A system providing for user intervention in a medical control arrangement may comprise a first user intervention mechanism responsive to user selection thereof to produce a first user intervention signal, a second user intervention mechanism responsive to user selection thereof to produce a second user intervention signal, and a processor executing a drug delivery algorithm forming part of the medical control arrangement. The processor may be responsive to the first user intervention signal to include an intervention therapy value in the execution of the drug delivery algorithm, and responsive to the second user intervention signal to exclude the intervention therapy value from the execution of the drug delivery algorithm. The medical control arrangement may be a diabetes control arrangement, the drug delivery algorithm may be an insulin delivery algorithm, and the intervention therapy value may be, for example, an intervention insulin quantity or an intervention carbohydrate quantity.
