Effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality: A clinical observation study

AIM

To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality.

METHODS

Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly allocated to the combination therapy group or monotherapy group. The former received hydrotalcite combined with esomeprazole, and the latter received esomeprazole alone, for 8 wk. Twenty-four healthy volunteers were recruited and acted as the healthy control group. Endoscopic ulcer healing was observed using white light endoscopy and narrow band imaging magnifying endoscopy. The composition of collagen fibers, amount of collagen deposition, expression of factor VIII and TGF-β1, and hydroxyproline content were analyzed by Masson staining, immunohistochemistry, immunofluorescent imaging and ELISA.

RESULTS

Following treatment, changes in the gastric microvascular network were statistically different between the combination therapy group and the monotherapy group (P < 0.05). There were significant differences (P < 0.05) in collagen deposition, expression level of Factor VIII and TGF-β1, and hydroxyproline content in the two treatment groups compared with the healthy control group. These parameters in the combination therapy group were significantly higher than in the monotherapy group (P < 0.05). The ratio of collagen I to collagen III was statistically different among the three groups, and was significantly higher in the combination therapy group than in the monotherapy group (P < 0.05).

CONCLUSION

Hydrotalcite combined with esomeprazole is superior to esomeprazole alone in improving gastric ulcer healing quality in terms of improving microvascular morphology, degree of structure maturity and function of regenerated mucosa.

Survey of topical oral solutions for the treatment of chemo-induced oral mucositis

Purpose. The objectives of this study were (1) to describe the usage of topical oral solutions in patients experiencing chemotherapy-induced oral mucositis (CIOM); and (2) to survey the care of oral mucositis provided to patients by clinical oncology pharmacists in institutional settings.

Methods. Surveys were distributed to institutional pharmacists in the US, who were asked to provide the components of their ‘magic mouthwash’. Other questions included whether an institutional mucositis management guideline is available and what is the involvement of clinical pharmacy in mucositis care.

Results. Forty institutions returned surveys during the study period. The top five ingredients used to compound the magic mouthwash are diphenhydramine, viscous lidocaine, magnesium hydroxide/aluminum hydroxide, nystatin and corticosteroids. Most institutions administer the mouthwash every 4 hours (36%) or every 6 hours (36%). Of the surveyed institutions, 33% currently possess guidelines for the management of CIOM.

Conclusions. Most institutions in the country formulate their topical solution, or magic mouthwash, with a variety of ingredients. There is a need to standardize the ingredients used to compound the magic mouthwash, in order to fully evaluate the efficacy of the solution to manage CIOM.

Nanoadduct relieves: Alleviation of developmental toxicity of Cr(VI) due to its spontaneous adsorption to Mg(OH)2 nanoflakes

During pregnancy, both the mother and fetus are vulnerable to environmental pollution by particulate matters and chemicals. Although the toxicity of free pollutants has been frequently reported, the impact of nanoparticle/pollutant adducts on the vulnerable pregnant population remains unclear. In this study, pregnant mice were orally exposed to Mg(OH)2 nanoflakes and nanoflakes adsorbed with Cr(VI) anions during the peri-implantation and organogenesis stages of pregnancy at doses that did not induce systemic toxicity or pregnancy complications. The nano-Mg(OH)2/Cr(VI) adducts formation reduced fetal developmental toxicity compared with the toxicity induced by the same concentration of free Cr(VI) anions.

[The development of severe methemoglobinemia in patients receiving "Almagel A"]

This clinical case and the literature review show possible development of methemoglobinemia due to the use of local anesthetics, included in drugs for the gastrointestinal diseases treatment, in particular benzocaine, which is the methaemoglobin forming agent. These drugs are common and often taken by the patients themselves without any control. The aim of our paper is to draw the attention of physicians to the risk of the widely known drug administration which can be purchased without a prescription.

The carry-over effect on the bowel habit in elderly long-term patients of long-term bulk-forming products containing stimulant laxative

This study was undertaken to investigate the possible carry-over effect on elderly long-term patients of bulk-forming products containing stimulant type laxatives. Thirty-six patients received magnesium hydroxide daily for a mean period of 10 months prior to the study, and 23 patients received bulk laxatives containing cassiae senna daily for a mean period of 13 months prior to the study. The pre-study laxatives were randomly changed either to magnesium hydroxide or to bulk laxatives. In the patient group receiving a bulk-forming product containing stimulant type laxative long-term prior to the study, the need for additional stimulant laxatives during the pure bulk laxative (3.0 vs. 3.8/4 weeks, NS) or magnesium hydroxide treatment (2.6 vs. 2.7/4 weeks, NS) was not more frequent and the frequency of defaecation was not lower than in the patients (during bulk laxative 11.2 vs. 9.3/4 weeks, NS and during magnesium hydroxide 12.0 vs. 13.7/4 weeks, NS) who received long-term magnesium hydroxide treatment prior to the study. Thus, our data indicated no carry-over effect after the use of bulk-forming laxatives containing senna for 13 months in elderly long-term patients.

The effect of a combination antacid preparation containing aluminium hydroxide and magnesium hydroxide on rosuvastatin pharmacokinetics

OBJECTIVE

Rosuvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor used for the treatment of dyslipidaemia, may be co-administered with antacids in clinical practice. This trial assessed the effect of simultaneous and separated administration of an antacid preparation containing aluminium hydroxide 220 mg/5 mL and magnesium hydroxide 195 mg/5 mL (co-magaldrox 195/220) on the pharmacokinetics of rosuvastatin.

RESEARCH DESIGN AND METHODS

A randomised, open-label, three-way crossover trial was performed. Healthy male volunteers (n = 14) received a single dose of rosuvastatin 40 mg alone, rosuvastatin 40 mg plus 20 mL antacid suspension taken simultaneously, and rosuvastatin 40 mg plus 20 mL antacid suspension taken 2 h after rosuvastatin on three separate occasions with a washout of > or = 7 days between each.

MAIN OUTCOME MEASURES

The primary parameters were area under the rosuvastatin plasma concentration-time curve from time zero to the last quantifiable concentration (AUC(0-t)) and maximum observed rosuvastatin plasma concentration (C(max)) in the absence and presence of antacid.

RESULTS

When rosuvastatin and antacid were given simultaneously, the antacid reduced the rosuvastatin AUC(0-t) by 54% (90% confidence interval [CI] for the treatment 0.40-0.53) and C(max) by 50% (90% CI 0.41-0.60). When the antacid was given 2 h after rosuvastatin, the antacid reduced the rosuvastatin AUC(0-t) by 22% (90% CI 0.68-0.90) and the C(max) by 16% (90% CI 0.70-1.01). The effect of repeated antacid administration was not studied and it cannot be discounted that this may have resulted in a stronger interaction than that observed here.

CONCLUSIONS

Simultaneous dosing with rosuvastatin and antacid resulted in a decrease in rosuvastatin systemic exposure of approximately 50%. This effect was mitigated when antacid was administered 2 h after rosuvastatin.

[Successful treatment of hemorrhagic cystitis after radiation therapy with intravesical instillation of aluminium hydroxide gel and magnesium hydroxide: report of a case]

A 77-year-old man was admitted to our hospital due to macrohematuria and bladder tamponade. Bladder hemorrhage caused by radiation therapy had not improved after bladder lavage, intravesical drip infusion, medication of hemostatics, and transurethral coagulation. Bladder hemorrhage had completely disappeared 7 days after the intravesical instillation of 50-100 ml aluminium hydroxide gel and magnesium hydroxide for an hour per day. This method is easy and can be performed without complications. This method might be useful as first-line therapy in the case of severe bladder hemorrhage.

Comparison of two antacid preparations on intragastric acidity--a two-centre open randomised cross-over placebo-controlled trial

BACKGROUND

Rennie and Riopan Gel are 2 of the most well-known and popular over-the-counter antacids; for heartburn symptoms, pain relief is fast with both preparations. A direct comparison with respect to intragastric acidity has not been done yet. The aim of our study was therefore to compare the effects of both preparations on intragastric acidity of fasting volunteers.

