Clues to role:
(1) onset of delirium after drug started
(2) onset of delirium after dose increased
(3) onset of delirium after introducing a drug that interferes with metabolism
(4) onset of disease (such as renal failure) that interferes with drug elimination
High risk agents:
(1) drugs with anticholinergic properties (see below)
(2) sedative hypnotics (benzodiazepines)
(3) narcotics, including codeine
(4) dopaminergic agents (antiparkisonian agents such as L-dopa)
(5) corticosteroids
(6) lithium
Drugs with anticholinergic properties (Burns et al, Ellenhorn):
(1) H2-blockers (cimetidine, ranitidine)
(2) prednisolone
(3) theophylline, aminophylline
(4) tricyclic antidepressants
(5) digoxin
(6) calcium-channel blockers (nifedipine)
(7) antipsychotic agents (chlorpromazine, or other phenothiazines, haloperidol)
(8) diuretics (furosemide, thiazides)
(10) isosorbide dinitrate
(11) warfarin
(12) dipyridamole
(13) ACE inhibitors (captopril)
(14) belladonna alkaloids (atropine, scopolamine, cyclopentolate, tropicamide)
(15) antihistamines (chlorpheniramine, diphenhydramine, promethazine, orphenadrine)
(16) antispasmodics for irritable bowel syndrome (methantheline, propantheline)
Moderate risk agents:
(1) alpha-blockers
(2) lidocaine
(3) beta-blockers
(4) NSAIDS
(5) laxatives
Low risk agents:
(1) antibiotics
(2) anticonvulsants
