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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