This will be a human laboratory study evaluating the influence of pentoxifylline treatment on the effects of cocaine. Supported by and included in the Helping to End Addiction Long-term® (HEAL) Initiative.

Inclusion Criteria:

1. able to speak/read English,
2. not seeking treatment for drug use at the time of the study,
3. female or male between the ages of 18 and 55 years,
4. recent smoked or intravenous cocaine use verified by benzoylecgonine positive urine, as well as fulfillment of DSM-5 diagnostic criteria for CUD,
5. judged to be medically and psychiatrically healthy by study physicians other than the diagnosis for CUD at the time of screening,
6. ECG, read by a cardiologist, within normal limits,
7. females using an effective form of birth control and not pregnant or breastfeeding and 8) no known contraindications or allergies to pentoxifylline.

Exclusion Criteria:

1. unable to speak/read English,
2. seeking treatment for drug use,
3. under 18 years or over 55 years,
4. no recent smoked or intravenous cocaine use as indicated by benzoylecgonine negative urine and no DSM-5 diagnosis of CUD,
5. judged to be medically or psychiatrically unhealthy by study physicians at the time of screening,
6. ECG, read by a cardiologist, outside normal limits,
7. females not using an effective form of birth control or pregnant or breastfeeding,
8. contraindications or allergies to pentoxifylline, and
9. Self-reported history of head trauma, seizure, CNS tumors, or use of concomitant medications that lower seizure threshold, or first-degree family history of seizures.