Smoked cocaine self-administration in females and voucher incentives for abstinence

There are three purposes for this study: (1) To extend the laboratory study of heavy smoked cocaine use to women, (2) to assess cocaine withdrawal symptoms and (3) to assess the utility of voucher incentives for achieving and maintaining cocaine and other drug abstinence in female cocaine abusers. Methods: Ten non-treatment seeking female cocaine smokers resided inpatient for 4–5 days and could smoke up to 6 doses of cocaine base (50 mg each) twice a day (at 1200 h and again at 1600 h) for 2 consecutive days. During the following 2-week outpatient phase, women were given US$40 in merchandise vouchers if urinalysis indicated lower drug levels from the previous day. Results: Women self-administered 20.4 out of 24 possible doses. Compared to the 1200 session, heart rate and blood pressure, but not subjective effects, were still significantly increased prior to the 1600 session. Nine women completed the outpatient phase, attending 98% of their appointments. Using the One-Half Rule, 56% of urines indicated no new cocaine or other drug use. Implications: Although a US$40 voucher incentive for a “clean” urine was not sufficient to eliminate cocaine use, the possibility of earning the voucher was sufficient to maintain nearly perfect attendance.