Endocrine Abstracts

Synthetic levothyroxine (L-Thyroxine) is the treatment of choice for hypothyroidism. It is safe, effective and generally well tolerated. Some patients, however, cannot tolerate L-Thyroxine. There is still some controversy about the effectiveness of combination T4 & T3 therapy. We describe 3 patients who were successfully treated with Armour thyroid (pork extract of T4 & T3) after being intolerant to L-Thyroxine.

A 35 yr old lady initially presented with fatigue and weight gain and was commenced on L-Thyroxine for autoimmune hypothyroidism. Over the next year, despite being on 150 mcg and TSH being in mid-normal range of 2.62 mIU/L, she remained poly-symptomatic with tiredness, poor memory, headache, and emotional lability. Short synacthen test (SST) was normal and thyroid auto-antibody was negative. There was no evidence of any poly-endocrinopathy. She was commenced on Armour thyroid. Within a few weeks her symptoms improved significantly and within 2 months of starting Armour, her FT4 was 15 pmol/L and TSH 0.67 mIU/L and she was continued on Armour thereafter.

A 63 yr old lady with diagnosed hypothyroidism was started on 25 mcg thyroxine by her GP. She became dizzy, felt nauseous, and had headaches. SST was normal and she had negative thyroid antibodies. When seen in clinic she was tired and her TSH was 9 mIU/L. Leothyronine (LT3) was started but she couldn’t tolerate this either. She was subsequently started on Armour thyroid, which led to considerable improvement in her symptoms within a few weeks and her TSH normalized to 4.03 mIU/L and normal FT4 of 9pmol/L in three months time.

A 40 yr old female was diagnosed with autoimmune thyroiditis and was started on 25 mcg of L-Thyroxine, which was gradually increased to 100 mcg. Over the years her symptoms of tiredness, mood swings, poor memory persisted and she claimed to feel more and more unwell and stopped taking her L-Thyroxine. Her thyroid function deteriorated with a TSH of 31.49 mIU/L within 6 months. She was started on Armour thyroid extract and within a few months she became biochemically euthyroid and was completely symptom free.

Armour thyroid is a natural desiccated thyroid extract derived from pork (T4:T3 in 3:1 ratio). Currently it has to be imported from US where it has been used successfully and safely for some time. Although L-Thyroxine remains the treatment of choice in the majority, a trial of Armour could be considered in patients who have not responded to this conventional treatment and who remain symptomatic with raised serum TSH levels.