Hypercalcaemia: ethinyl estradiol and norethindrone may decrease plasma calcium.

Clinical bottom line (level 2b-)

  1. In postmenopausal women with hyperparathyroidism, ethinyl estradiol and norethindrone decreased plasma calcium, but not significantly.
  2. There was no clear difference between the two treatments.
Selby and Peacock: New England Journal of Medicine 1986; 314 (23): 1481-1485
Expires June 2003

The study

?blinded unconcealed un-randomised trial without intention-to-treat
Setting: general hospital, UK

17 patients (aged mean 57 years, 100% female) postmenopausal women with hyperparathyroidism (persistently elevated plasma concentration of calcium with inappropriately raised levels of parathyroid hormone, in the absence of any other cause of hypercalcaemia)
Control Group: (n = 6, 6 analysed): ethinyl estradiol 30 µ g daily
Experimental Group: (n = 11, 8 analysed): norethindrone 5 mg daily

82% followed for 6 months

The evidence

Outcome Control Group
(SD)		 Experimental Group
(SD)		 Mean Difference
(95% CI)
mean difference in plasma calcium (mmol/l), baseline to 6 months with ethinyl estradiol 2.77
(0.17) 		2.59
(0.17) 		0.18
(-0.02 to 0.38)
mean difference in plasma calcium, from baseline to 6 months with norethindrone 2.93
(0.27) 		2.75
(0.14) 		0.18
(-0.05 to 0.85)

Comments

  1. The study was too small to show any clear decrease in plasma calcium.
  2. The trial is of low quality as it was not randomised, had a low follow-up, and was in a very small number of patients.

Citation

  1. Selby PL, and Peacock M: Ethinyl estradiol and norethindrone in the treatment of primary hyperparathyroidism in postmenopausal women. New England Journal of Medicine 1986; 314 (23): 1481-1485
Contributor: Clare Wotton and Musab Hayatli, June 2000
Reviewer:

Clinical Question.
Patient postmenopausal women with hyperparathyroidism
Intervention or Exposure ethinyl estradiol
Comparison norethindrone
Outcome plasma calcium