Effect of Clomifene on Thyroid Function in Normal Men

Abstract

To study the effect on thyroid function 100 mg of clomifene citrate was given once a day to two groups of healthy male volunteers for 5 and 12 consecutive days, respectively. In both groups serum concentrations of TSH, thyroxine, triiodothyronine, T3 resin uptake test and thyroid hormone binding proteins were measured before, during and after oral administration of clomifene. The effect of clomifene treatment was evaluated in Group 1 by means of serum FSH and LH measurements. Further in Group 2 the serum TSH response to iv TRH (200 \g=m\g) was also investigated.The mean per cent elevations in serum concentrations of FSH and LH were 145 and 200, respectively. In Group 1 a small but statistically significant decrease within reference limits in triiodothyronine (P < 0.01) and free thyroxine index (P < 0.02) was found on day 4 of clomifene. On day 5 a slight increase in TSH was observed (P < 0.05). In Group 2 the response of TSH to TRH showed a non-significant increase after 5 days and a significant increase (P < 0.01) after 12 days of clomifene. Eight days after discontinuation of the drug the response was restored to normal. No changes in the thyroid hormone binding proteins in serum could be demonstrated. Though the observed changes were slight, they indicate that clomifene exerts an influence directly on the thyroid function.The biological actions of clomifene citrate has been attributed to its properties as an anti-oestrogen, as it was thought to block oestrogen receptors in the hypo¬ thalamus and in the pituitary (Roy et al. 196ib,c). Furthermore clomifene was known to have a weak oestrogenic effect (Roy et al. 1964«,b).

An unusual case of vascular hypogonadism treated with clomiphene citrate and testosterone replacement

“…Although we treated the primary hypothyroidism in this case with levothyroxine, we consider the quick and stable result might be attributable to the use of clomiphene, as reported before that clomiphene exerts an influence directly on thyroid function (Sato et al. , 1965; Feldt‐Rasmussen et al. , 1979).…”

Thyroid Function Testing

“…Iodine (iodide and iodine-containing compounds) 445,459,460 Radiologic contrast media, antiseptic, expectorant, antiarrhythmic, and antianginal Lithium 461 Treatment of bipolar psychoses Dopamine antagonists Dopamine receptor blockers (metoclopramide, 462,463 domperidone 464 ) Antiemetic Dopamine-blocking agent (sulpiride 465 ) Tranquilizer Decarboxylase inhibitor (benserazide 466 ) -Dopamine-depleting agent (monoiodotyrosine 462 ) -L-Dopa inhibitors 467 (chlorpromazine, biperiden, haloperidol) Neuroleptic Cimetidine (histamine receptor blocker) 468 Treatment of peptic ulcers Clomiphene (antiestrogen) 257 Induction of ovulation Spironolactone 469 Antihypertensive Amphetamines 470 Anticongestants and antiappetite IL-2 338,339 Immune system modulation…”

“…255,256 A decrease in the free thyroid hormone concentration in serum, albeit minimal in magnitude, might also be responsible for the increase in TSH levels observed during treatment with clomiphene. 257 An increase in serum TSH concentration during lithium therapy is also believed to be caused by reduced thyroid hormone levels rather than by a direct effect of this ion on the pituitary gland.…”