Cycloserine (Cs)

Therapeutic action

– Antibacterial with bacteriostatic activity

Presentation

– 250 mg capsule

Dosage

– Child under 30 kg: 10 to 20 mg/kg/day in 2 divided doses, or once daily depending on available formulation and tolerance
– Child over 30 kg and adult: 500 to 750 mg/day in 2 divided doses; some patients may tolerate once daily dosing.
– Maximum dose: 1000 mg daily
– Patients with severe renal impairment: 250 mg once daily or 500 mg/dose, 3 times per week

Weight
(kg)

Daily dose
(mg)

250 mg
capsule

5

50-100

6

60-120

7

70-140

8

80-160

9

90-180

10

100-200

11

110-220

12

120-240

13

130-260

1 caps

14

140-280

1 caps

15

150-300

1 caps

16

160-320

1 caps

17

170-340

1 caps

18

180-360

1 caps

19

190-380

1 caps

20

200-400

1 caps

21

210-420

1 caps

22

220-440

1 caps

23

230-460

1 caps

24

240-480

1 caps

25

250-500

1 caps

26

260-520

1 caps x 2

27

270-540

1 caps x 2

28

280-560

1 caps x 2

29

290-580

1 caps x 2


30-35

500

1 caps x 2

36-45

500

1 caps x 2

46-55

500

1 caps x 2

56-70

750

1 caps (morning) + 2 caps (evening)

> 70

750

1 caps (morning) + 2 caps (evening)

Contra-indications, adverse effects, precautions

– Avoid if possible in patients with epilepsy, depression, psychosis, severe anxiety, history of neurological or psychiatric disorders, alcohol dependence. However, if cycloserine is essential to the regimen, it can be administered under close monitoring.
– Administer with caution to patients with renal impairment.
– May cause:
• neurotoxic effects: seizure, headache, lethargy, confusion, personality change, dizziness, drowsiness, anxiety, psychosis, depression, suicidal ideation; rarely, peripheral neuropathy.
• hypersensitivity reactions.
– For the management of adverse effects, see Appendix 10.
– Avoid or monitor combination with isoniazid, ethionamide, prothionamide (increased risk of neurotoxic effects).
– Administer concomitantly pyridoxine (vitamin B6) to prevent neurotoxic effects (child: 5 to 10 mg/day; adult: 50 mg per 250 mg of cycloserine/day).
Pregnancy: safety is not established, no known teratogenicity. To prevent neurotoxic effects, administer pyridoxine as above.
Breast-feeding: no contra-indication. To prevent neurotoxic effects, administer pyridoxine as above. Supplement the breast-fed infant with pyridoxine (5 mg/day).

Monitoring

– Symptomatic monitoring, in particular early detection of depression and behaviour changes

Patient instructions

– Take capsules with water before or after meals.
– 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.
 Storage: below 25°C -