Ethionamide (Eto) and Prothionamide (Pto)

Therapeutic action

– Antibacterials (thioamides) with bactericidal and bacteriostatic activity

Presentation

– 250 mg tablet

Dosage

– Child under 30 kg: 15 to 20 mg/kg/day in 2 divided doses or once daily if tolerated
– Child over 30 kg and adult: 500 to 750 mg/day in 2 divided doses or once daily if tolerated
– Maximum dose: 1000 mg daily
– Patient with severe renal impairment: 250 to 500 mg/day

Weight
(kg)

Daily dose
(mg)

250 mg
tablet

5

75-100

6

90-120

7

105-140

½ tab

8

120-160

½ tab

9

135-180

½ tab

10

150-200

½ tab

11

165-220

1 tab

12

180-240

1 tab

13

195-260

1 tab

14

210-280

1 tab

15

225-300

1 tab

16

240-320

1 tab

17

255-340

1 tab

18

270-360

1 tab

19

285-380

1½ tab

20

300-400

1½ tab

21

315-420

1 ½ tab

22

330-440

1½ tab

23

345-460

1½ tab

24

360-480

1½ tab

25

375-500

2 tab

26

390-520

2 tab

27

405-540

2 tab

28

420-560

2 tab

29

435-580

2 tab


30-35

500

2 tab

36-45

500

2 tab

46-55

750

3 tab

56-70

750

3 tab

> 70

1000

4 tab

Contra-indications, adverse effects, precautions

– Do not administer to patients with severe hepatic impairment.
– Administer with caution to patients with hepatic disease, diabetes mellitus or depression.
– May cause:
• frequent gastrointestinal disturbances (nausea, vomiting, gastritis, stomatitis, diarrhoea, abdominal pain, metallic taste, etc.);
• occasionally: endocrine disorders (hypothyroidism, gynecomastia, alopecia, etc.), hypoglycaemia, depression, anxiety, dizziness, hepatitis, peripheral or optic neuropathy, hypersensitivity reactions.
– For the management of adverse effects, see Appendix 10.
– Monitor combination with cycloserine (increased risk of seizure) and para-aminosalicylic acid (increased risk of hypothyroidism and gastrointestinal disturbances).
Pregnancy: avoid (potentially teratogenic)
Breast-feeding: may be used. Observe the infant for adverse effects.

Monitoring

– Symptomatic monitoring, liver and thyroid function

Patient instructions

– Take with food or at bedtime to limit gastrointestinal disturbances.
– Avoid alcohol during treatment.

Remarks

– To increase tolerance, start with a low dose (250 mg/day) then, increase the dose over 1 to 2 weeks to achieve the target dose.
– Ethionamide and prothionamide are used for the same indication at the same dosage.
 Storage: below 25°C -