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Acute coronary syndromes
Published in Henry J. Woodford, Essential Geriatrics, 2022
Following a diagnosis of ACS, an initial loading dose of aspirin is given (i.e. 300 mg orally), followed by 75 mg daily maintenance (unless there are contraindications).2 In addition, a P2Y12 inhibitor (i.e. ticagrelor, clopidogrel or prasugrel) is given but, for people having primary PCI, the start of this medication may be delayed until immediately after the intervention. A loading dose is required, followed by maintenance dose therapy.
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.
Anticoagulant Therapy
Published in Hau C. Kwaan, Meyer M. Samama, Clinical Thrombosis, 2019
Hau C. Kwaan, M. M. Samama, A. R. Kher
The alteration of biologic activity following coumarin administration is dependent on the normal catabolic rate of the respective clotting proteins.151–153 This is fastest with Factor VII, occurring in about 20 h, followed by Factor IX in 65 h, Factor X in 130 h, and the slowest, Factor II, requiring 8 d. The customary prothrombin time monitoring, sensitive to changes in Factors VII and X activity, will be prolonged as early as the second day of treatment, but will not reach a plateau until the fourth or fifth day. Since the rate of change in the biologic activities depends entirely on the catabolic rate of the clotting factors, the speed of initial anticoagulation by warfarin would not be altered by giving a higher initial loading dose. The loading dose can only produce a higher plasma level of the drug — potentially leading to a dangerous overdose in some patients — and is not recommended.151,152
Management of immune thrombotic thrombocytopenic purpura with caplacizumab: a Canadian, single-centre, real-world experience
Published in Platelets, 2023
Brandon Tse, Megan Buchholz, Katerina Pavenski
As caplacizumab is not publicly funded in Canada, it was obtained through compassionate supply. The reason for initiation depended on the individual patient context; these included refractory disease (5/11) and upfront therapy, which included previous refractoriness (1/11), significant end organ damage at presentation (for example, focal neurological deficit; 4/11), and other (1/11). Caplacizumab was initiated for a median of 6 days after admission (IQR 2.5–8.0 days) and continued for a median of 26 days (IQR 14–33 days). Most patients (8/11, 73%) received an intravenous loading dose. TPE was discontinued for a median of 4 days (IQR 3–6 days) after initiation of caplacizumab. Due to concerns about bleeding risk, DVT prophylaxis was only initiated in 1/11 patients while on treatment. Caplacizumab discontinuation was based on a combination of clinical remission and ADAMTS13 activity, which was routinely monitored until >10%. One patient (Patient 1) elected to discontinue treatment after 65 days of treatment, while in clinical remission but with persistently low ADAMTS13 activity.
Relugolix in the management of prostate cancer
Published in Expert Review of Anticancer Therapy, 2022
Kamal Kant Sahu, Nishita Tripathi, Neeraj Agarwal, Umang Swami
Cohort 3 and 4 dose regimens aimed to evaluate the safety profile of the 160‐mg maintenance dose and 360‐mg loading dose. After the completion of 28 days, patients from cohorts 1 and 2 in part A were enrolled in part B of the study (expansion phase). In Part B, patients were randomized 1: 1 to 2 cohorts as mentioned below: Cohort 1: 320 mg loading dose on day 1 →80 mg daily maintenance dose till week 48.Cohort 2: 320 mg loading dose on day 1 →120 mg daily maintenance dose till week 48.
Prescribing patterns of vitamin D and analogues in a private healthcare patient population in South Africa
Published in South African Journal of Clinical Nutrition, 2022
Angela Ann Morris-Paxton, Ilse Truter
There is a lack of consensus on the appropriate vitamin D supplement dosage.1 Although the higher dose of 50 000 IU capsules or tablets appears to be the predominant prescribing practice for South Africa, not all researchers agree that this is necessary. One study found that a single loading dose followed by a low daily maintenance dose was equally effective with the possibility of fewer high-dose risks.36 Another study by Kearns et al. (2014), however, found that daily intake may be difficult to comply with and larger single doses were more effective for eradication of vitamin D deficiency.58 They also found that single vitamin D3 doses in excess of 300 000 IU are most effective at improving vitamin D status and suppressing compensatory parathyroid hormone concentrations, which draw calcium from bones, although gastrointestinal complaints were reported by a few patients at higher doses of vitamin D intake.