Altered mental function during intravenous infusion of recombinant human insulin-like growth factor 1

Recombinant human insulin-like growth factor-1 (rhIGF-1) is currently used experimentally to treat patients with insulin-resistant diabetes mellitus, impaired growth, protein malnutrition, and osteoporosis. We report here the case of a marked transient alteration in consciousness in a healthy 22-year-old man who was given an IV infusion of a relatively low dose of rhIGF-1 for 1 hour. This individual developed the sudden onset of dizziness, nausea, coldness, air hunger, and pallor. He became unresponsive to simple questions and experienced diaphoresis, a feeling of warmth, and paresthesias. Although there was a mild fall in heart rate and blood pressure, these hemodynamic effects did not appear sufficient to cause the altered mentation. There were no changes in serum glucose, phosphorus, or potassium that could seem to account for these events. This individual recovered completely several minutes after stopping the rhIGF-1 infusion.