Pharmacokinetics of propranolol and atenolol in patients after partial gastric resection: a comparative study

[Bariatric surgery and drugs: Review of the literature and Adverse Drug Reactions analysis in French National Pharmacovigilance Database]

INTRODUCTION

Bariatric surgery is the only treatment for severe obesity (BMI>35kg/m2) currently recognized as effective both in achieving tangible and lasting weight loss, and in improving obesity-related comorbidities such as type 2 diabetes, hypertension, and cardiovascular complications. Bariatric surgery, like any other surgery of the digestive tract, can have an impact on nutrient absorption, as well as on drug absorption. The literature on drug management in bariatric surgery patients concerned mainly of case reports and retrospective studies involving a small number of patients. No official guidelines are available.

METHODS

We conducted a literature search on the consequences of bariatric surgery in terms of drug bioavailability and/or effect. The Medline® (PubMed) database was searched using the following keywords: "bariatric surgery", "bioavailability", "gastric bypass", and "obesity". We completed this review with an analysis of reports of adverse drug reactions (ADRs) in post-bariatric surgery patients for obesity registered in the National pharmacovigilance database (PVDB). We selected all cases with the mention of "bariatric surgery and/or gastrectomy" as "medical history". After reading the cases, we excluded those in which the patient had undergone surgery for an indication other than obesity, where the route of administration was other than oral, and cases in which ADRs resulted from voluntary overdose, attempted suicide, allergy, switch to Levothyrox® new formulation, meningioma under progestative drugs, inefficacy related to generic substitution and medication error.

RESULTS

The literature search identified mainly "case report" about the impact of bariatric surgery on so-called "narrow therapeutic window" drugs. We identified 66 informative cases out of a total of 565 cases selected (11%) in the PVDB. Nevertheless, the information does not allow a clear relationship between the occurrence of the ADR and the influence of bariatric surgery.

CONCLUSION

There is a lack of official information and/or recommendations on medication use in subjects who have undergone bariatric surgery. Apart from under-reporting, ADRs reports remain largely uninformative. Health professional and patients would be awareness for improving, quantitatively and qualitatively the reporting of ADRs in this population.

Clinical insights into management options for recurrent type 2 diabetes and cardiovascular risk after metabolic-bariatric surgery

AIMS

Long-term clinical trials evaluating the effects of metabolic-bariatric surgery (MBS) on type 2 diabetes (T2D) demonstrate that a significant proportion of patients either fail to achieve remission or experience T2D recurrence over time. Furthermore, patients with recurrent T2D might require reinstitution of pharmacotherapy to control comorbidities (hypertension, dyslipidemia). This paper reviews therapeutic options in patients with T2D relapse.

DATA SYNTHESIS

Although presently there is no recommended pharmacological strategy, the available data support GLP-1 analogues (GLP-1a) as the most suitable option to control hyperglycemia post-MBS. Beside their efficacy in lowering glycemia and body weight while preserving lean mass, GLP-1a exert cardiovascular/renal-protection and are also safe and well tolerated in surgical patients. In addition, the s.c. route of administration of these medications circumvents the problem of changes in oral drugs bioavailability following MBS. Of note, the available data refers to liraglutide and needs to be confirmed with weekly GLP-1a agents. Information regarding the impact of MBS on the pharmacokinetics of lipid lowering and anti-hypertensive drugs is scarce and inconclusive. The findings indicate that timing from intervention is particularly important because of adaptive intestinal mechanisms.

CONCLUSIONS

The recurrence of T2D following MBS is a clinically relevant issue. GLP-1a therapy represents the best option to improve glycemic and weight control with good tolerability. Long-term clinical trials will clarify the impact of these drugs on cardiovascular outcomes. A close monitoring of MBS patients is advised to guide drug dosage adjustments and ensure the control of cardiovascular risk factors.

Clinical Pharmacokinetics of Propranolol Hydrochloride: A Review

BACKGROUND

Nobel laureate Sir James Black's molecule, propranolol, still has broad potential in cardiovascular diseases, infantile haemangiomas and anxiety. A comprehensive and systematic review of the literature for the summarization of pharmacokinetic parameters would be effective to explore the new safe uses of propranolol in different scenarios, without exposing humans and using virtual-human modeling approaches.

OBJECTIVE

This review encompasses physicochemical properties, pharmacokinetics and drug-drug interaction data of propranolol collected from various studies.

METHODS

Clinical pharmacokinetic studies on propranolol were screened using Medline and Google Scholar databases. Eighty-three clinical trials, in which pharmacokinetic profiles and plasma time concentration were available after oral or IV administration, were included in the review.

