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Table 2 Treatment guidelines for cystinosis

From: Cystinosis: a review

 

Medication

Daily dose

Frequency

Remarks

Symptomatic treatment

Renal Fanconi syndrome

Polyuria

 

Free water supply

Day and night

Special attention for sufficient hydration in case of fever, diarrhea and external heat

Early tube feeding may be needed for water requirements

Malnutrition

high caloric intake

130 % of RDI

 

Tube feeding can be needed in young infants

Renal salt loosing

sodium citrate or sodium bicarbonate

Oral 2–10 mmol/kg

QID

Between meals

Alkali losses

citrate or bicarbonate as sodium & potassium salts

Oral 5–15 mmol/kg

QID

Normal bicarbonate level (21–24 mmol/l) should be achieveda

Potassium losses

potassium citrate or potassium chloride

Oral 2–10 mmol/kg

QID

Potassium level > 3 mmol/l should be achieveda

Phosphate losses

sodium or potassium phosphate

Oral 30–60 mg elementary P/kg

QID

Normal age-related phosphate levels should be achieveda

High doses of phosphate supplements can cause or aggravate nephrocalcinosis

Treatment of rickets

calcidiol

Oral 10–25 μg

QD

Follow-up serum calcium concentration to prevent hypercalcemia

alpha-calcidol or calcitriol

Oral 0.04–0.08 μg/kg

Copper deficiency

copper supplementation

no data is available in cystinosis

 

1–10 mg/day depending on age and serum copper levels

Chlorophyllin tablets that are used to mitigate halitosis contain 4 mg of elemental copper per tablet

Difficult to control electrolyte losses and polyuria

indomethacin

Oral 1–3 mg/kg

BID

Follow-up serum creatinine

Discontinue in case of dehydration

Concomitant use with ACE inhibitors is contra-indicated

Carnitine losses

L- carnitine

Oral 20–50 mg/kg

TID

Not proven effect on clinically relevant muscle health

Proteinuria

ACE-inhibitors (enalapril)

Oral 0.10–0.25 mg/kg (for enalapril)

QD

Control serum creatinine and potassium administration at night to avoid hypotension complaints

Concomitant use with Indomethacin is contra-indicated

Hormonal substitution

Hypothyroidism

levothyroxin

Oral

QD

Start by 25 % of the recommended dose and increase to full dose in 4 weeks

<12 years:5 μg/kg

>12 years: 2–3 μg/kg

Adults: 1.7 μg/kg

Growth retardation

rhGH

SC 0.05 mg/kg

QD

Early initiation when growth failure persists after optimal control of feeding, electrolytes and rickets

Higher doses of phosphate supplementation may be needed

Glucose intolerance

insulin

SC (cfr endocrinology)

 

Control by blood glucose

Regular control of Hb A1C

Cysteamine treatment

Systemic administration

immediate release cysteamine bitartrate (Cystagon®)

1.30–1.95 g/m2

QID

Start at low dose (1/6 th of optimal dose), gradual increase over 6–8 weeks

delayed release cysteamine bitartrate (Procysbi®)

Start with 80 % of the immediate-release form

BID

Gastrointestinal complaints: add proton pomp inhibitors

Skin lesions (striae, molluscoid tumor at elbows): dose reduction by 25–50 %, control for copper deficiency

Regular dosing of WBC cystine levels (children x4 per year, adults x1-2 per year)b

Corneal cystine crystals

cysteamine eye drops 0.5 %

topical application

8–10 time daily

Yearly eye examination

cysteamine eye gel (Cystadrops®)

QID

Varia

Gastro-intestinal complaints

Proton pump inhibitors omeprazole

<10 kg: 1- mg/kg

BID

 

10–20 kg: 10–20 mg

BID

>20 kg: 20–40 mg

BID

  1. aTrough levels of electrolytes and phosphate (before the administration of the next dose) should be measured
  2. bBlood for the determination of WBC cystine levels should be taken 6 h after Cystagon® and 12 h after Procysbi® administration