METHODS

The study was conducted as an open, randomised, placebo-controlled, 2-centre cross-over study. On different days, 24 healthy adult volunteers (11 males and 13 females) received equimolar acid-neutralising amounts of either Riopan Gel (800 mg magaldrate) or 2 tablets of Rennie (680 mg calcium carbonate and 80 mg magnesium carbonate) or no drug (control) with a wash-out period of at least 4 days between applications. The intragastric pH was measured for 3 h by intragastric pH-metry. The primary endpoint was the median time lag before intragastric pH >3.0 was reached for 10 consecutive min after drug administration.

RESULTS

For both antacids, the median pH during the first 30 min after drug administration was statistically significantly different from placebo (p < 0.05), but there was a statistically significant increase in pH during the first 5 min for Riopan Gel only.

CONCLUSION

Compared to placebo, both antacids (Rennie and Riopan Gel) have short-lasting effects on intragastric acidity. There is no statistically significant difference between the 2 preparations, except in the first 5 min, indicating a faster onset of action for Riopan Gel. We conclude that the antacid formulation (tablet or liquid) has little influence on intragastric acidity.

Effect of an Aluminum- and Magnesium-Containing Antacid on the Bioavailability of Garenoxacin in Healthy Volunteers

STUDY OBJECTIVE

To evaluate the effect of an aluminum- and magnesium-containing antacid (Al-Mg antacid), which contains a high concentration of cations, on the pharmacokinetics of garenoxacin.

DESIGN

Prospective, randomized, open-label, control-balanced, residual-effects-design study.

SETTING

Pharmaceutical company-affiliated study clinic.

SUBJECTS

Twenty healthy volunteers who were garenoxacin naïve.

INTERVENTION

Subjects were randomly assigned to receive three of six oral treatments, each separated by a 7-day washout period: garenoxacin 600 mg administered alone, with concomitant Al-Mg antacid, 2 or 4 hours before Al-Mg antacid, or 2 or 4 hours after Al-Mg antacid. The Al-Mg antacid dose was 20 ml, which contained aluminum hydroxide 900 mg and magnesium hydroxide 800 mg.

MEASUREMENTS AND MAIN RESULTS

The pharmacokinetics and safety of garenoxacin were assessed. For each treatment, serial blood samples for pharmacokinetic analysis of garenoxacin were collected before and up to 72 hours after garenoxacin dosing. Absence of effect of Al-Mg antacid on garenoxacin area under the concentration-time curve from time zero extrapolated to infinity (AUC(0-infinity)) and maximum observed plasma concentration (C(max)) were concluded if the 90% confidence interval of the adjusted geometric mean ratios with and without the antacid were contained within 0.80-1.25 and 0.70-1.43, respectively. Exposure to garenoxacin measured by AUC(0-infinity), a parameter well correlated with efficacy, was reduced by 58% when coadministered with Al-Mg antacid and reduced by 22% and 16% when administered 2 and 4 hours after the antacid, respectively. Administration of garenoxacin 4 hours before Al-Mg antacid had no effect on AUC(0-infinity) or C(max) of garenoxacin, whereas administration 2 hours before the antacid resulted in a nonclinically relevant (12%) reduction in AUC(0-infinity) of garenoxacin.

CONCLUSION

Exposure to garenoxacin was significantly decreased when garenoxacin was coadministered with Al-Mg antacid or within 2 hours after the antacid. The magnitude of the changes in garenoxacin exposure suggests that garenoxacin should be administered at least 2 hours before or 4 hours after administration of Al-Mg antacid or other cation-containing products.

The Clinical Noncompliance of Oral Sotalol/Magnesium for Prophylactic Treatment of Atrial Fibrillation After Coronary Artery Bypass Grafting

BACKGROUND

Postoperative atrial fibrillation has been refractory to many attempted pharmacologic prevention methods and, when effective, side effects have been described. The present aim was to study the clinical compliance of a suggested prophylactic treatment, oral sotalol, and magnesium.

METHODS

Coronary-bypass patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium supplementation were enrolled (n = 49) with an intention-to-treat strategy and being compared with a matched control group (n = 844). A protocol listed exclusion criteria of clinical compliance that was postoperatively evaluated prior to and during treatment.

RESULTS

Twenty-seven of the 49 enrolled patients (55%) were compliant to sustain the treatment according to the protocol. The remaining patients were postoperatively excluded, mainly because of hemodynamic reasons, of whom 14 were noncompliant to initiate any treatment. The AF occurrence in the compliant group was 7% versus 36% in noncompliant patients (p = 0.035), and 24% in the control group (p = 0.076). However, with an intention-to-treat policy the overall AF incidence became 18%. The subgroups of enrolled patients demonstrated skewing phenomena. The noncompliant group had higher requirement for inotropic support (p = 0.029) and longer aortic cross-clamp time (p = 0.048) compared to compliant patients. Further, the body weight of noncompliant patients was markedly lower than in the compliant counterpart (p = 0.015).

CONCLUSIONS

The tested treatment protocol showed limited compliance among routine cardiac-surgery patients, and further, introduced a biased selection of patients that skewed the results and may have partly explained the treatment effect.

Antacid interaction with new quinolones: dose regimen recommendations based on pharmacokinetic modeling of clinical data for ciprofloxacin, gatifloxacin and norfloxacin and metal cations

OBJECTIVE

New quinolones (NQs) are widely used to treat various infections. However, concomitant oral administration of metal cations may decrease absorption of NQs and consequently decrease their blood concentration and pharmacological effect. A convenient approach to avoid this interaction is to separate the dosages by a certain interval. In this study, we aimed to develop a novel pharmacokinetic model to describe NQs-metal cation interactions in order to estimate the optimal dosing interval.

METHODS

Plasma concentration-time profiles of NQs after administration without or with metal cations at various dosing intervals were collected from the literature and analyzed with a pharmacokinetic model incorporating the formation ofNQs-metal cations complex. The model was fitted to the reported time profiles ofciprofloxacin (CPFX) plasma concentration after concomitant administration with aluminum hydroxide/magnesium hydroxide antacid (Al/Mg antacid; Maalox, Maalox70) at various dosing intervals to obtain the pharmacokinetic parameters of CPFX. Model analysis was also carried out for gatifloxacin (GFLX) and norfloxacin (NFLX).

RESULTS

The developed model could adequately explain the interactions in all the combinations investigated. The model predicted, in the cases of usual doses of CPFX with Maalox, GFLX with Maalox70 and NFLX with sucralfate, that the NQ should be administered 4.5, 4.5 and 3.5 hours after, or 1, 1 and 0.5 hours before the administration of metal cations, respectively, to ensure 90% of control absorption.

CONCLUSIONS

The developed model can adequately describe the extent of interaction between NQs and metal cations, and should be clinically useful to design dosage regimens to circumvent the interaction.

Osteomalacia from Mg-containing antacid: a case report of bilateral hip fracture

Non-prescribed antacid drugs that contain magnesium and aluminum are widely used in the treatment of gastritis and peptic ulcer. One of the side effects of these antacid drugs is that they bind phosphate in the gut and result in its malabsorption. In this paper, a 42-year-old female patient who used magnesium hydroxide (Magnesie calcinee powder 100 g) to benefit from its laxative feature, and developed osteomalacia after losing 90 kg in 2 years will be presented by going through the related literature. She had widespread joint pain and could hardly walk without the help. Ca, P and vitamin D were at lower limit of normal, ALP, Mg and PTH were increased in her laboratory tests. There were stress fractures at the femur neck and at the upper part of the tibia in plane radiographies. The patient was hospitalized with the diagnosis of osteomalacia and she was treated successfully.

