Friday, September 30, 2011
SYNDROMES
Wyburn–Mason syndrome: This congenital, nonhereditary disorder stems from a developmental abnormality of the vascular mesoderm in the optic cup and neural tube. This constellation of ipsilateral–intraorbital and cerebral arteriovenous malformations, which is often associated with facial nevi,
Wednesday, September 28, 2011
Pradaxa
Dabigatran (Pradaxa in Australia, Europe and USA, Pradax in Canada, Prazaxa in Japan) is an anticoagulant from the class of the direct thrombin inhibitors. It is being studied for various clinical indications and in some cases it offers an alternative to warfarin as the preferred orally administered anticoagulant ("blood thinner") since it does not require frequent blood tests for international normalized ratio (INR) monitoring while offering similar results in terms of efficacy
fondaparinaux
One potential advantage of fondaparinux over LMWH or unfractionated heparin is that the risk for heparin-induced thrombocytopenia (HIT) is substantially lower. Furthermore, there have been case reports of fondaparinux being used to anticoagulate patients with established HIT as it has no affinity to PF-4. However, its renal excretion precludes its use in patients with renal dysfunction.
Unlike direct factor Xa inhibitors, it mediates its effects indirectly through antithrombin III, but unlike heparin, it is selective for factor Xa.[1]
Heparin
An IV heparin protocol
When intravenous UFH is initiated for DVT anticoagulation, the goal is to achieve and maintain an elevated activated partial thromboplastin time (aPTT) of at least 1.5 times control. Heparin pharmacokinetics are complex, and the half-life is 60-90 minutes. A protocol for IV heparin use is as follows:
- Give an initial bolus of 80 U/kg.
- Initiate a constant maintenance infusion of 18 U/kg.
- Check the aPTT or heparin activity level 6 hours after the bolus, and adjust the infusion rate accordingly.
- Continue to check the aPTT or heparin activity level every 6 hours, until 2 successive values are therapeutic.
- Monitor the aPTT or heparin activity level, hematocrit, and platelet count every 24 hours.