Browsing by Author "Divac, N. (23003936900)"

ATP-binding cassette (ABC)-transporters, such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs) and breast cancer resistance protein (BCRP/ABCG2) transport numerous drugs thus regulating their absorption, distribution and excretion. Angiotensin receptor type 1 blockers (ARBs), used to treat hypertension and heart failure, are commonly administered in combination therapy. However, their interaction potential is not well studied and their effect on ABC-transporters remains elusive. The study therefore aimed to elucidate the effect of various ARBs (telmisartan, candesartan, candesartan-cilexetil, irbesartan, losartan, olmesartan, olmesartan-medoxomil, eprosartan) on ABC-transporter activity in vitro. P-gp inhibition was assessed by calcein assay, BCRP inhibition by pheophorbide A efflux assay, and MRP2 inhibition by a MRP2 PREDIVEZ™ Kit. Induction of P-gp, BCRP and MRP2 was assessed by real time reverse transcriptase polymerase chain reaction and for P-gp also in a functional assay. Telmisartan was identified as one of the most potent inhibitors of P-gp currently known (IC 50 = 0.38±0.2 μM for murine P-gp) and it also inhibited human BCRP (IC50 = 16.9±8.1 μM) and human MRP2 (IC 50 = 25.4±0.6 μM). Moreover, the prodrug candesartan-cilexetil, but not candesartan itself, significantly inhibited P-gp and BCRP activity. None of the compounds tested induced mRNA transcription of P-gp or BCRP but eprosartan and olmesartan induced MRP2 mRNA expression. In conclusion, telmisartan substantially differed from other ARBs with respect to its potential to inhibit ABC-transporters relevant for drug pharmacokinetics and tissue defense. These findings may explain the known interaction of telmisartan with digoxin and suggest that it may modulate the bioavailability of drugs whose absorption is restricted by P-gp and possibly also by BCRP or MRP2. Copyright © 2010 John Wiley & Sons, Ltd.

ATP-binding cassette (ABC)-transporters, such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs) and breast cancer resistance protein (BCRP/ABCG2) transport numerous drugs thus regulating their absorption, distribution and excretion. Angiotensin receptor type 1 blockers (ARBs), used to treat hypertension and heart failure, are commonly administered in combination therapy. However, their interaction potential is not well studied and their effect on ABC-transporters remains elusive. The study therefore aimed to elucidate the effect of various ARBs (telmisartan, candesartan, candesartan-cilexetil, irbesartan, losartan, olmesartan, olmesartan-medoxomil, eprosartan) on ABC-transporter activity in vitro. P-gp inhibition was assessed by calcein assay, BCRP inhibition by pheophorbide A efflux assay, and MRP2 inhibition by a MRP2 PREDIVEZ™ Kit. Induction of P-gp, BCRP and MRP2 was assessed by real time reverse transcriptase polymerase chain reaction and for P-gp also in a functional assay. Telmisartan was identified as one of the most potent inhibitors of P-gp currently known (IC 50 = 0.38±0.2 μM for murine P-gp) and it also inhibited human BCRP (IC50 = 16.9±8.1 μM) and human MRP2 (IC 50 = 25.4±0.6 μM). Moreover, the prodrug candesartan-cilexetil, but not candesartan itself, significantly inhibited P-gp and BCRP activity. None of the compounds tested induced mRNA transcription of P-gp or BCRP but eprosartan and olmesartan induced MRP2 mRNA expression. In conclusion, telmisartan substantially differed from other ARBs with respect to its potential to inhibit ABC-transporters relevant for drug pharmacokinetics and tissue defense. These findings may explain the known interaction of telmisartan with digoxin and suggest that it may modulate the bioavailability of drugs whose absorption is restricted by P-gp and possibly also by BCRP or MRP2. Copyright © 2010 John Wiley & Sons, Ltd.

Objectives: The use of drugs in an off label or unlicensed manner to treat children is a widespread phenomenon in Europe and the United States. The incidence of unlicensed and off label prescribing in paediatric cardiology practice has not been studied to date. This study was designed to assess the extent and nature of off label and unlicensed drug use in paediatric cardiology inpatients. Methods: In a prospective study, drug prescriptions in a paediatric cardiology ward were reviewed during a 2-year period. Data were collected and analyzed by special software created for this purpose. Results: The children (n=544) studied varied in age from 4 h to 18 years. One or more off label and unlicensed prescriptions were given to 414 (76%) patients. Of the 2,130 prescriptions given during the 2-year period, more than one-half were unlicensed (11%) or off label (47%). While children aged 2-11 years received most of the unlicensed drug prescriptions (17%), neonates, who did not receive unlicensed drugs, led (64%) in the use of off label drugs. Conclusions: This study showed that the problem of off label and unlicensed drug use also exists in paediatric cardiology. The findings imply that the phenomenon of off label and unlicensed use of drugs in children can be correlated with the deficiency of paediatric drug formulations on the global market and insufficient data from clinical studies which must be performed to confirm the efficacy and safety of drugs in the paediatric population. Therefore, efforts to improve paediatric labelling are important and need the full support of all involved. © Springer-Verlag 2005.