Bioassay by intratracheal instillation for detection of lung toxicity due to fine particles in F344 male rats

We have established and documented an in vivo bioassay for detection of hazards with intratracheally instilled fine particles, which can be used for risk assessment of toxicity of materials inhaled into deep lung tissue of humans (Yokohira et al. Establishment of a bioassay system for detection of lung toxicity due to fine particle instillation: sequential histopathological changes with acute and subacute lung damage due to intratracheal instillation of quartz in F344 male rats. J Toxicol Pathol 2005;18:13-8). For validation we here examined toxicity of fine particles from quartz, hydrotalcite, potassium octatitanate, palladium oxide and carbon black with this bioassay. A total of 108, 10-week-old F344/DuCrj male rats were randomly divided into 8 groups. Groups 1 to 5 underwent intratracheal instillation of the 5 test particles (4 mg/rat) suspended in 0.2 ml vehicle (saline or 10% propylene glycol and 1% sodium carboxymethyl cellulose in saline: PG-CMC) with a specially designed aerolizer, and subgroups of 7 rats were killed on Days 1 and 28 thereafter. Groups 6 and 7 similarly were exposed to saline and PG-CMC, respectively, as vehicle controls, while group 8 was maintained untreated. Using histopathological changes and immunohistochemically assessed bromodeoxyuridine (BrdU) labeling indices, inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-3 (MMP-3) levels as end points, the quartz treated group exhibited high toxicity, while the values for the other particle-treated groups pointed to only slight effects. Although additional efforts are needed to establish advantages and disadvantages with our bioassay, models featuring intratracheal instillation clearly can be useful for detection of acute or subacute lung toxicity due to inhaled fine particles by using histopathological scoring and markers like BrdU and iNOS for screening purposes in short-term studies.

A comparison between sodium alginate and magaldrate anhydrous in the treatment of patients with gastroesophageal reflux symptoms

The aims of the present study were to compare effects of sodium alginate and the antacid magaldrate anhydrous in adults with gastroesophageal reflux (GOR) symptoms. Patients with heartburn and/or acid regurgitation for at least 3 days in the week before the study started (n=203) were randomized to receive a single dose of sodium alginate or magaldrate anhydrous at the onset of symptoms during a 3-day run-in period. Patients with symptoms during the run-in (n=191) were rerandomized to receive a 14-day treatment with either drug given as four daily doses. A speed of action < or =30 min was significantly more frequent among patients in the alginate group (49.4% vs. 40.4%; P=0.0074). A trend toward a more prolonged duration of action (median: 16.5 vs. 12.7 hr) and a greater sum of the symptom intensity difference (median: 40.0 vs. 31.0) was observed in the sodium alginate group. Total disappearance of symptoms was reported in 81.6% and 73.9% of patients in the sodium alginate group and magaldrate group, respectively. We conclude that sodium alginate was faster than magaldrate in relieving GRO symptoms and showed a tendency toward a more prolonged duration of action and a higher level of efficacy.

Intercalation of the radical scavenger ferulic acid in hydrotalcite-like anionic clays

Hydrotalcite is a biocompatible lamellar anionic clay formed by double hydroxide layers with a metal cation coordinating four OH groups. The different layers are held together by anionic hosts that can be replaced by a simple ion-exchange process. The synthetic Mg-Al-hydrotalcite was used to intercalate ferulic acid, a compound that shows antioxidant properties due to its free radical scavenger capacity. Analysis of the intercalated compound showed a good intercalation percentage (35.53%) accompanied by an increase of the interlayer space from 7.8A (chloride form) to 17.1A due to the presence of the ferulate. The intercalation product was stable in water, did not show any significant degradation after UV-irradiation, had a higher capacity of UV absorption in comparison to both the pure ferulic acid and ferulic acid-hydrotalcite chloride physical mixture. The intercalated compound was formulated in a siliconic cream and the ferulate in vitro release profiles determined.

Effect of antacids and ranitidine on the single-dose pharmacokinetics of fosamprenavir

Single doses of MAALOX TC and ranitidine were administered separately with 1,400 mg of fosamprenavir (FPV). MAALOX TC decreased the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) for plasma amprenavir (APV) by 18% and the maximum concentration of drug in serum (C(max)) by 35%; the plasma APV concentration at 12 h (C(12)) increased by 14%. Ranitidine at 300 mg decreased the AUC(0-24) for plasma APV by 30% and C(max) by 51%; C(12) was unchanged. FPV may be coadministered with antacids without concern and without separation in dosing; however, caution is recommended when FPV is coadministered with histamine(2)- receptor antagonists or proton pump inhibitors.

Prospective randomized study of viscous Lidocaine versus Benzocaine in a GI cocktail for dyspepsia

We hypothesized that Benzocaine (Hurricaine) would work as quickly and effectively as viscous Lidocaine in this preparation. This was a prospective randomized, single-blinded comparison between Benzocaine and Lidocaine as the topical anesthetic in a gastrointestinal (GI) cocktail. Patients 18 years or older were approached for participation when a GI cocktail was ordered by the Emergency Physician. Patients were randomized to equivalent doses of either Benzocaine or viscous Lidocaine in addition to 30 cc of Maalox and 10 cc of Donnatal. Assessment using a visual analog pain scale occurred at time intervals of 0, 5, 15, and 30 min. Eighty-two patients were enrolled (44 to Benzocaine, 38 to viscous Lidocaine), with each group having a statistically significant improvement in pain (p < 0.001). There were no statistical differences between the Benzocaine and viscous Lidocaine groups in terms of the relief of symptoms at each of the assessment times. There were no adverse outcomes in either group.

The effects of oral magnesium hydroxide administration on rumen fluid in cattle

This study was conducted to determine the effects of oral magnesium hydroxide administration on rumen fluid in cattle. Six lactating Holstein cows (4-7 years of age) with rumen fistulas were studied. Cattle were randomly assigned to receive boluses of magnesium hydroxide (162 g) or a powdered form (450 g dissolved in 3.5 L of water) PO daily for 3 days. Analysis of rumen fluid, blood gas tensions, and pH and measurement of serum magnesium concentrations were conducted daily. The study was discontinued after 72 hours, or sooner if rumen pH exceeded 8.0. After at least 3 weeks, the study was repeated with each cow receiving the other form of magnesium hydroxide (powder or bolus). Compared with baseline rumen pH (mean +/- SD: 6.22 +/- 0.28), magnesium hydroxide boluses caused a significant increase (P < .05) in rumen pH after 48 (7.27 +/- 0.11) and 72 (8.01 +/- 0.16) hours of administration, whereas the powdered form caused a significant increase (P < .05) in rumen pH after 24 (7.54 +/- 0.19) and 48 (8.43 +/- 0.22) hours of administration. Both the powdered and bolus forms of magnesium hydroxide decreased rumen protozoal numbers and increased methylene blue reduction times compared with baseline values. There was no change in blood pH, bicarbonate, or base excess values. Serum magnesium concentrations were significantly increased (P < .05) in cows that received the magnesium hydroxide powder. The results of this study indicate that magnesium hydroxide has a potent alkalinizing effect on rumen pH and significantly decreases rumen microbial activity.

Pantoprazole maintenance therapy prevents relapse of erosive oesophagitis

OBJECTIVES

To compare the safety and efficacy of pantoprazole with ranitidine for the maintenance of endoscopically documented healed (grade 0 or 1) erosive oesophagitis.

METHODS

Patients (371) were randomly assigned to receive pantoprazole 10, 20 or 40 mg or ranitidine 150 mg. Endoscopies were performed after 1, 3, 6 and 12 months or when symptoms suggesting relapse (grade = 2) developed. Gastric biopsies were obtained at baseline and on at least one postbaseline visit. Symptom-free days and Gelusil use were assessed.

RESULTS

Pantoprazole was significantly (P < 0.001) more effective in maintaining erosive oesophagitis healing. After 12 months, 33%, 40%, 68% and 82% of patients remained healed for the ranitidine and pantoprazole 10, 20 and 40 mg groups, respectively. Daytime and night-time heartburn were eliminated in > 90% of days for the pantoprazole 40 mg group. Gelusil use was significantly lower with pantoprazole 20 and 40 mg than with ranitidine (P < 0.02) during the first 9 months.

CONCLUSIONS

Twelve months of maintenance therapy with pantoprazole (10-40 mg once daily) was superior to ranitidine (150 mg twice daily) in maintaining erosive oesophagitis healing. Pantoprazole 40 mg provided the most consistent efficacy and was well tolerated.

