medwireNews: Cyproheptadine hydrochloride may have beneficial effects on growth that are unrelated to its influence on appetite in children with growth hormone (GH) insensitivity syndrome, report researchers.

Maryam Razzaghy-Azar (Iran University of Medical Sciences, Tehran) and co-workers tested the medication in 15 such patients, following an experience in which they prescribed it to a patient purely as an appetite stimulant, but noted an unexpected increase in his height. GH insensitivity syndrome is normally responsive only to treatment with recombinant human insulin-like growth factor (IGF)-I therapy.

The patients all had classical GH insensitivity syndrome – they had high basal GH and low IGF-I levels, and no growth response to exogenous GH. They presented between the ages of 1 and 8 years, and were observed for between approximately 1 and 4 years before starting on cyproheptadine hydrochloride. This they received for between 3 months and 8.1 years, at a daily dose of 0.25 mg/kg, divided into three doses every 8 hours.

For all 15 patients, the average height standard deviation score (SDS) fell from –6.4 to –7.0 during the observation period, but improved again to –6.0 with treatment. Height velocity improved from 1.8 to 6.1 cm/year (compared with 2.2 cm/year in five untreated controls), but there was no effect on the children’s BMI.

Four patients took cyproheptadine hydrochloride for at least 30 months, receiving it from between the ages of 2.1 and 10.2 years, and taking it for between 2.7 and 8.1 years. Their height SDS fell from –5.3 to –5.9 during observation but rose from –6.2 to –3.7 during treatment.

Such an effect makes treatment with cyproheptadine hydrochloride “comparable to IGF-I therapy”, write the researchers in Clinical Endocrinology.

They note that recombinant human IGF-I “is expensive and not registered for reimbursement in some countries especially those with low and middle income, whereas cyproheptadine would be inexpensive and widely available.”

Some patients reported increased appetite during treatment, but others did not. Some reported sleepiness during the first week of treatment, but this then improved, and the team generally found no adverse clinical or biochemical effects during follow-up.

Levels of IGF-I slightly increased during treatment, but remained below the normal range, so the researchers believe this did not underlie cyproheptadine hydrochloride’s apparent growth effects. They suggest the drug “may be involved in a pathway that needs to be further investigated with molecular studies.”

Eleanor McDermid

Clin Endocrinol 2018; Advance online publication

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