J Endocrinol Metab

Journal of Endocrinology and Metabolism, ISSN 1923-2861 print, 1923-287X online, Open Access

Article copyright, the authors; Journal compilation copyright, J Endocrinol Metab and Elmer Press Inc

Journal website https://jem.elmerpub.com

Original Article

Volume 000, Number 000, May 2026, pages 000-000

Therapeutic Outcomes of Methimazole in Hyperthyroidism Patients

↓ **Table 1.** Baseline Demographic and Clinical Characteristics of the Study Population
Characteristics	N	Percentage (%)
Denominator of the percentage is the total number of subjects in each group. BMI: body mass index; TMN: toxic multinodular goiter.
18–39 years	23	8.3%
30–59 years	172	62.1%
> 59 years	82	29.6%
Male	82	29.6%
Female	195	70.4%
BMI < 18.5	6	2.2%
BMI 18.5–24.9	53	19.1%
BMI 25–29	90	32.5%
BMI 30–34.9	71	25.6%
BMI 35–39	42	15.2%
BMI > 40	14	5.1%
Smokers	26	9.6%
Non-smokers	246	90.4%
Subclinical hyperthyroidism	12	4.4%
Graves’ disease	196	71.5%
TMN/nodule	48	17.5%
Thyroiditis	6	2.2%
Unknown type of hyperthyroidism	12	4.4%

↓ Table 1. Baseline Demographic and Clinical Characteristics of the Study Population

Characteristics

Percentage (%)

Denominator of the percentage is the total number of subjects in each group. BMI: body mass index; TMN: toxic multinodular goiter.

18–39 years

8.3%

30–59 years

172

62.1%

> 59 years

29.6%

Male

29.6%

Female

195

70.4%

BMI < 18.5

2.2%

BMI 18.5–24.9

19.1%

BMI 25–29

32.5%

BMI 30–34.9

25.6%

BMI 35–39

15.2%

BMI > 40

5.1%

Smokers

9.6%

Non-smokers

246

90.4%

Subclinical hyperthyroidism

4.4%

Graves’ disease

196

71.5%

TMN/nodule

17.5%

Thyroiditis

2.2%

Unknown type of hyperthyroidism

4.4%

↓ **Table 2.** Association Between Duration of Methimazole Therapy and Adverse Effects
System	Side effects	0–6 months (n = 65)	6.1–12 months (n = 38)	12.1–24 months (n = 42)	> 24 months (n = 132)	Total (n = 277)	P
Denominator of the percentage is the total number of subjects in each group. ^aChi-square test is used to calculate the P value. ^bFisher’s exact test is used to calculate the P value. In this study, a P value < 0.05 is considered significant.
Gastrointestinal effects	Sore throat	3 (4.8%)	5 (13.2%)	5 (12.2%)	31 (23.8%)	44 (16.2%)	0.0067^a
	Nausea	4 (6.5%)	5 (13.2%)	6 (14.6%)	19 (14.5%)	34 (12.5%)	0.4334^a
	Vomiting	3 (4.8%)	5 (13.2%)	4 (9.8%)	21 (16.0%)	33 (12.1%)	0.1434^b
	Hepatotoxicity	1 (1.6%)	1 (2.6%)	1 (2.4%)	3 (2.3%)	6 (2.2%)	1.0000^b
Musculoskeletal effects	Arthralgia	7 (10.8%)	7 (18.4%)	6 (14.3%)	30 (22.7%)	50 (18.1%)	0.1962^a
Dermatological effects	Rashes	21 (32.3%)	7 (18.4%)	14 (33.3%)	41 (31.1%)	83 (30%)	0.4737^a
	Angioedema	2 (3.2%)	2 (5.3%)	3 (7.3%)	8 (6.1%)	15 (5.5%)	0.7948^b
Hematological effects	Leukopenia	11 (17.7%)	5 (13.2%)	6 (14.6%)	22 (16.8%)	44 (16.2%)	0.9241^a
	Anemia	1 (1.6%)	1 (2.6%)	2 (4.9%)	7 (5.3%)	11 (4.0%)	0.7261^b
	Thrombocytopenia	3 (4.8%)	3 (7.9%)	2 (4.9%)	12 (9.2%)	20 (7.3%)	0.7176^b
	Neutropenia	5 (8.1%)	2 (5.3%)	6 (14.6%)	16 (12.3%)	29 (10.7%)	0.4743^b