Lack of pharmacokinetic interaction between the oral anti-influenza neuraminidase inhibitor prodrug oseltamivir and antacids

AIMS

Oseltamivir is an oral ester prodrug of its active metabolite Ro 64-0802, a potent and selective neuraminidase inhibitor of the influenza virus. The object of this study was to evaluate whether the oral absorption of oseltamivir was reduced in the presence of two main classes of antacid, Maalox(R) suspension (containing magnesium hydroxide and aluminium hydroxide) and Titralac(R) tablets (containing calcium carbonate).

METHODS

Twelve healthy volunteers completed a randomized, single dose, three-period crossover study. Each volunteer received in a fasted state, 150 mg oseltamivir alone (Treatment A), 150 mg oseltamivir with a 20 ml Maalox suspension (Treatment B), and 150 mg oseltamivir with four Titralac tablets (Treatment C), with 7-10 days washout in between treatments. Plasma and urine concentrations of oseltamivir and Ro 64-0802 were measured using a validated h.p.l.c./MS/MS assay. Pharmacokinetic parameters were calculated for oseltamivir and Ro 64-0802. Since antacids are locally acting drugs and generally not expected to be absorbed substantially into the systemic system, no plasma or urine concentrations of antacids were measured.

RESULTS

Bioequivalence was achieved for the primary pharmacokinetic parameters Cmax and AUC(0, infinity ) of Ro 64-0802 following administration of oseltamivir with either Maalox suspension or Titralac(R) tablets vs administration of oseltamivir alone. The bioavailability (90% confidence intervals) of Ro 64-0802 following administration of oseltamivir together with Maalox suspension vs administration of oseltamivir alone, was 90% (83.6, 96.9%) for C(max) and 94.1% (91.4, 96.9%) for AUC(0, infinity); similarly, for Titralac tablets, the equivalent values were 95.1% (88.3, 102%) for C(max) and 94.7% (91.9, 97.5%) for AUC(0, infinity).

CONCLUSIONS

The coadministration of either Maalox suspension or Titralac tablets with oseltamivir has no effect on the pharmacokinetics of either oseltamivir or Ro 64-0802, and conversely, there is no evidence that coadministration with oseltamivir has an effect on the safety and tolerability of either Maalox suspension or Titralac tablets. There was no pharmacokinetic interaction between oseltamivir with either antacid, demonstrating that the oral absorption of oseltamivir was not impaired in the presence of antacids containing magnesium, aluminium or calcium.

The effects of cimetidine and antacid on the pharmacokinetic profile of sildenafil citrate in healthy male volunteers

AIMS

To examine the effect of concomitant cimetidine or antacid administration on the pharmacokinetic profile of sildenafil citrate in healthy male volunteers in two open-label, randomized studies.

METHODS

The first study was a parallel-group design in which 22 healthy male volunteers received sildenafil (50 mg) on days 1 and 5 and cimetidine (800 mg) or placebo on days 3, 4, 5, and 6. Blood samples were collected predose and at specified times up to 48 h postdose on days 1 and 5 to determine plasma levels of sildenafil and its metabolite, UK-103,320. The second study was a two-way crossover design in which 12 volunteers received sildenafil with or without a 30-ml dose of a magnesium hydroxide/aluminium hydroxide antacid. Blood samples were collected and analysed as in the first study. The two study periods were separated by at least 14 days.

RESULTS

Coadministration of cimetidine had no statistically significant effect on the tmax or kel of sildenafil but caused a statistically significant increase in sildenafil AUCt and Cmax of 56% and 54%, respectively (P<0.01). Differences between the two treatment groups were smaller for the metabolite than for sildenafil, although cimetidine treatment did significantly (P<0.05) increase the AUCt for UK-103,320 by 30%. Antacid coadministration had no statistically significant effect on any pharmacokinetic parameter of sildenafil or UK-103,320. Whether taken alone, with cimetidine, or with an antacid, sildenafil was well tolerated. Most adverse events were mild in nature, and no subject withdrew from either study for any reason related to the drug.

CONCLUSIONS

Cimetidine co-administration produced an increase in sildenafil plasma levels; however, this increase is not sufficient to warrant dosage adjustment of either drug. Antacid coadministration had no effect on the pharmacokinetic profile of sildenafil.

Effect of an orally administered antacid agent containing aluminum hydroxide and magnesium hydroxide on abomasal luminal pH in clinically normal milk-fed calves

OBJECTIVE

To determine the effects of a commercially available orally administered antacid agent containing aluminum hydroxide and magnesium hydroxide on abomasal luminal pH in clinically normal milk-fed calves.

DESIGN

Randomized trial.

ANIMALS

5 male dairy calves.

PROCEDURE

Throughout the study, calves were fed milk replacer at 7:30 AM and 7:30 PM. Cannulae for pH electrodes were placed in the abomasal body and pyloric antrum. Treatments consisted of oral administration of a high (50 ml) or low (25 ml) dose of the antacid agent and oral administration of milk replacer alone (control). Antacid was given at 7:30 AM, 3:30 PM, and 11:30 PM, and luminal pH was monitored continuously for 24 hours, beginning 15 minutes before administration of the first dose of antacid.

RESULTS

Administration of the first dose of antacid at the time of the morning feeding resulted in an increase in mean abomasal body luminal pH of < 1 pH unit, whereas administration of the second and third doses of the antacid caused transient (< 3 hours) increases in mean luminal pH of approximately 1.5 (low dose) and 2.5 (high dose) pH units.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that clinically normal milk-fed calves given a commercially available antacid agent, PO, will have a transient increase in abomasal luminal pH. Such agents may, therefore, have a role in the treatment of abomasal ulceration in calves; however, the long-term effects of orally administered antacid agents in milk-fed calves and the clinical efficacy of such agents in treating abomasal ulceration remain to be determined.

Hydrotalcid Multicenter Clinical Cooperative Group. [Hydrotalcite in the treatment of reflux esophagitis: a multicenter clinical study]

OBJECTIVE

To investigate the effect of hydrotalcite on reflux esophagitis.

METHODS

45 patients with endoscopically proven reflux esophagitis were enrolled in 6 Chinese hospitals. All the patients were randomly divided into two groups. 25 patients were allocated to a study group; hydrotalcite was given 1.0 g four times daily for 6 weeks. The remaining 20 patients were allocated to a control group; omeprazole was given 20 mg twice daily in the first 2 weeks and 20 mg once daily in the following 4 weeks. Reflux symptoms including heartburn, regurgitation and chest pain were evaluated during visits after 1, 2, 4 and 6 weeks. At the end of 6 weeks, endoscopy was performed to study the healing rate. Monitoring of esophageal 24-hour pH and bilirubin was performed in 17 patients of the study group and 13 patients of the control group respectively.

RESULTS

Both hydrotalcite and omeprazole could improve the reflux symptoms. One week after treatment the symptom scores of heartburn, regurgitation and chest pain were significantly decreased in both groups (P < 0.01) and symptom scores were decreased even more after 6 weeks. There was no significant difference between the two groups (P > 0.05). At the end of the treatment, endoscopic healing rate and effective rate was 64.28% and 78.57% respectively in the study group, being similar to that of 66.67% and 93.33% in the control group. Combined monitoring of 24-hour esophageal pH and bilirubin showed that both hydrotalcite and omeprazole could greatly decrease the total time of pH < 4, total time percentage of pH < 4, total time of bilirubin absorption > or = 0.14 and total time percentage of bilirubin absorption > or = 0.14. After treatment, the results of 24-hour esophageal pH and bilirubin combined monitoring became normal in 5 patients (29.41%) of the study group, while the results became normal in 10 patients (76.92%) of the control group (P < 0.05).

CONCLUSION

Hydrotalcite is an effective medication for the treatment of reflux esophagitis.

The role of mechanical bowel preparation for colonic resection and anastomosis: an experimental study

BACKGROUND AND AIMS

To evaluate the effect of mechanical bowel preparation (MBP) on colonic resection and anastomosis.

