate (Campral) 333 mg 3x2, terbutaline (Bricanyl).

Sammanfattning: Weight gain in combination with oedema after high doses of methadone has been observed in some cases. The nutritional status in methadone treated addicts may improve, causing some weight gain.

Svar: One case series of nine patients who developed marked weight gain and oedema during methadone treatment has been published. High doses of liquid methadone HCl (100-120 mg daily) caused weight gain (by up to 40 kg) in combination with generalised swelling of the face, abdomen and upper and lower extremities within three to six months after initiating methadone maintenance therapy for heroin addiction. The report describes three patients in detail, who had to be hospitalised. None of the patients had a prior history of oedema and a detailed evaluation failed to reveal evidence of cardiac, renal, or liver disease, deranged plasma protein levels or salt and water retention. All three patients initially responded to diuretics with an average weight decrease of 6 kg, but later became refractory to this treatment. Lowering the methadone dose in one case, and returning to heroin use in the other two caused partial reversal of the problem (1).

In the Swedish adverse drug reaction register, there are no reports of weight increase after methadone treatment (of a total of 19 reports) (2). In the WHO database there are 15 reports of weight increase (of a total of 3806 reports) (3). The reports in the WHO database are not evaluated as to the cause relationship.

Methadone treatment of heroin addicts may improve the nutritional status in patients causing weight gain, and this has been shown in some studies (4,5,6). In one of these studies, a weight gain from 69.3+/-14.8 to 78.6+/-19.7 was seen after 18 months treatment (4). Similar results, with a mean weight increase of 8.8 kg was seen in men on methadone maintenance treatment after four years. However, in the women a small weight decrease was seen (5). Former heroin addicts maintained on methadone (no doses mentioned) had an increased calorie intake with a median intake of 3070 kcal/day (range 2000-13 500 kcal). However, despite this increased food intake, the majority of the patients maintained a low body weight (7).

In the present case, the weight gain was not accompanied with any generalised swelling or oedema making it different from the published cases. In addition, it is not clear when the weight gain started, and a causal relationship is difficult to establish. Longwell B, Betz T, Horton H, Witte CL, Witte MH. Weight gain and edema on methadone maintenance therapy. Int J Addict 1979; 14(3):329-335. Swedis (The Swedish Drug Information System) (2006-11) Vigibase: WHO:s adverse drug reactions database (2006-11) Kabrt J, Wilczek H, Svobodova J, Haluzik M, Kotrlikova E. (Nutritional status of drug addicts in a methadone program). Cas Lek Cesk 1999;138(22):693-5. (abstract) Kolarzyk E, Jenner B, Szpanowska-Wohn A, Pach D, Szurkowska M. The changes in taste preferences during 4 years period of methadone maintenance treatment. Prezegl Lek 2005;62(6):378-81. (abstract) Szpanowska-Wohn A, Kolarzyk E, Pach D, Targosz D. (Nutritional status of opiate-dependent persons before and during methadone maintenance therapy). Przegl Lek 2004;61(4):339-44. (abstract) Atkinson RL. Opioid regulation of food intake and body weight in humans. Fed Proc 1987; 46(1):178-182.