Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ranitidine was first marketed in 1981; since then many patients have been treated such that much experience has been accumulated on the safety of this histamine H2-receptor antagonist in the treatment of gastroduodenal disease. A wide array of ranitidine-associated side effects has been described, but infrequently. As so much information is now available, the aim of this review is to assess the weight of evidence for a causal link between ranitidine and the reported side effects. Overall, ranitidine is well tolerated. The incidence of general side effects at less than 2% is very similar to placebo. Headaches, tiredness, dizziness and mild gastrointestinal disturbance (e.g. diarrhoea, constipation and nausea) are among the most frequent complaints, but have very seldom resulted in stopping treatment. Cardiovascular side effects are extremely rare and unpredictable with the usual doses of oral ranitidine (at most 1 in 1 million patients). They mostly comprise sinusal bradycardia and atrioventricular blockade, especially after rapid intravenous administration, receding after cessation of the drug. Clinical studies, however, have not shown a significant pharmacological effect of ranitidine on the cardiovascular system via H2-receptors, even though individual sensitivities cannot be ruled out in a few isolated reports. Ranitidine is unlikely to be directly hepatotoxic: a transient change in liver function tests has been noted in only 1 in 100 to 1 in 1000 patients. Several cases of mixed hepatitis have been reported, but very few were fully documented. The incidence of ranitidine-associated acute hepatitis has been estimated to be less than 1 in 100,000 patients. Neuropsychiatric complications may be less common and clinically quite similar to those reported with cimetidine, i.e. confusion, disorientation, hallucinations, delirium. These side effects have occurred especially in critically ill and multiple-therapy patients, or patients with chronic renal or hepatic failure, so that the direct causal link with ranitidine treatment was often difficult to ascertain. Even though an H2-receptor-mediated effect is an attractive hypothesis (since similar complications were noted with other H2-receptor antagonists), other mechanisms have been suggested to play a role, e.g. cholinergic or histaminic effects. The overall incidence of neuropsychiatric complications is probably markedly less than 1%. White cell injury (i.e. agranulocytosis) appears to be the most frequent haematological complication, even though case reports are very few and poorly documented.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Side effects of ranitidine. 204 87

The authors conducted a retrospective review of 21 United States trials of ranitidine in acid peptic diseases and compared the adverse events in elderly (> or = 65 years) and nonelderly (< 65 years) patients. Ranitidine dosages ranged from 150 mg/day to 300 mg twice daily for treatment periods of 4 to 52 weeks. Of the 4041 patients included in this review, 402 elderly and 2188 nonelderly patients received ranitidine and 245 elderly and 1206 nonelderly patients received placebo; 29%, 29%, 32%, and 26% of these patients, respectively, reported some type of adverse event. When only drug-related adverse events (as judged by the investigators under blinded conditions) were evaluated, these percentages dropped to 2%, 2%, and 1% and 2%, respectively. Gastrointestinal adverse events (e.g., nausea and diarrhea) and central nervous system adverse events (e.g., headache and dizziness) were the most common (0.7% and 0.8%, respectively), with comparable incidence rates in the elderly and nonelderly patients. The authors conclude that ranitidine is as safe in elderly patients as it is in nonelderly patients. No difference in the incidence of adverse events was found between older and younger patients who received ranitidine or placebo.
 ...
PMID:The safety of ranitidine in elderly versus non-elderly patients. 842 19