See the DrugPatentWatch profile for tigecycline

Tigecycline is a antibiotic used to treat various bacterial infections, including complicated skin and intra-abdominal infections. The volume of distribution (Vd) of a drug is a pharmacokinetic parameter that describes the distribution of the drug in the body after administration. It is the volume into which the total amount of drug in the body would need to be uniformly distributed to produce the observed concentration.

The Vd of tigecycline is approximately 500-900 Liters, which is large compared to other antibiotics. This indicates that tigecycline distributes widely throughout the body, including to tissues and fluids such as the lungs, bones, and urine. This wide distribution is beneficial in treating infections in various body sites.

The large Vd of tigecycline affects dosing in several ways. First, it results in a long half-life of approximately 27 hours, which allows for once- or twice-daily dosing. This is convenient for patients and can improve compliance. However, it also means that tigecycline has a slow clearance rate, which can lead to drug accumulation and increased risk of adverse effects in patients with impaired renal or hepatic function.

Second, the large Vd of tigecycline affects the loading dose required to achieve therapeutic concentrations quickly. A larger loading dose is needed to account for the wide distribution of the drug. The recommended loading dose of tigecycline is 100 mg, followed by 50 mg every 12 hours.

In conclusion, the large volume of distribution of tigecycline affects dosing by requiring a larger loading dose and resulting in a long half-life and slow clearance rate. These factors must be considered when prescribing tigecycline to ensure appropriate dosing and minimize the risk of adverse effects.

Sources:

1. [Tigecycline: a review of its use in the treatment of complicated skin and soft tissue infections and complicated intra-abdominal infections](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4364335/)
2. [Pharmacokinetics and Pharmacodynamics of Tigecycline](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3784233/)
3. [Tigecycline: a first-in-class glycylcycline antibiotic for the treatment of serious infections due to multidrug-resistant bacteria](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689754/)
4. [Tigecycline - DrugPatentWatch.com](https://www.drugpatentwatch.com/drugs/tigecycline)