Drug interactions between proton pump inhibitors and antiretroviral drugs

Development of stable amorphous solid dispersion and quantification of crystalline fraction of lopinavir by spectroscopic-chemometric methods

This study aimed to improve the dissolution of the poorly soluble drug lopinavir (LPV) by preparing amorphous solid dispersions (ASDs) using solvent evaporation method. The ASD formulations were prepared with ternary mixtures of LPV, Eudragit® E100, and microcrystalline cellulose (MCC) at various weight ratios. The ASDs were subjected to solid-state characterization and in vitro drug dissolution testing. Chemometric models based on near infrared spectroscopy (NIR) and NIR-hyperspectroscopy (NIR-H) data were developed using the partial least squares (PLS) regression and externally validated to estimate the percent of the crystalline LPV in the ASD. Initially, the solid-state characterization data of ASDs showed transformation of the drug from crystalline to amorphous. Negligible fraction of crystalline LPV was present in the ASD (3%). Compared to pure LPV, ASDs showed faster and higher drug dissolution (<2% vs. 60.3-73.5%) in the first 15 min of testing. The ASD was stable against crystallization during stability testing at 40 °C/75% for a month. In conclusion, the prepared ASD was stable against devitrification and enhance the dissolution of LPV.

Management of gastroesophageal reflux disease in adults: a pharmacist's perspective

Gastroesophageal reflux disease (GERD) is a common gastrointestinal diagnosis, a leading reason for endoscopy and cause of potentially serious complications, resulting in significant individual and system-wide health burden. Approximately one quarter of people living in western countries have experienced GERD, and the prevalence appears to be on the rise. Risk factors for GERD include hiatus hernia, obesity, high-fat diet, tobacco smoking, alcohol consumption, pregnancy, genetics, and some medications. The cardinal symptoms of GERD are troublesome heartburn and regurgitation. GERD is identified by taking a patient-centered history and if necessary can be classified by endoscopic investigation. The role of the pharmacist in the management of GERD is to confirm the diagnosis by history taking, confirm there are no alarming signs or symptoms that require referral to a doctor, and recommendation of short-term therapy to control symptoms. Effective pharmacological treatments for GERD include antacids, alginate, histamine H2 receptor antagonists, and proton pump inhibitors. This narrative review includes a comparison of the efficacy and safety of these treatments and pertinent information to help pharmacists advise patients with GERD on their appropriate use.

Upper Gastrointestinal Symptoms Predictive of Candida Esophagitis and Erosive Esophagitis in HIV and Non-HIV Patients: An Endoscopy-Based Cross-Sectional Study of 6011 Patients

Upper gastrointestinal (GI) symptoms are common in both HIV and non-HIV-infected patients, but the difference of GI symptom severity between 2 groups remains unknown. Candida esophagitis and erosive esophagitis, 2 major types of esophagitis, are seen in both HIV and non-HIV-infected patients, but differences in GI symptoms that are predictive of esophagitis between 2 groups remain unknown. We aimed to determine whether GI symptoms differ between HIV-infected and non-HIV-infected patients, and identify specific symptoms of candida esophagitis and erosive esophagitis between 2 groups.We prospectively enrolled 6011 patients (HIV, 430; non-HIV, 5581) who underwent endoscopy and completed questionnaires. Nine upper GI symptoms (epigastric pain, heartburn, acid regurgitation, hunger cramps, nausea, early satiety, belching, dysphagia, and odynophagia) were evaluated using a 7-point Likert scale. Associations between esophagitis and symptoms were analyzed by the multivariate logistic regression model adjusted for age, sex, and proton pump inhibitors.Endoscopy revealed GI-organic diseases in 33.4% (2010/6.011) of patients. The prevalence of candida esophagitis and erosive esophagitis was 11.2% and 12.1% in HIV-infected patients, respectively, whereas it was 2.9% and 10.7 % in non-HIV-infected patients, respectively. After excluding GI-organic diseases, HIV-infected patients had significantly (P < 0.05) higher symptom scores for heartburn, hunger cramps, nausea, early satiety, belching, dysphagia, and odynophagia than non-HIV-infected patients. In HIV-infected patients, any symptom was not significantly associated with CD4 cell count. In multivariate analysis, none of the 9 GI symptoms were associated with candida esophagitis in HIV-infected patients, whereas dysphagia and odynophagia were independently (P < 0.05) associated with candida esophagitis in non-HIV-infected patients. However, heartburn and acid regurgitation were independently (P < 0.05) associated with erosive esophagitis in both patient groups. The internal consistency test using Cronbach's α revealed that the 9 symptom scores were reliable in both HIV (α, 0.86) and non-HIV-infected patients (α, 0.85).This large-scale endoscopy-based study showed that HIV-infected patients have greater GI symptom scores compared with non-HIV-infected patients even after excluding GI-organic diseases. None of the upper GI symptoms predict candida esophagitis in HIV-infected patients, but dysphagia and odynophagia predict candida esophagitis in non-HIV-infected patients. Heartburn and acid regurgitation predict erosive esophagitis in both patient groups.

