<p>Patient with cardiac decompensation, chronic alcoholic or acutely alcohol-intoxicated patients, pre-anaesth elevated CSF pressure, globe injuries, increased intraocular pressure (e.g. glaucoma), neurotic traits or psychiatric illness (e.g. schizophrenia, acute psychosis), acute intermittent porphyria, seizures, hyperthyroidism, pulmonary or upper resp infection, intracranial mass lesions, head injury, or hydrocephalus, hypovolaemia, dehydration, cardiac disease esp coronary artery disease (e.g. CHF, myocardial ischaemia, MI). Pregnancy and lactation.</p>