China
Africa
Explore chapters and articles related to this topic
Paediatric clinical pharmacology
Published in Evelyne Jacqz-Aigrain, Imti Choonara, Paediatric Clinical Pharmacology, 2021
Evelyne Jacqz-Aigrain, Imti Choonara
In order to attain a therapeutic regimen, a loading dose may be employed (Figure 4a). This will be determined by the volume of distribution and the target concentration. In general, for a drug that is dosed at its half-life (i.e., x=t½; a common practice), the steady state concentration will be approximately double that attained with a single dose and, in such circumstances, the loading dose would often be about double the steady-state dose. However, multi-compartment kinetics may make the calculations more complicated. Steady-state concentration usually refers to the mean drug concentration, although Cmax and Cmin can also be defined at steady state. Some drugs will have steady-state concentrations that are different to what would be predicted from a single dose. An example would be lamotrigine, which induces its own metabolism and hence, its clearance increases with time.
Fundamentals of Drug Therapy
Published in Stanley R. Resor, Henn Kutt, The Medical Treatment of Epilepsy, 2020
Each drug administered sooner or later reaches a steady state, a more or less constant level which is achieved by the particular daily dose administered. When a total daily dose is changed, the pharmacokinetic rule is simple: after every dose change it takes five half-lives to reach 97% of a new steady-state plasma drug level. Only after the new steady-state level is reached can drug efficacy be evaluated. For example, accurate evaluation of PB’s efficacy within a few days after a dose change is not possible. The half-life of PB may be 96 hours or more, and 3 weeks will often be required to reach a new steady-state level. With CBZ or VPA, however, a new steady state will be achieved within a few days, and the efficacy of the drug can be more rapidly determined. Of the AEDs most commonly used, only CBZ and VPA, and to some extent PRM, have short half-lives, which allow relatively rapid achievement of a steady-state level after a dose change.
Prescribing and the older patient in the community
Published in David Beales, Michael Denham, Alistair Tulloch, Community Care of Older People, 2018
Pharmacokinetics (what the body does to the drug) changes with increasing age. Drug absorption from the gut is more or less unaltered but distribution of the drug within the body can change due to an increase in body fat and reduced lean-body mass seen in old age. The result is that the potential depot for fat-soluble drugs is increased and therefore the half-life lengthened. Many drugs are carried by albumin, the concentration of which often decreases with age, and therefore the total amount of bound drug is reduced. However in the ‘steady-state’ situation the therapeutic effect of the drug is usually little changed.
Therapeutic drug monitoring-guided dosing for pediatric cystic fibrosis patients: recent advances and future outlooks
Published in Expert Review of Clinical Pharmacology, 2023
Siân Bentley, Jamie Cheong, Nikesh Gudka, Sukeshi Makhecha, Simone Hadjisymeou-Andreou, Joseph F Standing
In individual circumstances, TDM has been useful to guide antibiotic dosing when using multiple antibiotic combinations to achieve a reduced MIC (from ≥256mcg/ml for individual antibiotics down to 8 mcg/ml when used in combination). This was demonstrated in a child with CF with resistant Stenotrophomonas maltophilia, treated with aztreonam and ceftazidime/avibactam [43]. Based on TDM resulting in a dose increase, and change to a continuous infusion of ceftazidime, 100% T>MIC was achieved for both aztreonam and ceftazidime. Drug levels were taken at steady state. For intermittent infusions, this was immediately after the infusion, then 1 hour later; for continuous infusions this was after a minimum of 8 hours. Despite clinical improvement and achieving target PK/PD parameters, lung function did not recover, highlighting that although TDM is useful, it should be used in conjunction with other clinical investigations. Ceftazidime TDM was also used to achieve positive outcomes in an adult CF patient treated with ceftazidime/avibactam and trimethoprim/sulfamethoxazole for Burkholderia cepacia colonization [44]. Ceftazidime trough levels were maintained above the MIC (2 mg/L) and the patient was discharged from the ward after 2 weeks with surveillance cultures 1 month later reporting that the MIC remained unchanged. Adequate drug levels ensured minimal emergence of resistant strains.
Experimental design, formulation, and in-vivo evaluation of novel anticoagulant Rivaroxaban loaded cubosomes in rats model
Published in Journal of Liposome Research, 2023
Hadeer A. El-Hashemy, Abeer Salama, Amira Rashad
When it comes to systemic drug delivery from pharmaceutical products, the oral route is the most often used method of administration. Due to its simplicity in administration, patient acceptability, and economical production procedure, the oral route is regarded as the most practical and secure method (Reddy and Himavarsha 2018, Allen et al.2006). The typical oral dose may have negative effects on the plasma drug concentrations. Variations in the metabolism and/or absorption may result in changes in the drug’s plasma concentration. Additionally, a non-steady state of drug concentration may occur with repeated dosing (Gaur et al.2014). The vesicular systems offer a controlled delivery strategy and extend the drug’s duration in the bloodstream. Nanovesicles made of lipids improve medication absorption where the drug release profiles are noticeably altered when such drug is dissolved, confined, encapsulated, or linked to a nanoparticle matrix. The vesicular systems provide a controlled drug delivery process and prolong the residence time of the drug in general circulation (Pouton and Porter 2008). One of the nanovesicles drug delivery devices that will be examined in this work is the cubosome (El-Laithy et al.2018).
Audit of clinical and laboratory parameters of hemoglobin SS patients in a Nigerian teaching hospital
Published in Annals of Medicine, 2022
Titilola Stella Akingbola, Oladapo Wale Aworanti, Sunday Peter Ogundeji
This was a descriptive cross-sectional study of 90 adult HbSS patients diagnosed with hemoglobin electrophoresis who are being followed up at the Hematology department of the Teaching Hospital in Nigeria between January and June 2017. They were classified into three groups based on their clinical presentations: steady state, hemolytic and vaso-occlusive crises with 30 individuals in each group. Steady state patients presented for routine follow up visits at the Hematology Out-patient clinic while the other two groups presented in either Hemolytic or Vaso occlusive crisis to either the Hematology Day-care Unit (HDCU) or the emergency department of the hospital. Steady state is defined as stable health state in HbSS patients who did not have bone pain or any other crisis and no blood transfusions in the previous 2 months [10]. Vaso-occlusive crisis (VOC) group: Vaso-occlusive crisis is defined as the occurrence of pain in the extremities, back, chest (ribs, sternum) that lasted for at least 2 h, led to a hematology day-care unit visit, and could not be explained except by sickle cell disease without features of hemolysis [11,12]. Hemolytic crisis is defined as ≥3% reduction in hematocrit, marked reticulocytosis, circulating nucleated red blood cells, polychromasia, unconjugated bilirubinemia and increased urobilinogen in sickle cell anemia [11,12]. The individuals with concurrent overt infection, pregnancy, other SCD, those with concurrent crises and on hydroxyurea (HU) were excluded. Those on Hydroxyurea were excluded due to low penetration of HU in our environment.