Severe neurotoxicity (SN) has been reported in adult liver transplant (tx) pts treated with FK506. Adult renal tx pts may have less SN, but the presence of SN and mild neurotoxicity (MN) in pediatric renal tx pts is not well described. We evaluated SN and MN in pediatric renal tx recipients on FK506.

All pediatric renal tx pts treated with FK506 at our institution were evaluated (14 pts, aged 9y-22y). Chart review determined occurrence of SN(delirium, seizures, dysarthria, and coma). MN was measured by pt survey. Mean time on FK506 was 7.3 mo (2 mo-13 mo) and mean time since tx was 27 mo (2 mo-14 y). All pts received po FK506 (0.3 mg/kg/day) with levels between 5 and 12 ng/ml as measured by automated microparticle enzyme immunoassay (IMx, Abbott Laboratories).

SN: 1 pt (7%) experienced seizures associated with malignant hypertension. This pt has remained on FK506 without further seizures. No other episodes of SN were documented. MN: 14/14 (100%) pts completed the survey. 7/14 (50%) reported at least 1 symptom “most of the time” and 4/14 (29%) reported at least 1 “all of the time”. The most common complaint was myalgias (7/14, 50%) followed by tremors (7/14, 50%), fatigue (5/14, 38%), hyperesthesias (4/14, 28%),headache (2/14, 14%), insomnia (2/14, 14%), pruritus (2/14, 14%), and photophobia (2/14,14%).

SN is relatively uncommon in pediatric renal tx pts treated with FK506. MN may be more common and should be anticipated.