Sodium perchlorate

Concomitant administration of iodine (e.g. iodine-containing medicines or radiographic contrast agents, perioperative use of high-dose iodide) reduces the effect of sodium perchlorate.

Concomitant administration of thiamazole causes a positive perchlorate discharge test (even in patients with hyperthyroidism and healthy subjects) as a result of inhibition of iodine organification.

Sodium perchlorate should not be taken during pregnancy, as insufficient experience is available regarding a possible risk to the unborn child. Sodium perchlorate crosses the placenta to the fetus unhindered. The fetal thyroid gland may react more sensitively to antithyroid drugs than an adult thyroid.

No studies are available on secretion of sodium perchlorate in breast milk. If treatment with sodium perchlorate is necessary during lactation, breast-feeding should be ceased.

None known.

Evaluation of undesirable effects is based on the following frequencies: common (≥1% to <10%), uncommon (≥0.1% to <1%), rare (≥0.01% to <0.1%), very rare (<0.01% or unknown).

The occurrence of undesirable effects is dose-dependent.

Common (≥1% to <10%):

• transient rash,
• nausea or retching,
• dry mouth, pharyngeal irritation,
• lymphadenopathy,
• leukopenia,
• purpura,
• febrile arthralgia,
• drug fever.

Uncommon (≥0.1% to <1%):

• initial diarrhoea,
• mild muscle cramps,
• burning in the feet,
• heavy-headedness,
• eosinophilia,
• pruritus,
• jaundice.

An uncommon occurrence is agranulocytosis, which usually resolves rapidly and without sequelae on discontinuing sodium perchlorate drops.

Very rare (<0.01%):

• agranulocytosis with a fatal outcome,
• thrombocytopenia or aplastic anaemia with a fatal outcome (incidence approximately 0.1%),
• minimal albuminuria,
• nephrotic syndrome, partially or fully reversible,
• hair loss,
• acne,
• generalised dermatitis,
• urticaria,
• liver damage with acute liver failure,
• erythema nodosum with febrile episodes, antinuclear and anti-erythrocyte antibodies and eosinophilia,
• perforation of a duodenal ulcer.

These extremely rare changes have usually been observed during ongoing treatment with perchlorate, although a causal association could not be proven.