Drug interactions and antiretroviral drug monitoring

Owing to the improved longevity afforded by combination antiretroviral therapy (cART), HIV-infected individuals are developing several non-AIDS-related comorbid conditions. Consequently, medical management of the HIV-infected population is increasingly complex, with a growing list of potential drug-drug interactions (DDIs). This article reviews some of the most relevant and emerging potential interactions between antiretroviral medications and other agents. The most common DDIs are those involving protease inhibitors or non-nucleoside reverse transcriptase inhibitors, which alter the cytochrome P450 enzyme system and/or drug transporters such as p-glycoprotein. Of note are the new agents for the treatment of chronic hepatitis C virus infection. These new classes of drugs and others drugs that are increasingly used in this patient population represent a significant challenge with regard to achieving the goals of effective HIV suppression and minimization of drug-related toxicities. Awareness of DDIs and a multidisciplinary approach are imperative in reaching these goals.

Drug interactions of new antiretroviral drugs

A systematic review was made of the drug interactions of new antiretroviral drugs. In order to do this a search was made in Pubmed to find articles published from January 2007 to September 2009 and the full-text articles which contained information about new antiretroviral drugs were selected. This search was then complemented with information from the technical specifications of the drugs and consultations made on webpages specialized in antiretroviral interactions: www.interaccioneshiv.com and www.hiv-druginteractions.org. The information about the possible interactions of new antiretroviral drugs with one another and with the therapeutic groups which are most widely used in patients infected with the human immunodeficiency virus was analyzed.

Esomeprazole for the treatment of peptic ulcer bleeding

Peptic ulcer bleeding is the most common cause of acute bleeding in the upper GI tract. The incidence of peptic ulcer bleeding has slowly decreased and endoscopic treatment options have improved; nevertheless, it remains a very common condition with a 7-15% mortality. Acidic environments have a negative effect on hemostasis. Therefore, acid inhibitors have been applied in the adjuvant treatment of peptic ulcer bleeding, both in preventing rebleeding and in treating the underlying cause. This requires profound acid suppressive therapy aiming for a rapid onset of effect and a persistent intragastric pH above 6. This can only be achieved by proton pump inhibitors (PPIs). Esomeprazole is the S-isomer of omeprazole, and the first PPI to consist of only the active isomer. A number of studies have compared esomeprazole with other PPIs, demonstrating a faster and more persistent increase in intragastric pH with the use of esomeprazole than with other agents. Continuous high-dose intravenous treatment with esomeprazole decreases rebleeding, surgery, transfusion rates and hospital days in peptic ulcer bleeding.

The pharmacology of esomeprazole and its role in gastric acid related diseases

Esomeprazole (S-isomer of omeprazole) demonstrates a better pharmacokinetic/pharmacodynamic profile than the racemic product omeprazole. Esomeprazole's pharmacological activity of gastric acid secretion is through proton pump inhibition. The pharmacokinetic properties provide for an enhanced pharmacological effect. Esomeprazole is rapidly absorbed and the extent of absorption is higher resulting in higher systemic absorption of esomeprazole (bioavailability), which coupled with reduced clearance results in greater systemic exposure. This pharmacodynamic profile then provides for a prolongation of inhibition of gastric acid output and correlates well with its more beneficial therapeutic efficacy over omeprazole and some of the other proton-pump inhibitors. It has been well proven as an effective agent in the treatment of gastro-esophagitis reflux disease, (reflux esophagitis and non-erosive reflux disease), NSAID-induced gastric-intestinal symptoms and ulcers, Helicobacter pylori infection and Zollinger-Ellison syndrome. Esomeprazole has a good tolerability profile and a low potential for drug interaction.

Esomeprazole: a proton pump inhibitor

Proton pump inhibitors (PPIs) are the most potent inhibitors of gastric acid secretion available, and they are effective for treating all acid-related disorders. Esomeprazole is one of several most recent PPIs that became available to the market in 2001. Esomeprazole is indicated for the treatment of gastroesophageal reflux disease in adults and children, risk reduction of NSAIDs-associated gastric ulcer, Helicobacter pylori eradication and control of pathological hypersecretory conditions associated with Zollinger-Ellison syndrome. Esomeprazole is available in both oral and intravenous formulations. A number of studies have compared esomeprazole with other PPIs. While differences supporting esomeprazole have been reported, the magnitude of differences has been variable and of uncertain clinical importance. Cost plays a major role in prescribing patterns of PPIs.