We wish to point out several serious flaws in the design, methodology, and interpretation of the study reported by Slugg and Haug in the November 1992 issue of the Archives,1 regarding central nervous system (CNS) adverse reactions (ADRs) with ranitidine. While it is acknowledged that ranitidine is associated with rare reports of CNS adverse events (including malaise, dizziness, somnolence, insomnia, vertigo, mental confusion, agitation, depression, hallucinations, blurred vision, and involuntary motor disturbances), these are most often seen in the setting of renal or hepatic impairment among severely ill hospitalized patients, when multiple factors may be involved in their causation. Collectively, CNS-ADRs have occurred in fewer than 0.1% of patients receiving ranitidine in controlled clinical trials (data on file, Glaxo Inc, Research Triangle Park, NC).
Several aspects of the study design are likely to have introduced bias. Although prospective, the study does not attempt to test a stated hypothesis nor
McIsaac RL, Koch KM, Lewis JH. Ranitidine Pharmacokinetics and Central Nervous System. Arch Intern Med. 1994;154(3):342-343. doi:10.1001/archinte.1994.00420030158017