RESULTS

The study depicts that propranolol is well absorbed after oral administration. It has dose-dependent bioavailability, and a 2-fold increase in dose results in a 2.5-fold increase in the area under the curve, a 1.3-fold increase in the time to reach maximum plasma concentration and finally, 2.2 and 1.8-fold increase in maximum plasma concentration in both immediate and long-acting formulations, respectively. Propranolol is a substrate of CYP2D6, CYP1A2 and CYP2C19, retaining potential pharmacokinetic interactions with co-administered drugs. Age, gender, race and ethnicity do not alter its pharmacokinetics. However, in renal and hepatic impairment, it needs a dose adjustment.

CONCLUSION

Physiochemical and pooled pharmacokinetic parameters of propranolol are beneficial to establish physiologically based pharmacokinetic modeling among the diseased population.

Systematic review of drug bioavailability following gastrointestinal surgery

PURPOSE

Inter- and intraindividual pharmacokinetics variability in humans affects the way in which drugs act on the body. Gastrointestinal surgery has an impact on this variability and significantly alters the kinetics of drugs in post-surgical patients. The way in which pharmacokinetic profiles are modified depends on the type of operative procedure performed. The extent to which the absorption of different groups of drugs is affected varies according to the site and length of intestinal resections.

METHODS

A literature search was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Three databases were searched: MEDLINE, Embase, and the Cochrane Library. For each drug, potential changes in absorption were described, including recommendations extracted from the results of the studies and collected according to authors' criteria as practical conclusions, and grades of recommendation were determined by levels of evidence using the Oxford Centre for Evidence-Based Medicine scale.

RESULTS

Sixty-eight articles were collected during the selection process after the bibliographic search. The main outcomes for 60 drugs from the various studies were classified according to each type of surgery.

CONCLUSIONS

Modifications in the digestive tract secondary to gastrointestinal surgery may compromise the bioavailability of drugs. Decreased absorption surface, gastric emptying speed, and gastric pH alteration are factors to be taken into account in the management of pharmacological treatment after surgery. Evidence supported by data in clinical practice is scarce, but after studying the pharmacokinetic profile of some molecules, it is possible to offer recommendations for its adaptation to the patient's clinical situation.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

The pharmacokinetics of oral ketoprofen in patients after gastric resection

BACKGROUND

Total and partial gastric resection may affect the pharmacokinetics of drugs, especially orally administered a few days after surgery. Ketoprofen is a non-steroidal anti-inflammatory drug (NSAID) broadly used to treat postoperative pain, including patients after gastric resection. The aim of the research was to analyse the pharmacokinetics (PK) of orally administered ketoprofen in patients after gastrectomy.

METHODS

The research was carried out on two groups of patients after total (TG; Roux-Y procedure) and partial (PG; Billroth II procedure) gastrectomy. The patients in group TG (n=15; mean [SD] age 61.86 [14.15] years; and BMI 24.20 [3.73] kg/m²) and group PG (n=5; mean [SD] age 62.40 [16.80] years; and BMI 23.98 [3.45] kg/m²) received ketoprofen in a single oral dose of 100mg. The measurement of ketoprofen plasma concentrations was made by means of the HPLC (high performance liquid chromatography) method.

RESULTS

The PK parameters in group TG and PG were as follows: maximum plasma concentration (C_max), 3.42 [0.99] and 4.66 [0.81] mg/l (p=0.0220); area under the plasma concentration-time curve from zero to infinity (AUC_0-∞), 9.12 [2.78] and 9.17 [2.87] mg×h/ml (p=0.9734); area under the first moment curve from zero to the time of infinity (AUMC_0-∞), 25.95 [8.52] and 26.53 [11.43] mg×h²/l (p=0.9056); time to reach maximum concentration (t_max), 0.47 [0.25] and 0.55 [0.27] h (p=0.5327), respectively.

CONCLUSIONS

Lower concentrations of ketoprofen in patients after gastrectomy suggest that it might be necessary to apply higher dose of the analgesic.

Oral drug therapy following bariatric surgery: an overview of fundamentals, literature and clinical recommendations

Bariatric surgery is the most effective solution for severe obesity and obesity with comorbidities, and the number of patients going through bariatric surgery is rapidly and constantly growing. The modified gastrointestinal anatomy of the patient may lead to significant pharmacokinetic alterations in the oral absorption of drugs after the surgery; however, because of insufficient available literature and inadequate awareness of the medical team, bariatric surgery patients may be discharged from the hospital with insufficient instructions regarding their medication therapy. In this article, we aim to present the various mechanisms by which bariatric surgery may influence oral drug absorption, to provide an overview of the currently available literature on the subject, and to draw guidelines for the recommendations bariatric surgery patients should be instructed before leaving the hospital. To date, and until more robust data are published, it is essential to follow and monitor patients closely for safety and efficacy of their medication therapies, both in the immediate and distant time post-surgery.

