Single-day methadone dose alteration: detectability and symptoms.

Three experiments were conducted in which detectability and symptomatic effects of acute (single-day) increases and decreases in the methadone dose of subjects on methadone maintenance were examined. Altered doses ranged from 0% to 200% of the stable methadone dose, which was typically 50 mg. In an initial experiment, explicit information was provided to subjects (N = 10) about the occurrence and size of altered doses. No explicit information was provided in a second experiment, but subjects (N = 14) could detect altered doses on the basis of taste. In the third experiment, subjects (N = 2) received no information about the direction, size, or schedule of altered doses. Large dose alterations (75% to 100% of stable dose) were reliably detected by subjects on methadone maintenance, although marked individual differences in sensitivity were apparent. With taste cues available, subjects underestimated the magnitude of dose decreases and increases by 50% and 75%. Without taste cues, subjects could reliably detect only decreased doses. Symptomatic effects related to direction and size of altered doses but not to information conditions. Withdrawal symptom checklist scores were elevated after large (75% to 100%) dose decreases under all information conditions, but few symptomatic effects were reported after dose increases under any information condition.