Endocrine Abstracts

A 34-year-old woman, presented to her General Practitioner with hot flushes. Investigations showed her to have a normal LH, FSH, free T4 and TSH. Her prolactin was elevated at 1110 milliunits per litre (NR <350 ). She had a normal menarche age 14 and had regular 28 day menstrual cycles. Before the onset of the hot flushes she had started to take agnus castus, a herbal remedy said to help symptoms of premenstrual tension.

Whilst she continued to take the agnus castus the hot flushes persisted and the prolactin levels remained elevated (1110 milliunits per litre and 2030 milliunits per litre). After 3 months she stopped the agnus castus because of the hot flushes and her prolactin has since become normal.

Agnus castus , has been used to treat the symptoms of Premenstrual Dysphoric Disorder. It has been shown in a placebo-controlled trial of 170 women with Premenstrual Syndrome to result in a significant decrease in irritability, anger, headache and breast fullness. No significant adverse events were reported. Agnus castus is also reported to increase breast milk production, although the mechanism by which this occurs is not clear. In this case it is possible that the agnus castus was responsible for the elevation in prolactin and the symptoms of hot flushes. If she had continued with this herbal treatment she may have developed signs of hyperprolactinaemia such as amenorrhoea or galactorrhoea. She understandably is reluctant to re challenge herself with the drug and so we cannot be certain that it is the cause.

This illustrates the importance of a drug history, as many patients do not spontaneously report the use of herbal medicines.

It also serves as a reminder that herbal treatments are not exposed to the same regulation as traditional medicines, which have to satisfy the drug regulatory authorities before they become available.