The pharmacokinetics of the effervescent vs. conventional tramadol/paracetamol fixed-dose combination tablet in patients after total gastric resection

BACKGROUND

Tramadol/paracetamol is a fixed-dose combination prescribed for the relief of moderate to severe pain. The combination acts synergistically and guarantees the rapid onset of paracetamol and the prolonged analgesic effect of tramadol with good tolerability. These drugs are often used in various formulations in the treatment of patients with postoperative pain, e.g. after stomach resection. Gastrectomy leads to pathophysiological changes within the alimentary tract, which may affect the process of drug absorption. The aim of the research was an analysis of the pharmacokinetics of tramadol/paracetamol from effervescent and conventional tablets in patients after total gastrectomy.

METHODS

The research was carried out on patients after gastrectomy with Roux-en-Y reconstruction. The patients received two tramadol/paracetamol fixed-dose combination tablets in a single orally administered dose of 75/650 mg (2 × 37.5/325 mg). The patients were subjected to one of the two study drug group with: I. effervescent tablet (ET) (n = 14; mean [SD] age, 63.4 [10.1] years; weight, 75.5 [15.3]kg; and BMI, 26.0 [4.6]kg/m(2)) and II. conventional tablet (CT) (n = 12; mean [SD] age, 66.8 [7.7] years; weight, 79.8 [17.8]kg; and BMI, 27.4 [5.3]kg/m(2)). Blood samples were collected within 10 h after the drug administration. The plasma concentrations of tramadol and paracetamol were measured with validated HPLC (high-performance liquid chromatography) method with UV detection.

RESULTS

The comparison of the paracetamol and tramadol C(max) ratio for the ET group with that of the CT group gave ratios of 1.16 [90% confidence interval (CI) 1.06, 1.27] and 0.86 (90% CI 0.72, 1.02), respectively. The comparison of the paracetamol and tramadol AUC(0-t) ratio for the ET group with that of the CT group showed ratios of 0.99 (90% CI 0.88, 1.10) and 1.00 (90% CI 0.82, 1.22), respectively. The comparison of the difference for the effervescent and conventional formulation gave an estimated decrease in t(max) of 0.5 h for paracetamol and 0.13 h for tramadol.

CONCLUSIONS

In view of the changes in the pharmacokinetics of paracetamol and tramadol in the patients after gastric resection for both formulations compared the conventional tablet seems to be more appropriate due to the comparable rate of absorption of both substances, higher concentrations of tramadol and comparable exposure to paracetamol.

The influence of bypass procedures and other anatomical changes in the gastrointestinal tract on the oral bioavailability of drugs

The gastrointestinal (GI) tract plays an important role in the absorption of orally administered drugs. However, in some cases the anatomy of the GI tract is changed due to GI surgery, which has the potential of influencing drug bioavailability. In this review, we aim to compile, review, and comment the existing but sometimes fragmented scientific data regarding the impact of GI surgery on the oral bioavailability of drugs. Relevant reports were gathered through the PubMed database from database inception through January 2012. Drugs for which at least one trial or case report suggested a change in oral bioavailability or absorption caused by GI surgery are discussed in detail. Major methodological differences, such as study design, number of subjects and choice of reference group, were observed in the reported studies. Predicting the impact of GI surgery on the oral bioavailability was therefore difficult to perform, even the most sophisticated classification systems could not be used for predicting purposes.

Cardiopulmonary bypass alters the pharmacokinetics of propranolol in patients undergoing cardiac surgery

The pharmacokinetics of propranolol may be altered by hypothermic cardiopulmonary bypass (CPB), resulting in unpredictable postoperative hemodynamic responses to usual doses. The objective of the present study was to investigate the pharmacokinetics of propranolol in patients undergoing coronary artery bypass grafting (CABG) by CPB under moderate hypothermia. We evaluated 11 patients, 4 women and 7 men (mean age 57 +/- 8 years, mean weight 75.4 +/- 11.9 kg and mean body surface area 1.83 +/- 0.19 m(2)), receiving propranolol before surgery (80-240 mg a day) and postoperatively (10 mg a day). Plasma propranolol levels were measured before and after CPB by high-performance liquid chromatography. Pharmacokinetic Solutions 2.0 software was used to estimate the pharmacokinetic parameters after administration of the drug pre- and postoperatively. There was an increase of biological half-life from 4.5 (95% CI = 3.9-6.9) to 10.6 h (95% CI = 8.2-14.7; P < 0.01) and an increase in volume of distribution from 4.9 (95% CI = 3.2-14.3) to 8.3 l/kg (95% CI = 6.5-32.1; P < 0.05), while total clearance remained unchanged 9.2 (95% CI = 7.7-24.6) vs 10.7 ml min(-1) kg(-1) (95% CI = 7.7-26.6; NS) after surgery. In conclusion, increases in drug distribution could be explained in part by hemodilution during CPB. On the other hand, the increase of biological half-life can be attributed to changes in hepatic metabolism induced by CPB under moderate hypothermia. These alterations in the pharmacokinetics of propranolol after CABG with hypothermic CPB might induce a greater myocardial depression in response to propranolol than would be expected with an equivalent dose during the postoperative period.