RF32 | PSUN65 Effect of Oral Contraceptive Medication on Blood Pressure, Plasma Renin, and Aldosterone Levels

BACKGROUND: Combination oral contraceptive medications may cause elevations of plasma renin activity and aldosterone levels. CLINICAL CASE: A 20-year-old female with a past medical history of chronic migraines and allergic rhinitis was referred to endocrinology for evaluation of secondary hypertension after she was found to have elevated renin levels by her primary care physician. The patient was noted to be hypertensive during a tonsillectomy 4 months prior and had also experienced an increased frequency of headaches prompting an evaluation for secondary hypertension and the initiation of lisinopril 10 mg daily. Her other medications included levocetirizine, biotin, and the combined oral contraceptive pill (OCP) norgestimate-ethinyl estradiol (0.25 mg/0.035 mg). Physical examination was remarkable for blood pressure 130/85mmHg, Pulse rate 77, BMI 30 kg/m(2), pale striae on upper arms, lower back and abdomen, and a slight fat pad on the posterior nape of her neck. Initial lab results revealed normal plasma sodium, potassium, metanephrines and normetanephrines, plasma renin activity (PRA) 70.657 ng/mL/h (0.167-5.380 ng/mL/h), aldosterone 18.9 ng/dL (0.0-30.0 ng/dL), and 8: 00 amcortisol 30.3 mcg/dL (6.2-19.4mcg/dL). Doppler ultrasound and magnetic resonance angiography excluded renal artery stenosis and abdominal renin-secreting tumors. Owing to concern about OCP interference with the measurements of PRA and aldosterone levels, these tests were repeated at the end of a seven-day OCP placebo pills and biotin withdrawal. Lab results revealed: PRA >178 ng/mL/h, aldosterone 15.3 ng/dL, 1 mg overnight dexamethasone suppression test cortisol 1.1 mcg/dL, and 24-hour urinary cortisol 22.4 mcg/L (normal value <24mcg/L). Subsequently, the patient agreed to discontinue OCP and biotin and have labs redrawn 6 weeks later, which revealed PRA of 0.9 ng/mL/h and aldosterone of 5.9 ng/dL. Her blood pressure also normalized off the oral contraceptive and lisinopril was successfully discontinued. CONCLUSION: This case report demonstrates the clinically significant impact of oral contraceptive medication on blood pressure, plasma renin activity and aldosterone levels. It's well known that oral contraceptives may cause elevations in PRA and aldosterone1 likely due to an upregulation of angiotensin mediated by the effect of ethinyl estradiol on the hepatocytes(1), albeit not previously reported of the magnitude found in our patient. The extreme elevations of PRA and aldosterone in our patient suggested a diagnosis of either renovascular hypertension, renin secreting neoplasm or coarctation of aorta all of which were excluded. The subsequent normalization of blood pressure, PRA and Aldosterone off oral contraception×6 weeks confirmed that the OCP was the source of her hypertension and lab abnormalities. This case highlights the importance of identifying and omitting interfering medications when evaluating patients for secondary causes of hypertension. REFERENCES: Oelkers WK. Effects of estrogens and progestogens on the renin- aldosterone system and blood pressure. Steroids 1996;61: 166–71. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Monday, June 13, 2022 12:36 p.m. - 12:41 p.m.