Biomedical subjects

Riberto Garcia

Publications and source records attributed to Riberto Garcia.

4 recordsLinked to original sources

PubMed2005

Concentration-controlled use of sirolimus associated with reduced exposure of cyclosporine in black recipients of primarily living renal allograft donors: 12-month results.

AIM: This study was designed to identify optimal therapeutic sirolimus (SRL) concentrations in black kidney transplant recipients on reduced cyclosporine (CsA) exposure and prednisone. METHODS: Seventy patients (64 living/six deceased) received CsA (8-10 mg/kg/d), prednisone, and 15 mg loading dose followed by 5-mg fixed doses of SRL till day 7 when they were randomized to maintain SRL trough concentrations (high-performance liquid chromatography) of 8-12 (GI = 34) or 15-20 (GII = 36) ng/mL. RESULTS: Mean CsA concentrations were 109 +/- 53 vs. 89 +/- 41 ng/mL and 75 +/- 54 vs. 60 +/- 35 ng/mL (ns) at 2 and 6 months. Accordingly, mean SRL trough concentrations were 12.4 +/- 6.1 vs. 20.0 +/- 9.5 ng/mL (p < 0.001) and 10.8 +/- 5.8 vs. 18.0 +/- 6.1 ng/mL (p < 0.001). The incidence of biopsy-proven acute rejection [13% (GI: 18% vs. GII: 8%, ns)], graft loss or death was 16% (GI: 21% vs. GII: 11%, ns]. There were no deaths and three graft losses (GI = 1; GII = 2). Creatinine clearance was higher in GI (64.5 +/- 17 vs. 54.4 +/- 14.7 mL/min, p = 0.011). The incidence of post-transplant diabetes mellitus was 13% and no CMV disease was observed. CONCLUSION: In black recipients of primarily living renal allograft donors reduced CsA exposure and SRL concentration-controlled regimens produced low incidences of acute rejection, post-transplant diabetes mellitus and CMV disease, with no significant impairment in graft function.

Adult↗

PubMed2004

An open-label randomized trial of the safety and efficacy of sirolimus vs. azathioprine in living related renal allograft recipients receiving cyclosporine and prednisone combination.

BACKGROUND: The ability of sirolimus (SRL), in combination with reduced exposure of cyclosporine, was investigated to prevent acute rejection and associated side effects. METHODS: Between June 1999 and February 2000, 70 recipients of primary one-haplotype living-related donor renal allografts were randomized to receive SRL (2 mg/d) or azathioprine (AZA) (2 mg/kg/d) combined with cyclosporine and prednisone. The primary end-point was a composite of first occurrence of biopsy-confirmed acute rejection, graft loss, or death during the first 3 months after transplantation. RESULTS: From week 4 to month 12, SRL patients received lower cyclosporine (week 4: 364 mg/d vs. 455 mg/d, p = 0.004; month 12: 195 mg/d vs. 255 mg/d, p = 0.038) doses and showed lower cyclosporine concentrations (week 4: 247 ng/mL vs. 309 ng/mL, p = 0.04; month 12: 143 ng/mL vs. 188 ng/mL, p = 0.045). Compared with AZA, SRL patients showed reduced 3-month primary end point (0% vs. 17.1%, p = 0.025), and reduced incidence of biopsy-confirmed acute rejection at 3 months (0% vs. 14.3%, p = 0.01) but not at 12 months (11.4% vs. 14.3%, NS). Mean creatinine at 12 months were not different (1.8 +/- 0.6 vs. 1.6 +/- 0.6, p = 0.23). Hyperlipidemia was the only adverse event more frequent among SRL patients (49% vs. 17%, p = 0.01). There were no differences in infections and no malignancies in both groups. CONCLUSIONS: The combination of 2 mg fixed doses of SRL, reduced cyclosporine exposure and prednisone was associated with a low incidence of acute rejection and did not result in significantly impaired graft function compared with patients receiving AZA, standard doses of cyclosporine and prednisone.

Adult↗

PubMed2003

Time-dependent changes in cyclosporine exposure: implications for achieving target concentrations.

This study analyzed early changes in trough blood cyclosporine concentrations and cyclosporine exposures after kidney transplantation. Seventy-two patients who received cyclosporine-based immunosuppressive therapy were intensively monitored (C0) during the first 6 months after transplantation. Full pharmacokinetic studies were performed at day 4, and months 2, 3, and 6 after transplantation. Mean steady-state, dose-adjusted trough cyclosporine blood concentrations increased from 1.1+/-0.60 (day 7) to 2.0+/-1.20 ng/ml per mg (day 30, P<0.01). Steady-state, dose-adjusted cyclosporine exposure parameters (C0, Cmax, AUC, Cavg, and C12) were significantly lower at day 4 than at months 2, 3, and 6 after transplantation ( P<0.01). Initial cyclosporine doses produced target concentrations in only 30% of the patients at day 3. C2 was the single concentration that showed high and consistent correlation with serial AUC measurements ( r(2)>/=0.76). The incidence of biopsy-proven acute rejection was 20.5% and was not associated with ethnicity, HLA mismatch, adjunctive therapy, or blood trough cyclosporine concentrations below 200 ng/ml at day 3. Significant time-dependent increases in steady-state cyclosporine exposure occur during the first month after kidney transplantation. Due to the low relative bioavailability early after surgery, higher doses and more frequent cyclosporine dose adjustments are necessary to produce target exposures early after transplantation.

Adult↗

PubMed2002

The impact of ethnic miscegenation on tacrolimus clinical pharmacokinetics and therapeutic drug monitoring.

UNLABELLED: The impact of ethnic miscegenation on tacrolimus clinical pharmacokinetics and therapeutic drug monitoring. We sought to determine the influence of ethnic miscegenation on tacrolimus pharmacokinetics and trough concentrations during the first 6 months after transplantation. METHODS: Tacrolimus concentrations were measured in blood samples obtained from 22 transplant recipients during the first week of transplant, within pharmacokinetic profiles, and throughout the first 6 months post-transplant, using the Pro Tac II ELISA method. Pharmacokinetic parameters and between- and within-subject blood concentration variability were compared stratifying the total population in two distinct ethnic groups of white (W) and non-white (NW) patients, according to a stringent criterion. RESULTS: Between-subject variability in dose-adjusted concentrations during dosing interval varied from 38.8 to 69.5%. Compared with W patients, NW patients showed higher variability in blood tacrolimus concentrations during dosing interval (37.40 +/- 5.64 vs. 56.95 +/- 11.49, p < 0.001) and lower drug exposures (AUC: 229.4 +/- 55.5 vs. 66.9 +/- 67.1 ng x h/mL, p=0.036). The correlation coefficients (r2) between C0, C12 or Cmax and AUC were 0.83, 0.91 and 0.5, respectively. An equation derived from early time concentrations (C0, C1.5 and C4) accounted for 94% of the variability observed in AUC. Compared with W patients, a higher proportion of tacrolimus blood determinations during the first week were below 10 nug/mL in NW patients (24% vs. 62%, p=0.028). Tacrolimus absorption increased from week 1-4 (1.1 +/- 0.53 vs. 1.73 +/- 0.97 nug/mL/mg, p < 0.0001) but was still showed high between- (41.6-70.4%) and within-subject (18.2-32.5%) variability, regardless of ethnicity, after stabilization. CONCLUSION: Non-white patients show higher tacrolimus variability and lower drug exposures after transplantation compared with W patients. Therefore, higher initial tacrolimus doses and intensive monitoring are recommended when administering tacrolimus-based immunosupressive therapy to NW patients of this transplant population.

Adult↗