QuestionSBA
QuestionChoice
Chlortalidone is a thiazide-like diuretic that can be used to treat oedema secondary to heart failure. It inhibits the Na+/Cl- cotransporter at the distal convoluted tubule of nephron, thereby leading to reduced sodium reabsorption and decreased water retention. Chlortalidone is predicted to increase the risk of digoxin toxicity when given with digoxin. (Severity of interaction: Severe; Evidence for interaction: Study). Chlortalidone can lead to hypokalaemia that increases risk of digoxin toxicity. Digoxin normally competes with potassium to bind to cellular Na+/K+-ATPase pumps. Hence, when potassium levels are low, digoxin can more easily bind to the pumps
34300
a
Chlortalidone 50 mg PO OD
QuestionChoice
Carvedilol is not known to interact with digoxin, although it can increase the risk of bradycardia.
34303
d
Rivaroxaban 20 mg PO OD
QuestionChoice
Metformin is not known to interact with digoxin
34302
c
Metformin hydrochloride 500 mg PO TDS
QuestionChoice
Carvedilol is not known to interact with digoxin, although it can increase the risk of bradycardia.
34301
b
Carvedilol 3.125 mg PO BD
QuestionChoice
Lisinopril is not known to interact with digoxin
34304
e
Lisinopril 2.5mg PO OD
QuestionComment
from the BNF: Both Carvedilol and Digoxin can increase the risk of bradycardia.
17515
QuestionComment
Carvedilol increases the risk of bradys as seen here.
Chlortalidone directly interacts to cause digoxin toxicity to cause the ECG changes we are seeing 

So debatably both cause the clinical picture but I think the digoxin toxicity with ECG changes is the major feature in this question
19424
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Gastro X-linked
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Anterior Compartment
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
2803
Digoxin side effects
Topic
74
Elderly Care
Chlortalidone 50 mg PO OD
6871
A 67-year-old woman presents to the accident and emergency department with nausea, vomiting and confusion. Two days ago her GP started digoxin 125 micrograms PO once daily for her atrial fibrillation.
 **PMH:** Type 2 Diabetes Mellitus, Atrial fibrillation, Heart failure
**Observations:** Temperature 36.5°C , blood pressure 125/80 mmHg, heart rate 54 bpm, respiratory rate 18; oxygen saturation 100% (on air).
 
 **On examination:** Irregular S1, S2 with presence of S3; chest is clear with no added lung sounds; abdomen soft and non tender

 **ECG:** Downsloping ST depression with a ‘hockeystick’ pattern, flattened T wave, shortened QT interval
Select the prescription that is most likely to have interacted with digoxin to cause the clinical picture described above?
a