PATIENTS AND METHODS

Mongrel dogs were divided into two groups of 20 animals each. During the preoperative period (24 h) group A was not subjected to MBP, and group B was fasted and ingested 20 ml magnesium hydroxide plus 15 ml/kg 10% mannitol orally. All animals underwent segmental colectomy followed by end-to-end anastomosis. The survivors of both groups were reoperated upon on the 7th postoperative day.

RESULTS

Mortality before reoperation was significantly higher in group A (45%) than in group B (10%; P<0.05). Upon reoperation on surviving animals the incidence of localized anastomotic leakage, leakage with peritonitis, and healed anastomoses was 72.72%, 9.09%, and 18.8% in group A, and 66.66%, 22.22%, and 11.11% in group B, respectively (P>0.05). Aerobic and anaerobic bacterial cultures showed similar growth in the two groups.

CONCLUSION

We conclude that the omission of MBP increased the mortality due to early anastomotic leakage with peritonitis; MBP did not change the rate of localized anastomotic leakage, leakage with peritonitis, or intact anastomoses on the 7th day; no quantitative or qualitative differences were observed in the bacteria isolated from the two groups.

[Inhibition of HCFU absorption after resection for gastric cancer--application of hydroxyaluminium gel]

HCFU (carmofur; Mifurol) is an 5-FU analog. The maximum blood concentration of HCFU in HCFU fraction (Cmax) after gastric resection was higher than before resection. Hot sensation and pollakiuria, characteristic side effects of HCFU, are dependent on concentration of HCFU fraction in blood. Therefore, it is considered that the frequency of occurrence of side effects after gastric resection is high. For that reason, we thought that if absorption of HCFU could be reduced, fewer side effects would result. We focused on the fact that drugs which include aluminium gel may decrease absorption in combined drugs, and thought it would be possible to delay absorption in HCFU by using them. We studied the HCFU concentration in the HCFU fraction and 5-FU concentration in blood, respectively, in two cases: 1) single oral administration of HCFU 100 mg and 2) coadministration with hydroxyaluminium gel (ALG) 10 ml in the whole or partial resection of gastric cancers for 8 patients. We found that the concentration of HCFU in the HCFU fraction 2 hours after its administration decreased significantly: 3.24 +/- 1.78 (single administration), 1.37 +/- 0.91 (coadministration with ALG) (p = 0.023). HCFU concentration in the HCFU fraction seemed to decrease for coadministration with ALG in the area under the time-blood concentration curve (AUG) (p = 0.071). The 5-FU concentration did not seem to decrease in either case. From these results, the coadministration of HCFU with ALG seems to be effective for the inhibition of adverse drug reaction after the resection of gastric cancers.

[Treatment of erosive gastropathy caused by nonsteroidal anti-inflammatory agents using low doses of antacids]

In an open clinical, endoscopy controlled study involving 31 patients with erosive NSAIDs-induced gastropathy without Helicobacter pylori infection, the effect of low dose of antacids (120 mmol/l) with aluminium oxide and magnesium oxide (Maalox) administered for 4 weeks was followed. The administration of NSAIDs was not interrupted during the time of treatment. Healing rate of the gastric erosions after four weeks reached 65% (20/31) and endoscopic score in the gastric mucosa proved significant improvement (0.97 +/- 0.49 compared to 0.07 +/- 0.25, p < 0.01). Our results suggest efficacy of low dose antacids containing aluminium in the treatment of NSAIDs-induced gastric erosions.

[Kinetics of aluminum absorption and serum concentration in chronic renal insufficiency]

After administration of a single dose of an aluminium containing antacid (Tisacid) to eight non dialysis patients in various stages of chronic renal insufficiency, the kinetics of serum aluminium absorption was studied. Serum aluminium peaked at two points of time, aluminium absorption being biphasic in renal patients comparing with monophasic kinetic in controls. At the same time, already at 24 hrs after Tisacid ingestion, the aluminium concentration was almost twice as high as initially even in mild renal insufficiency. These results are at variance with the rapidly reversible, monophasic aluminium absorption observed earlier in healthy subjects and in non-renal patients with duodenal ulcer. To ward off complications, a strong warning is given against administration of any aluminium-containing medicament or food to subjects with reduced renal function.

The effect of oral magnesium, alone or as an adjuvant to sotalol, after cardioversion in patients with persistent atrial fibrillation

AIMS

To determine whether magnesium given orally decreases the recurrence rate of atrial fibrillation after elective direct current cardioversion of persistent atrial fibrillation.

METHODS AND RESULTS

Consecutive outpatients were randomized to treatment with oral magnesium (10.3 mmol) or placebo twice daily in a double-blind fashion. Two groups were studied; magnesium study: 170 patients with atrial fibrillation persistent for >1 month, scheduled for their first direct current cardioversion. No concomitant antiarrhythmic drugs of class I or III were allowed. Sotalol and magnesium study: 131 patients with recurrence of persistent atrial fibrillation after previous direct current cardioversion, or a history of paroxysmal atrial fibrillation, treated with sotalol. Patients were followed until recurrence of atrial fibrillation or for at least 6 months. Magnesium study: at cardioversion 67 of 85 (79%) in the placebo group and 64 of 85 (75%) in the magnesium group had converted to sinus rhythm. At the end of the study, with a follow-up of 6 to 42 months, 15% of patients in the placebo group and 19% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.37). Sotalol and magnesium study: pharmacological conversion to sinus rhythm, after oral treatment, was achieved in 34 of 131 (26%) patients. Sinus rhythm, with or without cardioversion, was restored in 89% and 85% of the patients in the placebo and magnesium groups, respectively. At the end of the study, with a follow-up of 6 to 42 months, 37% of patients in the placebo group and 30% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.64).

CONCLUSION

In patients with persistent atrial fibrillation, oral treatment with magnesium alone or as an adjuvant to sotalol, does not influence the recurrence rate of atrial fibrillation after elective cardioversion.

Protection by acidified Maalox against indomethacin-induced gastric antral ulceration in hamsters

The protective capability of Maalox against indomethacin-induced gastric damage was evaluated in hamsters. The effect of acidification on the gastroprotection provided by Maalox against such damage was also determined. Maalox was ineffective against indomethacin-induced gastric antral ulceration in hamsters. Acidification of this antacid to pHs of 1.5-3.5 resulted in significant (80-90%) gastroprotection against indomethacin. Macroscopic and histologic evidence of binding by acidified Maalox to the hamster antral mucosa was clearly evident. In summary, no correlation exists between acid neutralization and the gastroprotective capability of Maalox against indomethacin in hamsters. The gastroprotection by acidified Maalox against antral ulceration in this species corresponds well with the reported presence of its hexaaquoaluminum cation moiety at a pH below 4. Such gastroprotection may involve binding of this cation to the hamster pyloric antrum thereby protecting the antral mucosa against indomethacin-induced ulceration.

Antacid/anticholinergic, cimetidine, and placebo in treatment of active peptic ulcers

Seventy-two patients with duodenal (54) or prepyloric (18) ulcers have taken part in a 12-week double-blind trial. Twenty-four patients received cimetidine, 1 g/day; 24 patients received 10 ml of an antacid suspension (buffering 85 mmol acid) 1 and 3 h after every meal and at bedtime and 0.6 mg L-hyoscyamine in sustained-release tablets twice a day; and 24 patients received placebo. The healing rate after 3 weeks' treatment was 67% (p less than 0.005 compared with placebo) with cimetidine, 50% (p less than 0.01) with antacid/anticholinergic, and 13% with placebo. After 6 weeks' treatment 83% were healed with cimetidine (p less than 0.005 compared with placebo), 96% with antacid/anticholinergic (p less than 0.005), and 33% with placebo. A further 6 weeks' treatment gave healing rates of 96% for cimetidine, of 100% for antacid/anticholinergic, and of 50% for placebo. Compared with placebo, cimetidine but not antacid/anticholinergic caused a faster relief of night-time ulcer pain (p less than 0.05). There was a significant correlation between healed ulcers and complete relief of ulcer symptoms (p less than 0.05). In the placebo group the ulcers of nonsmokers healed to a higher extent than those of smokers (p less than 0.05). During 1 year of follow-up there was no difference between the two actively treated groups in number or severity of symptomatic relapses. Time to relapse was, however, significantly shorter after treatment with cimetidine than after antacid/anticholinergic (p less than 0.05). Recurrences occurred more often (p less than 0.05) after slow healing (6-12 weeks) than after fast healing (3 weeks).

