Int J Clin Pharm Th
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Int J Clin Pharm Th · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialEffects of different combinations of H2 receptor antagonist with gastrokinetic drugs on gastric fluid pH and volume in children--a comparative study.
In a prospective double-blind randomized study, 100 American Society of Anesthesiologists classification I (ASAI) children (aged 2-8 years) were allocated randomly to receive 1 of the 5 different oral premedicant combination, 2 hours before surgery. Group I (control) received placebo premedication, group II (RM) received ranitidine 2 mg/kg-1 with metoclopramide 0.2 mg/kg-1, group III (RD) received ranitidine 2 mg/kg-1 with domperidone 0.3 mg/kg-1, group IV (FM) received famotidine 0.5 mg/kg-1 with metoclopramide 0.2 mg/kg-1, and group V (FD) received famotidine 0.5 mg/kg-1 with domperidone 0.3 mg/kg-1. After tracheal intubation, gastric fluid was aspirated and analyzed for pH and total fluid volume. ⋯ Mean gastric volume was significantly lower in RM, RD, FM, and FD groups (< 0.24 ml/kg-1) as compared to control group (0.5 ml/kg-1) (p < 0.01). Famotidine was found to be more effective in increasing gastric pH (p < 0.01) and decreasing volume (p < 0.05) as compared to ranitidine. No difference was found between metoclopramide and domperidone in increasing gastric pH and reducing gastric volume.
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Int J Clin Pharm Th · Oct 1997
ReviewBasic concepts of pharmacokinetic/pharmacodynamic (PK/PD) modelling.
Pharmacokinetic (PK) and pharmacodynamic (PD) information from the scientific basis of modern pharmacotherapy. Pharmacokinetics describes the drug concentration-time courses in body fluids resulting from administration of a certain drug dose, pharmacodynamics the observed effect resulting from a certain drug concentration. The rationale for PK/PD-modelling is to link pharmacokinetics and pharmacodynamics in order to establish and evaluate dose-concentration-response relationships and subsequently describe and predict the effect-time courses resulting from a drug dose. ⋯ Four basic attributes may be used to characterize PK/PD-models: First, the link between measured concentration and the pharmacologic response mechanism that mediates the observed effect, direct vs. indirect link; second, the response mechanism that mediates the observed effect, direct vs. indirect response; third, the information used to establish the link between measured concentration and observed effect, hard vs. soft link; and fourth, the time dependency of the involved pharmacodynamic parameters, time-variant vs. time-invariant. In general, PK/PD-modelling based on the underlying physiological process should be preferred whenever possible. The expanded use of PK/PD-modelling is assumed to be highly beneficial for drug development as well as applied pharmacotherapy and will most likely improve the current state of applied therapeutics.
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A major goal of current pain research is to develop scientifically-based guidelines to optimize selection of analgesic drug doses and control pain. Numerous clinical studies have shown that the drug dose required to effectively alleviate pain is often highly variable, both between patients and between pain episodes in individual patients. This high variability makes it difficult to predict appropriate dosing regimens that will adequately control pain in the individual patient. ⋯ This review examines the available pharmacokinetic-pharmacodynamic (PK/PD) data for selected opioid and nonopioid analgesics. Even though most analgesics are used clinically in multiple doses, the majority of PK/PD studies conducted to date evaluate single dose effects. Further studies with multiple doses are required to evaluate the validity of PK/PD relationships defined from single dose studies.