QuestionSBA
QuestionChoice
If a patient has forgotten to take a dose the day before, the patient is advised to skip the missed dose and take the normal dose at usual time. Patient is reminded to not take more than 1 dose a day
34078
d
If he has forgotten to take a dose of warfarin the day before, he should take 2 doses today to make up
QuestionChoice
Warfarin can interact with many other drugs because it is metabolised by cytochromes P450 enzymes. CP450 inhibitors such as erythromycin can potentiate the anti-coagulatory effect and make bleeding more likely
34077
c
Warfarin can be safely taken along with antibiotics such as erythromycin and co-trimoxazole
QuestionChoice
Warfarin is a Vitamin K antagonist that promotes anticoagulation. Food that contains a lot of vitamin K, for example green leafy vegetables and liver, can interfere with how warfarin works. Hence, patients are advised to keep a stable diet and consult their doctors before changing to a completely new diet
34075
a
He should keep his diet stable and speak to his doctor before changing to a completely new diet
QuestionChoice
With regards to blood test monitoring, patients only require a blood test once every 6 to 8 weeks if the INR levels have become stable
34079
e
Once the international normalised ratio (INR) is within the therapeutic range, he still requires lifelong blood test on a weekly basis to ensure that the INR remains stable
QuestionChoice
Warfarin is a Vitamin K antagonist that promotes anticoagulation
34076
b
Warfarin decreases blood clotting by working against Vitamin A
Concept
Chapter
#### Monitoring

The BNF advises to monitor lung function (in patients with a history of obstructive airway disease).

#### Overdoses

Overdosages with beta-blockers may cause cardiac effects such as bradycardia, hypotension, syncope, conduction abnormalities, and heart failure. Bradycardia is the most common arrhythmia, but some beta-blockers may induce ventricular tachyarrhythmias secondary to prolongation of QT interval (e.g. sotalol) or QRS duration (e.g. propranolol).
Non-cardiovascular effects include central nervous system effects (including drowsiness, confusion, convulsions, hallucinations, and in severe cases coma), respiratory depression, and bronchospasm.

Management
 - Airway protection 
 - Activated charcoal within 1 hour
 - IV Fluids
 
IV glucagon is the first-line management.
 
For symptomatic bradycardia, IV atropine may be used.

2618
2759
Warfarin interactions
Topic
9
Internal Medicine
6826
Case presentation: A 65-year-old man presents to the emergency department with sudden-onset shortness of breath. He also complains of stabbing chest pain during inhalation and exhalation.  

PMH: Prostate cancer, Hypertension, Diabetes Mellitus
DH: Enalapril maleate 20mg PO OD, Metformin Hydrochloride 500mg TDS
Investigation: Computed tomographic pulmonary angiography confirms the diagnosis of pulmonary embolus.
Treatment with 80mg Enoxaparin subcutaneous injection twice daily was initiated. Treatment with warfarin is to be commenced after 5 days.

Question: Select the most important information that should be provided for this patient.
a