Comparison of 200 mg cimetidine with multiple doses of antacid on extent and duration of rise in gastric pH in volunteers

The effects on gastric pH of a single administration of 200 mg cimetidine (Tagamet HB) were compared to multiple doses of a liquid antacid (Mylanta) using a pH microelectrode. Gastric pH was monitored for 8 hr in 20 normal fasting volunteers in a crossover design to compare Tagamet HB (two 100-mg tablets administered as a single dose) with Mylanta Suspension, an initial 17.5-ml dose of antacid with additional doses given when gastric pH fell below 3.5. Both treatments increased the pH above 3.5 during the first hour following treatment, with Mylanta being more effective than Tagamet HB. Interestingly, to sustain the reduction in acidity during this 1-hr interval, a mean of 2.45 doses of antacid were administered. Although multiple doses of Mylanta kept the pH above 3.5 (for at least 25% of the time) for the first 4 hr, the single administration of 200 mg of Tagamet HB maintained gastric pH above 3.5 (greater than 25% of time) for the full 8 hr of the study. Compared to Mylanta, the percent of time gastric pH was >3.5 was significantly higher with Tagamet HB during the 3rd to 8th hour after dosing. This study demonstrates that 200 mg of cimetidine administered as Tagamet HB is significantly more effective and has a much longer duration of action in raising gastric pH >3.5 than six doses of Mylanta.

Pharmacokinetics of gatifloxacin and interaction with an antacid containing aluminum and magnesium

The pharmacokinetics of gatifloxacin (400 mg orally) and the influence of the antacid aluminum magnesium hydroxide (20 ml of Maalox 70) on the bioavailability of gatifloxacin in 24 healthy volunteers were assessed. In an open, randomized, six-period crossover study, the volunteers received either gatifloxacin alone (treatments A and D); aluminum magnesium hydroxide concomitant with gatifloxacin (treatment C); or aluminum magnesium hydroxide 2 h before (treatment B), 2 h after (treatment E), or 4 h after gatifloxacin administration (treatment F). Gatifloxacin concentrations were measured by a validated bioassay and high-performance liquid chromatography. Pharmacokinetics of a single 400-mg dose of gatifloxacin alone were characterized as follows (mean +/- standard deviation): peak concentration (Cmax), 3.8 +/- 0. 5 (treatment A) and 3.4 +/- 0.9 (treatment D) microgram/ml; time to Cmax, 1.4 +/- 0.8 (treatment A) and 1.7 +/- 0.7 (treatment D) h; area under the curve from time zero to infinity (AUC0-infinity), 33. 5 +/- 5.9 (treatment A) and 31.4 +/- 3.4 (treatment D) microgram. h/ml; urine recovery, (83 +/- 6)% (treatment A) and (84 +/- 8)% (treatment D). Comparison of the results obtained by bioassay showed a good correlation. Aluminum magnesium hydroxide administration 2 h before (treatment B) or concomitant with (treatment C) gatifloxacin decreased the Cmax by 45% (2.1 +/- 1.2 microgram/ml) or even 68% (1.2 +/- 0.4 microgram/ml) highly significantly (P < 0.01). AUC0-infinity was significantly reduced from 33.5 +/- 5.9 to 19.4 +/- 6.9 microgram. h/ml (by 42%) or even to 11.9 +/- 3.3 microgram. h/ml (by 64%) (P < 0. 01). If aluminum magnesium hydroxide was given 2 h after gatifloxacin (treatment E), there was no significant reduction of concentration in serum but AUC0-infinity was significantly reduced from 31.4 +/- 3.4 to 25.9 +/- 5.3 microgram. h/ml (18%) (P < 0.01). Aluminum magnesium hydroxide given 4 h after gatifloxacin (treatment F) showed no influence on the gatifloxacin pharmacokinetics. Therefore, the optimal time between gatifloxacin application and the intake of an aluminum-containing antacid should be 4 h.

[Intravesical instillation of Maalox for the treatment of bladder hemorrhage due to prostate cancer invasion: report of two cases]

Two cases treated by intravesical instillation of Maalox for bladder hemorrhage are reported. A 79-year-old man and an 81-year-old man were admitted because of macroscopic hematuria and bladder tamponade. In both cases, bladder hemorrhage caused by bladder invasion of prostate cancer had not improved after bladder lavage, intravenous drip infusion and medication of hemostatics. In the first case, bladder hemorrhage had decreased 4 days after the intravesical instillation of 50-100 ml Maalox for an hour per day. In the second case, irrigation of Maalox was performed because of the difficulty of intravesical instillation of Maalox due to irritable bladder. The bladder hemorrhage had not completely disappeared but improved 5 days after the bladder irrigation of 100 ml of Maalox with 100 ml of 0.9% NaCl for an hour per day. This method is easy and can be performed without complications. This method might be useful as first-line therapy in the case of severe bladder hemorrhage.

Influence of the antacid Maalox on the pharmacokinetics of capecitabine in cancer patients

PURPOSE

In the present study the possible influence of the antacid Maalox on the pharmacokinetics of capecitabine (Xeloda) and its metabolites was investigated in cancer patients.

METHODS

A total of 12 patients with solid, predominantly metastatic tumors of various origin received a single oral dose of 1250 mg/m2 of capecitabine (treatment A), a single oral dose of 1250 mg/m2 of capecitabine followed immediately by 20 ml of Maalox (treatment B), and a single oral dose of 1250 mg/m2 of capecitabine followed 2 h later by 20 ml of Maalox (treatment C) in an open, randomized, three-way cross over fashion. Serial blood and urine samples were collected for up to 24 h after each administration. Unchanged capecitabine and its metabolites were analyzed in plasma using liquid chromatography/mass spectrometry and in urine using nuclear magnetic resonance spectroscopy.

RESULTS

Administration of Maalox either concomitantly with capecitabine or delayed by 2 h did not influence the time to peak plasma concentrations (Cmax) or the elimination half-lives of capecitabine and its metabolites. Unexpectedly, moderate increases in the Cmax and AUC0-infinity values obtained for capecitabine and 5'-deoxy-5-fluorocytidine were observed when Maalox was given together with capecitabine. However, these increases, which ranged between 10% and 31%, were not statistically significant (P > 0.05) and are not of clinical significance. There was no indication of consistent changes in the plasma concentrations of the other metabolites 5'-deoxy-5'-fluorouridine (5'-DFUR), 5-fluorouracil, and alpha-fluoro-beta-alanine. The Cmax and AUC0-infinity values recorded for these three metabolites increased and decreased in a stochastic manner. The magnitude of these changes was low (<13%) and not statistically significant. The primary statistical analysis of the AUC0-infinity obtained for 5'-DFUR provided a P value of 0.4524 and clearly indicated no significant difference between the treatments. The addition of Maalox had no influence on the overall urinary recovery or the proportion of the dose recovered as capecitabine or its metabolites from urine.

CONCLUSION

At the dose used in this study, the effect of concomitantly delivered Maalox on the extent and rate of gastrointestinal absorption of capecitabine is not clinically significant. Therefore, there is no need to adjust the dose or timing of capecitabine administration in patients treated with Maalox.

[Decreased plasma levels of omeprazole after coadministration with magnesium-aluminium hydroxide dry suspension granules]

Plasma levels of omeprazole (OPZ) in Japanese male subjects were compared after a single oral administration of 20 mg of OPZ enteric-coated tablets with and without coadministration of Maalox (MLX suspension) or Maalox dry suspension granules (MLX granules). After coadministration of MLX granules, plasma levels of OPZ markedly decreased, and area under the blood concentration-time curve (AUC) decreased to 26% of that of OPZ alone. In contrast, only a slight decrease in AUC was observed after coadministration of OPZ and MLX suspension. Both MLX suspension and MLX granules exhibited similar degrees of the inhibitory effect on the renal excretion of levofloxacin. It was suggested that a specific and unexpected drug interaction occurred between OPZ enteric-coated tablets and MLX granules via a distinct mechanism from that reported for fluoroquinolones and MLX suspension.

