• Assessment of pharmacokinetic parameters of once daily subcutaneously administered methylnaltrexone in 10 evaluable neurointensive care patients.
• Quantification of methylnaltrexone passage through the blood-brain-barrier in critically ill patients with severe cerebral affections.
• Observation of laxation response after methylnaltrexone application and relation to plasma concentrations of methylnaltrexone.
• Assessing the safety of once daily administered methylnaltrexone in neurointensive care patients.
• Trial with medicinal product

After administration of methylnaltrexone s.c. multiple peripheral blood samples and additionally two liquor samples are drawn during a dose interval on day 1, 3, and 5 of drug administration.

Inclusion criteria:

• hospitalisation in the neurointensive care unit
• deep sedation with sufentanil doses of = 40 mcg/h
• male or female aged 18 years or older
• females: negative pregnancy test
• Ventricular drainage as part of needed therapeutic measures

Exclusion criteria:

• History of hypersensitivity to methylnaltrexone (Relistor®)
• confirmed or suspected obstructive ileus or factors possibly leading to intestinal obstruction (e.g. an intestinal tumor)
• increased risk for patients with localized or diffused reduction in structural integrity of the gastrointestinal tract (e.g. peptic ulcer, acute diverticulitis)
• severe hepatic insufficiency (Child-Pugh Class C)
• renal impairment (glomerular filtration rate < 90 ml/min) with or without renal replacement therapy
• severe diarrhea despite high opioid dosing
• participation in another study with an investigational drug within the 30 days preceding and during the present study