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In general, Dignitas uses the following protocol to assist suicides: an oral dose of an antiemetic drug, followed approximately 1 hour later by a lethal overdose of powdered pentobarbital dissolved in a glass of water or fruit juice. If necessary, the drugs can be ingested via a drinking straw. The pentobarbital overdose depresses the central nervous system, causing the person to become drowsy and fall asleep within 5 minutes of drinking it. Anaesthesia progresses to coma as the person's breathing becomes more shallow, followed by respiratory arrest and death, which occurs within 30 minutes of ingesting the pentobarbital.
In a few cases in 2008, Dignitas used breathing helium gas[4] as a suicide method instead of a pentobarbital overdose. This avoids the need for medical supervision and prescription controlled drugs, and is therefore cheaper and more available.[5]//