Antacid (A02A) and antiulcer (A02B) drug prescription patterns: predicting factors, dosage and treatment duration

BACKGROUND

A study is made of the pharmaco-epidemiology of antacid (ATC class A02A) and antiulcer (A02B) drug prescriptions during the year 1992.

METHODS

Prescription data were extracted from 1941 case histories of patients over 15 years old from four health care centers in the Valencian Community (Spain). Dosage and treatment duration were evaluated, along with the way in which morbidity, self-evaluated health, the demographic pattern and life-style characteristics influence drug prescription.

RESULTS

The proportion of drug prescriptions increased with age in both sexes (p < 0.01). Drug use depended mainly on chronic diseases. In prescribing antacids, the most influential diagnosis was gastritis (ICD 534, OR: 157), followed by duodenal ulcer (ICD 532, OR: 152) and gastric ulcer (ICD 531, OR: 122), other gastrointestinal disorders (ICD 66, OR: 54) and undefined diagnoses (OR: 15). In the prescription of antiulcer drugs, the most influential diagnoses were gastric and duodenal ulcer (OR: 380 and 342, respectively), and a significant relation was observed with the diagnosis of osteomuscular diseases (OR: 6). Lifestyle and demographic pattern were of marginal importance. The estimated duration of treatment was 85 days. No significant differences were observed in either treatment duration or administered doses of almagate, ranitidine and omeprazole with respect to sex, age or diagnosis.

CONCLUSIONS

Prolonged treatment is common for acid suppression. The widespread use of peptic ulcer drugs is mostly due to excessive prescription for non-ulcer dyspepsia. At the same time, many patients consume these drugs on a long-term basis in the absence of a clear diagnosis. This observation supports the need for appropriate diagnostic and prescription protocols to secure increased economical savings and management results.

Influence of the antacid Maalox and the H2-antagonist cimetidine on the pharmacokinetics of cerivastatin

The possible influence of Maalox 70, an antacid based on magnesium-aluminum hydroxide, and the H2-antagonist cimetidine, both commonly prescribed in hypercholesterolemic patients, on the pharmacokinetics of the new HMG-CoA reductase inhibitor cerivastatin was investigated in 2 separate studies in 8 healthy young male subjects each. Cerivastatin plasma concentration/time profiles were assessed by a specific HPLC assay; in addition, total immunoreactive drug (cerivastatin plus metabolites) was determined by RIA. Single oral doses of 200 micrograms cerivastatin were administered under fasting conditions without or with 10 ml Maalox 70 suspension. The mean AUC and Cmax ratios (combined dosing/monodosing) including 90% confidence intervals were 0.92 (0.73-1.15) and 0.89 (0.72-1.10) for the HPLC data, and 0.99 (0.85-1.14) and 1.03 (0.82-1.30) for the RIA data, respectively. Thus, no interaction of the simultaneous administration of Maalox 70 on the pharmacokinetics of cerivastatin was observed. In a similar controlled, randomized nonblind 2-way crossover design the influence of the H2- antagonist and well-known cytochrome P450 enzyme inhibitor cimetidine was investigated. Eight healthy young male volunteers received single oral doses of 200 micrograms cerivastatin alone or on the fourth day of a 4-day cimetidine 400 mg b.i.d. pretreatment. The mean AUC and Cmax ratios (combined dosing/monodosing) including 90% confidence intervals were 0.98 (0.90-1.08) and 0.91 (0.78-1.07) for the RIA data, and 0.89 (0.82-0.96) and 0.93 (0.80-1.09) for the HPLC data, respectively, clearly indicating that cimetidine and cerivastatin did not interact pharmacokinetically. These results do not only reflect the apparent insensitivity of cerivastatin absorption to possible changes in gastric pH, but demonstrate that the metabolic pathways of cerivastatin, involved in its first-pass metabolism and elimination, are rather insensitive to cytochrome P450 enzyme inhibition induced by cimetidine.

Effect of antacid magaldrate oral suspension on in-vitro and in-vivo availability of indomethacin in dogs

The adsorption of indomethacin onto Riopan and Rioplus (Magaldrate antacid oral suspension U.S.P.) was determined at 37 degrees C in phosphate buffer pH 7.4 and in simulated intestinal fluid U.S.P. pH 7.5. The effect of 20 ml of Riopan, given 1 h after oral administration of Indocid capsules (MSD, 25 mg) to fed dogs, on the bioavailability of indomethacin was also studied. The in-vitro study showed that the logarithm of amount of indomethacin adsorbed was linearly related to the logarithm of free drug concentration in conformity to Freundlich adsorption isotherm. The adsorptive capacities followed the sequence: Riopan (intestinal fluid) = Rioplus (intestinal fluid) > Riopan(phosphate buffer) = Rioplus (phosphate buffer). In all cases the adsorbed drug was eluted almost completely by washing with different volumes of different elution media indicating competitive physical adsorption via weak Van der Waal's attractive forces. The in-vivo study showed that the oral administration of Riopan 1 h after administration of Indocid capsules to fed dogs resulted in a significant (p < 0.05) reduction in plasma concentrations of indomethacin, a non-significant (p > 0.05) change in Cmax, significantly (p < 0.05) shorter Tmax and significantly reduced AUC where it decreased from 15.06 +/- 5.65 to 9.52 +/- 3.69 micrograms h/ml resulted in a relative bioavailability of 63.21% after Riopan administration.

Interaction between sotalol and an antacid preparation

AIMS

The aim of the study was to investigate the pharmacokinetic interaction between sotalol and antacids, and its pharmacodynamic relevance.

METHODS

In a randomized cross-over design with three treatment groups, six healthy volunteers received orally either 160 mg of sotalol alone (phase 1), or 160 mg sotalol plus 20 ml of a suspension of an antacid (MAH; magnesium hydroxide (1200 mg) and aluminium oxide (1800 mg)) (phase 2) or 160 mg sotalol plus the antacid given 2 h after sotalol administration (phase 3). Heart rate and plasma sotalol concentrations were measured before and 1, 2, 3, 4, 6, 8, 12 and 24 h after sotalol administration. Urinary sotalol excretion was measured for 24 h after sotalol application.

RESULTS

Cmax of sotalol decreased from 1.22 +/- 0.22 mgl-1 (phase 1) to 0.89 +/- 0.29 mgl-1 (phase 2) and increased again to 1.27 +/- 0.18 mgl-1 in phase 3. A similar significant change was noted in AUC (15.6 +/- 2.75 mgl-1, 12.3 +/- 3.04 mg h l-1 and 15.0 +/- 2.06 mgl-1) and in the amount of cumulative urinary excretion (79.2 +/- 11.1 mg, 72.1 +/- 11.2 mg and 80.6 +/- 7.9 mg), respectively. tmax and elimination half-life (t1/2,z) of sotalol remained unchanged in the presence of MAH. After combined administration with MAH, the area under the heart rate curve of sotalol was reduced between 0 and 4 h when compared across treatments.

CONCLUSIONS

Combined administration of sotalol and MAH decreased the serum sotalol levels. The interaction can be avoided by a two hour interval between application of these drugs.

Formulation of aspirin-magaldrate double-layer tablets: in vitro evaluation and cytoprotective activity in rats

Double layer 325 mg oral aspirin tablets buffered with magaldrate antacid, 100, 150, 175 and 200 mg (F1, F2, F3 and F4, respectively) were prepared by direct compression. The new formulae were of remarkable hardness and friability. The tablets complied with the requirements of the acid neutralizing capacity, uniformity of dosage units, disintegration and dissolution tests (USP XXIII) for buffered aspirin tablets. The in vitro release pattern of F1 and F1 followed first order kinetics (r = 0.999), while F3 and F4 were released according to a zero order model (r = 0.993). Formulations F2, F3 and F4 as well as the marketed preparations, pure Aspro tablets (Acetylsalicylic acid 320 mg per tablet), or Ascriptin tablets (aspirin 325 mg plus 150 mg Maalox per tablet) were administered to fasted rats by gavage at doses that provided 400 mg aspirin kg-1 and the extent of the induced gastric damage was quantified 6 h later. Ascriptin, F3 and F4 preparations produced significantly less gastric damage (p < 0.05, n = 6) when compared with pure Aspro tablets. There was a clear dose-dependent decrease in the gastric damage following treatment with F2, F3 and F4 preparations, but there was no significant difference between the effects of F3 and F4 which were equipotent with Ascriptin.