↓ Table 2. Association Between Duration of Methimazole Therapy and Adverse Effects

System

Side effects

0–6 months (n = 65)

6.1–12 months (n = 38)

12.1–24 months (n = 42)

> 24 months (n = 132)

Total (n = 277)

Denominator of the percentage is the total number of subjects in each group. ^aChi-square test is used to calculate the P value. ^bFisher’s exact test is used to calculate the P value. In this study, a P value < 0.05 is considered significant.

Gastrointestinal effects

Sore throat

3 (4.8%)

5 (13.2%)

5 (12.2%)

31 (23.8%)

44 (16.2%)

0.0067^a

Nausea

4 (6.5%)

5 (13.2%)

6 (14.6%)

19 (14.5%)

34 (12.5%)

0.4334^a

Vomiting

3 (4.8%)

5 (13.2%)

4 (9.8%)

21 (16.0%)

33 (12.1%)

0.1434^b

Hepatotoxicity

1 (1.6%)

1 (2.6%)

1 (2.4%)

3 (2.3%)

6 (2.2%)

1.0000^b

Musculoskeletal effects

Arthralgia

7 (10.8%)

7 (18.4%)

6 (14.3%)

30 (22.7%)

50 (18.1%)

0.1962^a

Dermatological effects

Rashes

21 (32.3%)

7 (18.4%)

14 (33.3%)

41 (31.1%)

83 (30%)

0.4737^a

Angioedema

2 (3.2%)

2 (5.3%)

3 (7.3%)

8 (6.1%)

15 (5.5%)

0.7948^b

Hematological effects

Leukopenia

11 (17.7%)

5 (13.2%)

6 (14.6%)

22 (16.8%)

44 (16.2%)

0.9241^a

Anemia

1 (1.6%)

1 (2.6%)

2 (4.9%)

7 (5.3%)

11 (4.0%)

0.7261^b

Thrombocytopenia

3 (4.8%)

3 (7.9%)

2 (4.9%)

12 (9.2%)

20 (7.3%)

0.7176^b

Neutropenia

5 (8.1%)

2 (5.3%)

6 (14.6%)

16 (12.3%)

29 (10.7%)

0.4743^b

↓ **Table 3.** Age-Stratified Distribution of Methimazole-Associated Adverse Effects
System	Side effects	18–29 age (n = 23)	30–59 age (n = 172)	> 59 age (n = 82)	Total (n = 277)	P
Denominator of the percentage is the total number of subjects in each group. ^aChi-square test is used to calculate the P value. ^bFisher’s exact test is used to calculate the P value. A P value < 0.05 is considered significant.
Gastrointestinal effects	Sore throat	3 (14.3%)	31 (18.5%)	10 (12.2%)	44 (16.2%)	0.4382^a
	Nausea	4 (19.0%)	20 (11.8%)	10 (12.2%)	34 (12.5%)	0.6381^a
	Vomiting	3 (14.3%)	19 (11.2%)	11 (13.4%)	33 (12.1%)	0.8423^a
	Hepatotoxicity	1 (4.5%)	2 (1.2%)	3 (3.7%)	6 (2.2%)	0.2388^b
Musculoskeletal effects	Arthralgia	2 (8.7%)	24 (14%)	24 (29.3%)	50 (18.1%)	0.1756^a
Dermatological effects	Rashes	10 (43.5%)	48 (27.9%)	25 (27.9%)	83 (30%)	0.5581^a
	Angioedema	1 (4.8%)	5 (3.0%)	9 (11.0%)	15 (5.5%)	0.0317^b
Hematological effects	Leukopenia	3 (14.3%)	23 (13.6%)	18 (22.0%)	44 (16.2%)	0.2354^a
	Anemia	1 (4.8%)	3 (1.8%)	7 (8.5%)	11 (4.0%)	0.0340^b
	Thrombocytopenia	1 (4.5%)	6 (3.6%)	13 (15.9%)	20 (7.3%)	0.0019^a
	Neutropenia	5 (23.8%)	16 (9.5%)	8 (9.8%)	29 (10.7%)	0.1290^a