Objectives: The use of drugs in an off label or unlicensed manner to treat children is a widespread phenomenon in Europe and the United States. The incidence of unlicensed and off label prescribing in paediatric cardiology practice has not been studied to date. This study was designed to assess the extent and nature of off label and unlicensed drug use in paediatric cardiology inpatients. Methods: In a prospective study, drug prescriptions in a paediatric cardiology ward were reviewed during a 2-year period. Data were collected and analyzed by special software created for this purpose. Results: The children (n=544) studied varied in age from 4 h to 18 years. One or more off label and unlicensed prescriptions were given to 414 (76%) patients. Of the 2,130 prescriptions given during the 2-year period, more than one-half were unlicensed (11%) or off label (47%). While children aged 2-11 years received most of the unlicensed drug prescriptions (17%), neonates, who did not receive unlicensed drugs, led (64%) in the use of off label drugs. Conclusions: This study showed that the problem of off label and unlicensed drug use also exists in paediatric cardiology. The findings imply that the phenomenon of off label and unlicensed use of drugs in children can be correlated with the deficiency of paediatric drug formulations on the global market and insufficient data from clinical studies which must be performed to confirm the efficacy and safety of drugs in the paediatric population. Therefore, efforts to improve paediatric labelling are important and need the full support of all involved. © Springer-Verlag 2005.

Aim: This study analyzed the prevalence of hypertension and the pattern of antihypertensive treatment before and after kidney transplantation. Patients and methods: The prevalence of hypertension and the class and daily dosage load of antihypertensive medications were analyzed in 116 patients before kidney transplantation and 1, 6, and 12 months after transplantation (67.2 % males, mean age 45.9 ± 11.4 years). Two patients died and eight had the allograft explanted, leaving 106 patients in the final analysis. Blood pressure (BP) was recorded on the day of transplantation and at every follow-up; it was considered uncontrolled at values > 130/80 mmHg. Results: The prevalence of uncontrolled BP was significantly reduced after kidney transplantation (63.2 % before transplantation vs. 54.7, 41.5, and 25.5 % at the 1‑, 6‑, and 12-month follow-up, respectively, p < 0.001 for all). The number of prescribed antihypertensives did not change significantly during the follow-up (1.96 ± 1.03 before transplantation vs. 2.01 ± 0.88, 1.71 ± 0.78, and 1.73 ± 0.73 at the 1‑, 6‑, and 12-month follow-up, respectively, p > 0.05 for all). There was a significant decrease in antihypertensive drug load during the follow-up (1.08 ± 1.3 end of the study vs. 2.05 ± 2.32 before transplantation, p < 0.008). Before kidney transplantation, angiotensin-converting enzyme (ACE) inhibitors were most commonly prescribed (52.8 %), while after surgery β‑blockers gained prevalence (59.4–63.2 %). Mean arterial pressure decline correlated with an improvement of graft function. Conclusion: The prevalence of uncontrolled BP and the antihypertensive drug dosage load reduced significantly after kidney transplantation. β‑blockers were used more frequently than ACE inhibitors after kidney transplantation. © 2016, Springer Medizin Verlag.

OBJECTIVE: Ketamine and magnesium, both N-methyl-D-aspartate (NMDA) receptor antagonists, enhance the antinociceptive effects of opioid analgesics in different animal models of pain, as well as in humans. This study aimed at evaluating whether magnesium sulphate added to morphine-ketamine combination produces a higher level of analgesia. MATERIALS AND METHODS: Analgesic activity was assessed by tail-immersion test in male Wistar rats (200-250 g). RESULTS: Magnesium sulphate (0.5-60 mg/kg, s.c.) and ketamine (5-30 mg/kg, i.p.) administered alone did not produce any effect. Magnesium sulphate (5 and 60 mg/kg) and ketamine (5 and 30 mg/kg) increased the antinociceptive effect of morphine (2.6 mg/kg, i.p.). Magnesium sulphate (5 mg/kg) increased the antinociceptive effect of the morphine (2.6 mg/kg)-ketamine (2.5 or 5 mg/kg) combination when magnesium sulphate was added to morphine after, and not before ketamine. It is also demonstrated that magnesium sulphate prolonged the duration of the antinociceptive effect of the morphine-ketamine combination. Low dose of morphine (2.6 mg/kg), ketamine (5 mg/kg) and magnesium sulfate (5 mg/kg) given together did not cause motor impairment that could be verified on a rotarod test.The antinociceptive effect of the triple combination was readily antagonized with naloxone (3 mg/kg, s.c.), a nonselective antagonist of opioid receptors, indicating that the effect is mediated via opioid receptors. CONCLUSIONS: This study revealed that the efficacy of the morphine-ketamine-magnesium sulphate combination in tail-immersion test in rats is influenced by the order of medication administration; a higher level of activity is demonstrated only when ketamine is added to morphine before magnesium sulphate.