Download Thyroid August 1 1999

BEST PRACTICE: THYROID
THYROID REPLACEMENT MEDICATIONS
SUGGESTED TREATMENT PLAN FOR HYPOTHYROIDISM:
Levothyroxine sodium is the treatment of choice for routine management of hypothyroidism. Multisource
(i.e., generic) is therapeutically equivalent to branded Thyroxine.
Adults (< 50 y/o) require 1.7 mcg/kg/day for full replacement – evaluate initially every 6-8 weeks until
TSH normal – evaluate in 2-3 months after dosage adjustments
Older adults (>50 y/o) may require < 1 mcg/kg/day – older patients and younger patients w/history of
cardiac disease, initial dosage is 0.025-0.05mg Levothyroxine/day with clinical and biochemical
reevaluations at 6-8 week intervals under serum TSH is normal.
Older patients w/hypothyroidism for short time (few months) or recently treated for hyperthyroidism
may be treated with full replacement doses
OTHER THYROID HORMONE PREPARATIONS:
Few indications for use of thyroid hormone preparations other than Levothyroxine.
Chronic Liothyronine therapy for hypothyroidism is not recommended due to an association with a
greater degree of iatrogenic hyperthyroidism. Also, elderly are very sensitive to deleterious effects of
Liothyronine.
Biological and synthetic thyroid hormone preparations are not recommended due to fluctuating and
frequently elevated T3 concentrations.
DRUG INTERACTIONS:
Space Levothyroxine administration 4 hours apart from Cholestyramine, Ferrous Sulfate, Sucralfate,
and Aluminum Hydroxide (interfere with Levothyroxine absorption from gut).
Anticonvulsants (Phenytoin, Carbamazepine) and antituberculosis agent Rifampin may require higher
Levothyroxine doses (due to acceleration of Levothyroxine metabolism).
MEDICATION
T4/T3
Ratio
SOURCE
ADULT COMPARATIVE
Q day DOSAGE
(=60mg Thyroid Equivalent)
60mg QD
AWP COST
per 100 tablets
Thyroid USP
T4/T3
Desiccated
$ 6 generic
(Armour Thyroid, Thyrar)
animal thyroid
$ 11 brand
USE RARELY – LAST RESORT
glands
Levothyroxine
T4
Synthetic
0.05mg QD
$ 5 generic
(Synthroid, Levothroid)
(~60mg Thyroid)
$ 23 brand
**PREFERRED TREATMENT**
Liothyronine Sodium
T3
Synthetic
25mcg QD
(no generic)
(Cytomel, Triostat)
(15-37.5mcg ~60mg)
$ 24 brand
Liotrix
4:1
Synthetic
60mg QD
(no generic)
(Thyrolar)
$ 52 brand
NOTES: 1) Thyroglobulin (Proloid) is no longer manufactured. 2) Levothyroxine equivalent dosage was
previously thought to be 0.1mg = 60mg Thyroid, but is now known to be 0.05-0.06mg = 60mg Thyroid.
References: Medical Economics RedBook, ReadyPrice, 8-1999.
JAMA, 3/8/95—Vol. 273, No. 10
For Comments/Questions: Craig Stern, Pharm.D., Pharmacy Benefit Consultant toll free at (888) 701-5438
or E-mail [email protected]
BP_THYROID_8-1999.DOC
Patient Education Notes: 1) Urge your patients to ask for multisource (generic) products when they fill their prescriptions. 2)
Use OTC medications for symptomatic treatment whenever appropriate. 3) Triage patients to their Pharmacist for counseling
about self-treatment.