↓ Table 3. Age-Stratified Distribution of Methimazole-Associated Adverse Effects

System

Side effects

18–29 age (n = 23)

30–59 age (n = 172)

> 59 age (n = 82)

Total (n = 277)

Gastrointestinal effects

Sore throat

3 (14.3%)

31 (18.5%)

10 (12.2%)

44 (16.2%)

0.4382^a

Nausea

4 (19.0%)

20 (11.8%)

10 (12.2%)

34 (12.5%)

0.6381^a

Vomiting

3 (14.3%)

19 (11.2%)

11 (13.4%)

33 (12.1%)

0.8423^a

Hepatotoxicity

1 (4.5%)

2 (1.2%)

3 (3.7%)

6 (2.2%)

0.2388^b

Musculoskeletal effects

Arthralgia

2 (8.7%)

24 (14%)

24 (29.3%)

50 (18.1%)

0.1756^a

Dermatological effects

Rashes

10 (43.5%)

48 (27.9%)

25 (27.9%)

83 (30%)

0.5581^a

Angioedema

1 (4.8%)

5 (3.0%)

9 (11.0%)

15 (5.5%)

0.0317^b

Hematological effects

Leukopenia

3 (14.3%)

23 (13.6%)

18 (22.0%)

44 (16.2%)

0.2354^a

Anemia

1 (4.8%)

3 (1.8%)

7 (8.5%)

11 (4.0%)

0.0340^b

Thrombocytopenia

1 (4.5%)

6 (3.6%)

13 (15.9%)

20 (7.3%)

0.0019^a

Neutropenia

5 (23.8%)

16 (9.5%)

8 (9.8%)

29 (10.7%)

0.1290^a

↓ **Table 4.** Adverse Effects of Methimazole According to Etiology of Hyperthyroidism
System	Side effects	Sub clinical (n = 12)	Graves (n = 196)	TMN/nodule (n = 48)	Thyroiditis (n = 6)	Unknown (n = 12)	Total (n = 274)	P
Denominator of the percentage is the total number of subjects in each group. ^aFisher’s exact test is used to calculate the P value. ^bChi-square test is used to calculate the P value. A P value < 0.05 is considered significant. TMN: toxic multi-nodular; NA: not available.
Gastrointestinal effects	Sore throat	3 (25.0%)	35 (17.9%)	5 (10.9%)	1 (16.7%)	NA	44 (16.4%)	0.4240^a
	Nausea	1 (8.3%)	24 (12.3%)	8 (17.0%)	1 (16.7%)	NA	34 (12.6%)	0.6836^a
	Vomiting	2 (16.7%)	22 (11.3%)	7 (14.9%)	1 (16.7%)	1 (11.1%)	33 (12.3%)	0.7728^a
	Hepatotoxicity	NA	5 (2.6%)	1 (2.1%)	NA	NA	6 (2.2%)	1.0000^a
Musculoskeletal effects	Arthralgia	6 (50%)	33 (16.8%)	10 (20.8%)	0 (0%)	0 (0%)	49 (17.9%)	0.5950^a
Dermatological effects	Rashes	3 (25%)	61 (31.1%)	13 (27.1%)	6 (100%)	0 (0%)	83 (30.3%)	0.4737^b
	Angioedema	1 (8.3%)	8 (4.1%)	4 (8.5%)	2 (33.3%)	NA	15 (5.6%)	0.0521^a
Hematological effects	Leukopenia	2 (16.7%)	31 (15.9%)	8 (17.0%)	2 (33.3%)	1 (11.1%)	44 (16.4%)	0.7698^a
	Anemia	NA	8 (4.1%)	2 (4.3%)	NA	NA	10 (3.7%)	1.0000^a
	Thrombocytopenia	2 (16.7%)	11 (5.6%)	3 (6.4%)	2 (33.3%)	1 (10.0%)	19 (7.0%)	0.0567^a
	Neutropenia	1 (8.3%)	22 (11.3%)	4 (8.5%)	1 (16.7%)	1 (11.1%)	29 (10.8%)	0.9126^a

