Burget DW, Chiverton SG, Hunt RH Is there an optimal degree of acid suppression for healing of duodenal ulcers? A model of the relationship between ulcer healing and acid suppression. Gastroenterology. 1990 Aug;99(2):345-51.
DeVault KR, Castell DO Updated guidelines for the diagnosis and treatment of gastroesophageal reflux disease. The Practice Parameters Committee of the American College of Gastroenterology. Am J Gastroenterol. 1999 Jun;94(6):1434-42.
Katz PO, Castell DO, Chen Y, Andersson T, Sostek MB Intragastric acid suppression and pharmacokinetics of twice-daily esomeprazole: a randomized, three-way crossover study. Aliment Pharmacol Ther. 2004 Aug 15;20(4):399-406.
Kromer W, Horbach S, Lühmann R Relative efficacies of gastric proton pump inhibitors: their clinical and pharmacological basis. Pharmacology. 1999 Aug;59(2):57-77. Review.
Revicki DA, Crawley JA, Zodet MW, Levine DS, Joelsson BO Complete resolution of heartburn symptoms and health-related quality of life in patients with gastro-oesophageal reflux disease. Aliment Pharmacol Ther. 1999 Dec;13(12):1621-30.
Stedman CA, Barclay ML Review article: comparison of the pharmacokinetics, acid suppression and efficacy of proton pump inhibitors. Aliment Pharmacol Ther. 2000 Aug;14(8):963-78. Review.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.