The concomitant prescribing of ethinyl estradiol/drospirenone and potentially interacting drugs.
BACKGROUND
Ethinyl estradiol 0.03 mg/drospirenone 3 mg (EE/DRSP) contains a progestin drospirenone with antimineralocorticoid properties that may cause potassium retention leading to hyperkalemia. We estimated the percentage of EE/DRSP users prescribed concomitant potassium-sparing drugs [nonsteroidal antiinflammatory drugs, diuretics, angiotensin-converting enzyme inhibitors (with diuretics), angiotensin II agonists (with diuretics), and potassium chloride] between January 1, 2002, and March 31, 2005.


METHODS
We analyzed a population-based data set of 62,527 EE/DRSP users (Dimension Rx, Caremark). We compared the fill date and end date for each prescription (Rx) for an interacting drug to the start and end date for each EE/DRSP episode (linked Rxs). If a day of an interacting Rx overlapped with an EE/DRSP episode, concomitant prescribing was recorded.


RESULTS
A total of 17.6% of the women concomitantly used EE/DRSP and an interacting drug. Twenty-nine percent of concomitant use occurred within a month of EE/DRSP initiation. Nonsteroidal antiinflammatory drugs and diuretics were most frequently used concomitantly with EE/DRSP. Forty percent of the women with concomitant use were 35 yearsof age or older at EE/DRSP initiation compared with 29% without concomitant use (p<.001). Obstetricians/gynecologists and family practitioners were the most common prescribers of EE/DRSP and potassium-sparing drugs, respectively.


CONCLUSIONS
Concomitant prescribing of EE/DRSP and potassium-sparing drugs occurred frequently in our study population. As EE/DRSP becomes more widely used, physicians prescribing it should monitor patients for potassium-sparing drug use.
McAdams
Mara
M
Office of Surveillance and Epidemiology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993-0002, USA. mara.mcadams@fda.hhs.gov
Staffa
Judy A
JA
Dal Pan
Gerald J
GJ
D000328:Adult; D000736:Androstenes / Q000009:adverse effects / Q000627:therapeutic use*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D015331:Cohort Studies; D003278:Contraceptives, Oral, Hormonal / Q000009:adverse effects / Q000627:therapeutic use; D016208:Databases, Factual; D004338:Drug Combinations; D004347:Drug Interactions; D004997:Ethinyl Estradiol / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006947:Hyperkalemia / Q000139:chemically induced* / Q000517:prevention & control*; D008485:Medical Audit; D000451:Mineralocorticoid Receptor Antagonists / Q000627:therapeutic use*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012189:Retrospective Studies; D026941:Sodium Channel Blockers / Q000627:therapeutic use*
D000736:Androstenes; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003278:Contraceptives, Oral, Hormonal; D004338:Drug Combinations; D000451:Mineralocorticoid Receptor Antagonists; D026941:Sodium Channel Blockers; D004997:Ethinyl Estradiol; C035144:drospirenone