↓ Table 4. Adverse Effects of Methimazole According to Etiology of Hyperthyroidism

System

Side effects

Sub clinical (n = 12)

Graves (n = 196)

TMN/nodule (n = 48)

Thyroiditis (n = 6)

Unknown (n = 12)

Total (n = 274)

Denominator of the percentage is the total number of subjects in each group. ^aFisher’s exact test is used to calculate the P value. ^bChi-square test is used to calculate the P value. A P value < 0.05 is considered significant. TMN: toxic multi-nodular; NA: not available.

Gastrointestinal effects

Sore throat

3 (25.0%)

35 (17.9%)

5 (10.9%)

1 (16.7%)

44 (16.4%)

0.4240^a

Nausea

1 (8.3%)

24 (12.3%)

8 (17.0%)

1 (16.7%)

34 (12.6%)

0.6836^a

Vomiting

2 (16.7%)

22 (11.3%)

7 (14.9%)

1 (16.7%)

1 (11.1%)

33 (12.3%)

0.7728^a

Hepatotoxicity

5 (2.6%)

1 (2.1%)

6 (2.2%)

1.0000^a

Musculoskeletal effects

Arthralgia

6 (50%)

33 (16.8%)

10 (20.8%)

0 (0%)

49 (17.9%)

0.5950^a

Dermatological effects

Rashes

3 (25%)

61 (31.1%)

13 (27.1%)

6 (100%)

0 (0%)

83 (30.3%)

0.4737^b

Angioedema

1 (8.3%)

8 (4.1%)

4 (8.5%)

2 (33.3%)

15 (5.6%)

0.0521^a

Hematological effects

Leukopenia

2 (16.7%)

31 (15.9%)

8 (17.0%)

2 (33.3%)

1 (11.1%)

44 (16.4%)

0.7698^a

Anemia

8 (4.1%)

2 (4.3%)

10 (3.7%)

1.0000^a

Thrombocytopenia

2 (16.7%)

11 (5.6%)

3 (6.4%)

2 (33.3%)

1 (10.0%)

19 (7.0%)

0.0567^a

Neutropenia

1 (8.3%)

22 (11.3%)

4 (8.5%)

1 (16.7%)

1 (11.1%)

29 (10.8%)

0.9126^a

↓ **Table 5.** Thyroid Function Parameters (T4 and TSH) Before and After Methimazole Therapy
Category	Sub-category	N	Percentage (%)
Denominator of the percentage is the total number of subjects in each group. T4: thyroxine; TSH: thyroid-stimulating hormone; NA: not available.
T4 levels before methimazole	< 5 µg/dL	1	0.4%
	5–12 µg/dL	35	12.8%
	>12 µg/dL	225	82.4%
	NA	12	4.4%
TSH levels before methimazole	< 0.35 µg/dL	233	84.4%
	0.35–4.5 µg/dL	29	10.5%
	> 4.5 µg/dL	4	1.4%
	NA	10	3.6%
T4 levels after methimazole	<5 µg/dL	117	43%
	5–12 µg/dL	151	55.5%
	> 12 µg/dL	4	1.5%
TSH levels after methimazole	<5 µg/dL	41	15%
	5–12 µg/dL	202	73.7%
	> 12 µg/dL	30	10.9%
	NA	1	0.4%

↓ Table 5. Thyroid Function Parameters (T4 and TSH) Before and After Methimazole Therapy