Table 2.

Characteristics of clinical trials of synthetic combination therapy

Authors	Year	Participants, n (total n = 1,257)	Mean age, years	Sex, % F	Dose LT3	Dosing frequency	Approximate µg ratio of T4:T3	Duration
Appelhof [53]	2005	130	46–49	83–89	LT4/LT3 10:1 or 5:1	Twice daily	10:1 or 5:1	15 weeks
Bunevicius [46]	1999	33	46	94	LT4 −50 µg/day, LT3 +12.5 µg/day	Once daily	10:1	5 weeks
Bunevicius [51]	2002	10	34	100	LT4 −50 µg/day, LT3 +10.0 µg/day	Once daily	6.5:1	5 weeks
Clyde [17]	2003	44	43–45	77–86	LT4 −50 µg/day, LT3 +15.0 µg/day	Twice daily	6.5:1	4 months
Escobar-Morreale [49]	2005	26	48	100	LT4 75 µg/day, LT3 +5 µg/day	Once daily	15:1 or 12:1	8 weeks
Fadeyev [78]	2010	36	40–43	100	LT4 −25 µg/day, LT3 +12.5 µg/day	Once daily	6:1	6 months
Kaminski [79]	2016	32	43	94	LT4 75 µg + 15 µg LT3/day	Once daily	5:1	8 weeks
Nygaard [23]	2009	59	46–47	93	LT4 −50 µg/day, LT3 +20 or 50.0 µg/day	Once daily	4:1	12 weeks
Rodriguez [59]	2005	27	47	83	LT4 −50 µg/day, LT3 +10.0 µg/day	Once daily	7:1	6 weeks
Saravanan [47]	2005	573	57	83–84	LT4 −50 µg/day, LT3 +10.0 µg/day	Once daily	8:1	12 months
Sawka [60]	2003	33	49	90	LT4 −50 µg/day, LT3 +25.0 µg/day	Twice daily	3.5:1	15 weeks
Siegmund [71]	2004	23	23–69	81	LT4 −5% + LT3 5% aim 14:1 ratio	Once daily	19:1	12 weeks
Valizadeh [48]	2009	60	38–39	80	LT4 −50 µg/day, LT3 +12.5 µg/day	Twice daily	4:1	4 months
Walsh [52]	2003	101	48	92	LT4 −50 µg/day, LT3 +10.0 µg/day	Once daily	8.5:1	10 weeks
Hoang [58]	2013	70	51	76	1 mg extract for each 1.667 usual LT4 dose	Once daily	4:1	16 weeks

Italics indicates desiccated thyroid extract. Reprinted with adaptations with permission from Taylor & Francis Ltd. from Jonklaas [104].