Impact of Pregnancy on Buprenorphine Pharmacokinetics and Pharmacodynamics

Inclusion Criteria: * Age between 18 - 45 years * Currently on a stable two, three, four, or five times daily dose of sublingual BUP * Willingness to participate in at least one pharmacokinetic(PK)/pharmacodynamics study either during pregnancy or in postpartum\* * Gestational age \< 19 6/7 weeks \* * Singleton gestation * Able to give informed consent and undergo study procedures * Willing to have urine samples screened for the presence of alcohol, barbiturates, opiates, cocaine (or metabolites), benzodiazepines, synthetic opioids and phencyclidine * Requirement applies only to those subjects in the PK study Exclusion Criteria: * Major fetal anomalies or malformations * HIV or AIDS * Comorbid dependence on benzodiazepines or other central nervous system depressants (including anti-seizure medications) * Taking medication known to interfere with buprenorphine metabolism * Active or chronic suicidal or homicidal ideation or attempts * Elevated liver enzymes (AST, alanine aminotransferase (ALT) \> 2 times normal) \* * Creatinine \> 1.5 mg/dl \* * Delivery at other institution where outcome data or samples cannot be obtained on mother and baby * Active use of non- prescribed opiates/opioids detected during the urine drug screen performed within 1 week prior to each PK visit \* * Hematocrit \<28 \* * Requirement applies only to those subjects in the PK study There are several parts to this study and subjects may participate in the PK study and/or one or more procedures …