Because of the potential risk of toxicity from the large amount of the excipient propylene glycol, Agenerase oral solution is contraindicated in infants and children below the age of 4 years, pregnant women, patients with hepatic impairment or failure, patients with renal failure, and patients treated with disulfiram or metronidazole or preparations that contain alcohol (e.g. ritonavir oral solution) or additional propylene glycol (see also Take special care with Agenerase).