What are some of the arguments made against euthanasia?

Answers can include the following: (1) mistake in diagnosis; (2) difficulty in determining if euthanasia is voluntary, for example, when there is an undue influence exerted on the patient by a member of the family or beneficiary of a will for financial reasons; (3) slippery slope argument, for example, with the growth of managed care there may be more pressure to hasten death for those who are elderly, uneducated, on welfare, or disabled; (4) altering the role of physicians to include the practice of killing patients would bring about a psychological upheaval in the doctor–patient relationship, and patients would become less trustful of their physician's role as healer.