Comparison of the effects of ranitidine effervescent tablets and magnesium hydroxide-aluminium oxide on intragastric acidity. A single-centre, randomised, open cross-over study

In previous studies measuring intragastric pH in healthy volunteers it was shown that there was a faster onset of action with ranitidine (CAS 66357-35-5) 300 mg effervescent tablets (Zantac) compared to standard tablets. In a single-centre, randomised, open cross-over study the pH-values obtained over 6 h following the administration of one ranitidine 150 mg effervescent tablet were compared with those after aluminium oxide-magnesium hydroxide (algeldrate, CAS 1330-44-5, Al-Mg-hydroxide) 10 ml and placebo in healthy volunteers. 24 healthy male subjects between 19 and 32 years of age entered the study, 19 subjects were available for all three measurements. After an overnight fast, intragastric pH was monitored for 7 h using a glass electrode and a digital data recorder. The time in % during which the pH was > or = 3.5 and the area under the curve of the obtained pH-curves were compared. There was a highly statistically significant difference between ranitidine effervescent tablets versus Al-Mg-hydroxide and placebo whereas there was no such difference between Al-Mg-hydroxide and placebo. The onset of action of ranitidine effervescent tablets was almost immediate. It is concluded that there was a clear superiority of ranitidine effervescent tablets in healthy volunteers and it is suggested that pH-metry in patients with acidity-related diseases should be investigated for a better understanding of the function of effervescent tablets.

Effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in horses

OBJECTIVE

To assess the effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in clinically normal horses and to develop guidelines on the use of these agents for treatment of peptic ulcer disease in horses.

DESIGN

Prospective, randomized, controlled trial.

ANIMALS

5 clinically normal adult horses with chronically implanted gastric cannulas.

PROCEDURE

Each horse received all 5 treatments (30 g of aluminum hydroxide/15 g of magnesium hydroxide, 12 g of aluminum hydroxide/6 g of magnesium hydroxide, 10.5 g of bismuth subsalicylate, 26.25 g of bismuth subsalicylate, and 5% methylcellulose control) with only 1 experiment performed each day. Gastric pH was measured via a glass electrode inserted through the gastric cannula for 1 hour before treatment and continued for 2 hours after treatment. Food or water was not given to the horses during the experiment. Measurements of gastric pH obtained during posttreatment hours were compared with pretreatment gastric pH values.

RESULTS

Only a dose of 30 g of aluminum hydroxide/ 15 g of magnesium hydroxide resulted in a significant increase in gastric pH over baseline or control values. Mean pH was 5.2 +/- 0.62 and 4.59 +/- 0.48 for posttreatment hours 1 and 2, respectively.

CLINICAL IMPLICATIONS

Oral administration of 30 g of aluminum hydroxide/15 g of magnesium hydroxide to adult horses should result in a mean hourly gastric pH > or = 4.0 for at least 2 hours.

Topical treatments for hydrofluoric acid dermal burns. Further assessment of efficacy using an experimental piq model

Several topical treatments for hydrofluoric acid dermal burns (Zephiran, calcium acetate and magnesium hydroxide antacid soaks, and calcium gluconate gel) were assessed for efficacy in a pig model. Gross appearance and histopathology of treated and untreated burn sites were evaluated. For superficial burns, Zephiran was most effective; calcium acetate, magnesium hydroxide antacid, and calcium gluconate gel were less effective. For deep burns, gross observations showed that calcium acetate and Zephiran were most efficacious, whereas histopathology indicated comparable efficacy of Zephiran, calcium acetate, and calcium gluconate gel for all skin layers. Magnesium hydroxide antacid demonstrated efficacy only for the subdermis. The clinically beneficial effects of both Zephiran and calcium gluconate gel were affirmed. Although results suggest that calcium acetate and magnesium-containing antacids may be beneficial for human hydrofluoric acid dermal burns, these are not established clinical treatments.

Forestomach acidosis in six New World camelids

Forestomach acidosis was diagnosed in 2 llamas and 4 alpacas. All were young, group-housed, sexually intact males. Clinical signs included forestomach atony, lethargy, ataxia, diarrhea, and tachycardia. Forestomach distention was observed in only 1 llama. Clinicopathologic abnormalities included low forestomach fluid pH, hyperchloremia, hypokalemia, and metabolic acidosis. Although camelids differ from domestic ruminants in typical management practices and behavioral, anatomic, and physiologic characteristics, they are, nonetheless, susceptible to forestomach acidosis. Gastric fluid analysis was essential for an accurate diagnosis. Four of 6 camelids recovered after PO and IV treatment with alkalinizing agents and fluids, antibiotics, and thiamine.

Cisapride for gastroesophageal reflux disease: a placebo-controlled, double-blind study

OBJECTIVES

To evaluate the safety and efficacy of cisapride in patients with gastroesophageal reflux disease.

METHODS

Patients (N = 177) were randomized to double-blind treatment with cisapride (10 or 20 mg q.i.d.) or placebo for 12 wk. Efficacy was determined by pre- and poststudy endoscopies, symptom assessments by patient and physician, and Maalox consumption. Safety evaluations included vital signs, electrocardiograms, clinical laboratory tests, and reports of adverse events.

RESULTS

Cisapride 10 mg significantly reduced daytime and nighttime heartburn at 4 wk compared with placebo. Cisapride 20 mg reduced both daytime and nighttime heartburn at 4, 8, and 12 wk, compared with placebo, and was also significantly superior to the 10-mg dose at 12 wk. The percent of patients with endoscopic healing was significantly higher with cisapride 20 mg than with placebo [healing: 51 vs 36% (p < or = 0.044)]. Maalox usage declined significantly with cisapride 20 mg compared with placebo. No clinically significant changes in safety variables occurred with cisapride. The most frequently reported adverse events in the cisapride group were diarrhea, headache, and sinusitis.

CONCLUSIONS

Cisapride 10 and 20 mg q.i.d. were safe and well tolerated in a population of patients with mild-to-moderate gastroesophageal reflux disease. Both symptoms and endoscopic grade improved after 12 wk of treatment with cisapride 20 mg q.i.d.

Protection by almagate of ethanol-induced gastric mucosal damage in rats

The study was designed to analyse the protective effects of almagate on a model of gastric injury, ethanol-induced mucosal damage, in which acid plays little, if any, role. Pretreatment with almagate dose-dependently reduced the level of gastric damage induced by oral administration of 1 mL 100% ethanol. Administration of 12 mumol kg-1 alamagate 30 min before ethanol significantly reduced the area of mucosal damage by 65 +/- 10%, and the maximum level of inhibition (74 +/- 11%) was obtained with 150 mumol kg-1 almagate. Administration of higher doses of almagate (200-250 mumol kg-1) did not result in any further increase in the level of protection against ethanol-induced gastric damage. Administration of 1 mL 100% ethanol induces substantial damage to the gastric mucosa, with nearly 40% of the length of the section evaluated exhibiting deep necrotic and haemorrhagic damage. Pretreatment with almagate caused a significant diminution in all parameters of histological damage, whereas damage to the epithelial cell layer was only significantly reduced by pretreatment with the highest doses evaluated (25, 50 and 150 mumol kg-1). Administration of aluminium hydroxide did not modify ethanol-induced mucosal damage, even at doses containing concentrations of aluminium higher than those present in gastroprotective doses of almagate. Pretreatment with sucralfate, another aluminium containing compound, at doses of 250 mumol kg-1 protected the mucosa, although lower doses did not. The present study has shown that almagate prevents ethanol-induced gastric mucosal damage.(ABSTRACT TRUNCATED AT 250 WORDS)