Prescribing Flashcards
What is the dose of a drug in a solution that is 0.1%
0.1% = 0.1g per 100ml
- Name an absolute contraindication to gentamycin therapy
2. name 4 relative contraindications to gentamycin therapy
- myasthenia gravis
- creatinine clearance <50ml/min
pregnancy/breastfeeding
ascites/limb amputation
burns
Describe the following methods of gentamycin administration:
- once daily dosing
- multiple daily dosing
- 5-7mg/kg/day; levels monitored 6-14 hours after start of drug administration; dose interval adjusted according to serum gentamycin levels based on Hartford Normogram
- 3-5mg/kg/day in divided doses given 8 hourly; interval adjusted according to peak and trough levels of serum gentamycin. LESS COMMONLY USED
When prescribing gentamycin, what weight is used to calculate dose?
How does this differ in underweight patients?
What is the max dose regardless of weight?
Ideal body weight for patient’s height
7mg/kg of actual body weight, rounded to nearest 40
560mg
Name 2 DOACs contraindicated in patients with poor renal function
dabigatran
Rivaroxiban
Anticoagulation and Surgery When should the following be stopped prior to surgery: 1. Warfarin 2. DOACs 3. Antiplatelet Agents 4. Aspirin
- 3-5 days before; aim to achieve INR of <1/5
- 48 hours before
- 5 days before
- continue unless high bleeding risk during surgery (neurosurgery, prostatectomy)
You want to start a patient on Warfarin. What must be considered during initiation of this?
Bridging anticoagulation with LMWH
A patient on anticoagulation has obtained a head injury. Within what time frame should they have a CT head?
Name 6 reasons in which this CT head must be performed sooner, and within what time frame?
- 8hours
- perform within 1 hour if:
- Initial GCS <13
- GCS <15 after 2 hours
- suspected skull/basal skull #
- seizure
- focal neurological deficit
- 1+ episode of vomiting
- How regularly does warfarin therapy need to be monitored initially?
- How long does warfarin therapy need to be monitored once stable?
- daily/alternate days
2. every 12 weeks
Describe the fast induction method of warfarin therapy
- bridge with LMWH until INR is at target for 2 consecutive days
- dose given is dependent on INR that day.
- Dose is recalculated daily depending on INR
- Target INR given as a range ± 0.5
How is warfarin reversal achieved in a patient presenting with MAJOR BLEEDING
- stop warfarin
- give 5mg phytomenadione (vitamin K)
- give prothrombin complex concentrate
What should be done for a patient presenting with minor bleeding, who is on warfarin therapy and their INR >8
- stop warfarin
- give 1-3mg of vitamin K
- Repeat dose of vitamin K if INR still too high after 24 hours
- Restart warfarin when INR < 5.0
What should be done for a patient whose INR >8, but they are not bleeding
Stop warfarin
Give vitamin K 1-5mg by mouth, using the intravenous preparation orally
Repeat dose of vitamin K if INR still too high after 24 hours
Restart when INR < 5.0
A patient presents with minor bleeding. They take warfarin and their INR falls within the range of 5-8. What should be done?
Stop warfarin
Give intravenous vitamin K 1-3mg
Restart when INR < 5.0
A patient has an INR within the range of 5-8. They are not bleeding. What should be done?
Withhold 1 or 2 doses of warfarin
Reduce subsequent maintenance dose
