The tricyclic antidepressant amitriptyline was suspected to be abused among methadone maintenance treatment (MMT) patients in Israel. Given its potentially dangerous interaction with methadone, and even more so with benzodiazepines (BDZ), which is highly abused among MMT patients, we did a cross sectional studied all 303 patients (February, 2007).

Evidence of tricyclics presence in one of the 2±0.5 random urine samples (range1-4) that are routinely taken for opiates, cocaine BDZ, amphetamines, and cannabis. Modified addiction severity index (ASI) and variables from patients’ records.

48(15.8%) were positive for amitriptyline. They were similar to the others in age, gender, presence of DSM-IV psychiatric disorders, and QTc interval on ECG. Logistic regression (multivariate analyses) found that the extent of being amitriptyline positive was higher in BDZ abusers (OR=11.6 95%CI 4.4-30.7), in subjects with positive antibody to hepatitis C (OR=2.2, 95%CI 1.02-4.9) and in patients treated with high dose methadone (>150 mg/day) (OR=2.4, 95%CI 1.2-4.9). Amitriptyline was found in 12 (7.5%) of the “privileged” group members who, by definition, should not be abusing drugs.

The high prevalence of amitriptyline abuse, even among “privileged” patients, and in combination with BDZ abuse, emphasizes the importance of routine monitoring in order to decrease the potential risk associated with amitriptyline combined with methadone and BDZ, and to implement appropriate interventions.