Newsletter 07/2007

2007-09-18

Changeover to Armour Armour ThyroidR from synthetic thyroid hormones
Which dosage of Armour ThyroidR?

Summary

The current NL (07/2007) has a table (tab. 1) that renders the dosage conversion from synthetic thyroid hormone to the natural thyroid hormone Armour Thyroid. Patients taking a combined preparation consisting of T3 and T4 have to multiply the T3 portion by four and add the resulting number to the T4 amount.

Comprehensive version

In the internet discussion forum “Hashimoto Thyroiditis” (1) I spotted a thread on the conversion of synthetic hormone to Armour Thyroid. (2)

Some times ago, our practise released two newsletters on the Armour Thyroid issue. (3, 4)

The US manufacturer (Foster Inc., St. Louis, MO) has released a conversion sheet that is, unfortunately, only valid for the calculation from levothyroxine- into Armour Thyroid dosage (= approximate T4 to Amour equivalent).
For patients under pure levothyroxine this table is very helpful.

For patients with combined medication of levothyroxine and levotriiodthyronine, however, the table is unusable.
Anyhow they still can use it by multiplying times four the T3 quantity (in µg) and by adding the result to T4 quantity (likewise in µg).

Example:
The compound NovothyralR 100 (manufacturer: Merck, AG, Darmstadt, Germany) contains:
1) 100 µg L-T4 and 20 µg L-T3
2) 20 µg L-T3 x 4 = 80 µg L-T4; 80 + 100 = 180 µg L-T4 in total.
3) So the approximate NovothyralR equivalent for L-T4 is 180 µg
4) Finally, the Armour ThyroidR equivalent for 180 µg L-T4 can be picked from the table.

 

Table 1:
Equivalent dosage: Armour ThyroidR vs.synthetic levothyroxine

Armour ThyroidR
Armour dosage (L-T3 + L-T4)		 L-thyroxine
L-thyroxine dosage		 Armour ThyroidR
Dryed qu
¼ grain*
9,5 µg** T4
2,25 µg T3		 25 µg 15 mg***
½ grain
19 µgT4
4,5 µg T3		 50 µg 30 mg
1 grain
38 µg T4
9 µg T3		 100 µg 60 mg
1 ½ grain
57 µg T4
13,5 µg T3		 150 µg 90 mg
2 grain
76 µg T4
18 µg T3		 200 µg 120 mg
3 grain
114 µg T4
27 µg T3		 300 µg 180 mg
4 grain
152 µg T4
36 µg T3		 400 µg 240 mg
5 grain
190 µg T4
45 µg T3		 500 µg 300 mg

* grain: 1 grain = ca. 65 mg
** µg: 1 µg = 1 millionsth gram
*** mg; 1 mg = 1 thousandth gram

References/Sources

  1. http://www.ht-mb.de/forum/showthread.php?t=1072877
  2. Forest Pharmaceuticals, Inc.
    A Subsidiary of Forest Laboratories, Inc.
    St. Louis, MO 63045, USA
  3. http://www.schilddruesenpraxis.de/nl_200701en.shtml
  4. http://www.schilddruesenpraxis.de/nl_200604.shtml

 

(C) 2007 Prof. Hotze