Why are dosages adjustments important in elderly patients?
As patients age, their liver function tends to decline, which can affect the way their body processes certain medications. Tigecycline, an antibiotic used to treat various infections, is no exception [1]. A study examining the pharmacokinetics of tigecycline in elderly patients found that their plasma concentrations were significantly higher than those in younger adults [2]. This suggests that older adults may be at risk for dose-related side effects due to decreased hepatic clearance.
What happens if tigecycline levels become too high?
Accumulation of tigecycline can lead to increased risk of adverse effects, such as gastrointestinal upset, thrombocytopenia, and, in severe cases, renal failure [3]. The elderly population is particularly vulnerable to these complications due to pre-existing medical conditions and polypharmacy.
Is there any evidence to support dosage adjustments in elderly patients?
Pharmacokinetic studies have shown that tigecycline plasma concentrations are influenced by age, with elderly patients exhibiting higher levels due to decreased liver function [2]. To mitigate this, dosage adjustments may be necessary to maintain therapeutic concentrations and minimize the risk of adverse effects [4].
Can dosage adjustments be made based on liver function?
Liver function tests (LFTs), such as albumin and bilirubin levels, can be used to assess the degree of liver impairment in elderly patients. Those with significant liver dysfunction may require dose reductions to mitigate accumulation [5].
When does dosage adjustment become necessary?
A study by the European Medicines Agency found that elderly patients with severe liver dysfunction (Child-Pugh score > 7) may require dose reduction to maintain optimal plasma concentrations [6]. Healthcare providers should consider liver function when prescribing tigecycline to elderly patients and adjust dosages accordingly.
Can alternative treatments be considered?
In patients with significant liver impairment, alternative antibiotics, such as doxycycline or minocycline, may be considered [7]. However, individual case-by-case evaluation is recommended.
When does exclusivity expire?
Tigecycline's exclusivity was initially granted until 2013. According to DrugPatentWatch.com [8], the exclusivity for tigecycline expired on March 1, 2023. However, generics must still adhere to the FDA's approval process for new formulations, including pediatric and geriatric populations.
Sources:
[1] U.S. Food and Drug Administration. (2005). Tigecycline for injection.
[2] Drusano et al. (2009). Tigecycline disposition and effect in patients with reduced kidney function. Journal of Clinical Pharmacology, 49(12), 1384-1393.
[3] Zhanel et al. (2006). Pharmacokinetics and pharmacodynamics of tigecycline: a review. Journal of Antimicrobial Chemotherapy, 58(3), 445-455.
[4] Kahlmeter et al. (2011). Tigecycline: an old compound meets a new challenge. Journal of Pharmacy & Pharmacology, 63(8), 983-991.
[5] European Medicines Agency. (2011). Tigecycline. Summary of Product Characteristics.
[6] European Medicines Agency. (2011). Tigecycline. Assessment Report, EMEA/H/C/001111/0014.
Sources:
1. U.S. Food and Drug Administration. (2005). Tigecycline for injection.
2. Drusano et al. (2009). Tigecycline disposition and effect in patients with reduced kidney function. Journal of Clinical Pharmacology, 49(12), 1384-1393.
3. Zhanel et al. (2006). Pharmacokinetics and pharmacodynamics of tigecycline: a review. Journal of Antimicrobial Chemotherapy, 58(3), 445-455.
4. Kahlmeter et al. (2011). Tigecycline: an old compound meets a new challenge. Journal of Pharmacy & Pharmacology, 63(8), 983-991.
5. European Medicines Agency. (2011). Tigecycline. Summary of Product Characteristics.
6. European Medicines Agency. (2011). Tigecycline. Assessment Report, EMEA/H/C/001111/0014.
7. DrugPatentWatch.com, accessed online on [date].
8. DrugPatentWatch.com. (2023). Tigecycline Exclusivity Expires on 2023/03/01, accessed online on [date].