QuestionMultiA
QuestionChoice
33867
f
Salmeterol;50 micrograms;Inhaled (INH);12-hourly
QuestionChoice
33862
a
Amlodipine;5mg;Oral (PO);Daily
QuestionChoice
33863
b
Perindopril erbumine;8 mg;Oral (PO);Daily
QuestionChoice
33864
c
Bendroflumethiazide;2.5 mg;Oral (PO);Daily
QuestionChoice
33866
e
Simvastatin;40mg;Oral (PO);Daily
QuestionChoice
33869
h
Bisoprolol;5 mg;Oral (PO);OD
QuestionChoice
33865
d
Omeprazole;20mg;Oral (PO);Daily
QuestionChoice
33868
g
Theophylline (Uniphyllin Continus®);200mg;Oral (PO);12-hourly
QuestionComment
Budesonide also causes hypokalaemia
6819
User
subscriber
Neoplasia Sclerosis
QuestionComment
Hypomagnesaemia (caused by omeprazole) can also precipitate hypokalaemia 
38249
User
subscriber
Supine Metabolism
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
2722
Myopathy & drugs causing hypokalemia
Topic
9
Internal Medicine
1. Bendroflumethiazide is a thiazide-like diuretic. It inhibits the Na+/Cl- cotransporter at the distal convoluted tubule of nephron, leading to reduced Na+ reabsorption. As a result of the reduced reabsorption, the concentration of Na+ left in the urine increases. The increase in Na+ availability increases the activity of Na+/K+-ATPase in the collecting duct and brings about an increase in excretion of K+ into the urine. Salmeterol is a long-acting β2 adrenergic receptor agonist (LABA). β2 adrenergic receptor agonist decreases the serum K+ level via an inward shift of K+ into the cells. Theophylline is a phosphodiesterase inhibitor. It is also known to cause hypokalaemia. BNF highlights that concomitant treatment of β2 adrenergic receptor agonist with theophylline may potentiate potentially serious hypokalaemia.
2. Myalgia is a common or very common side effect of simvastatin.
6789
c f g
e
Case presentation: A 49-year old man presents to the emergency walk-in clinic with muscle weakness and constipation. He also complains that he has been having pain in the muscles of his upper arms. PH: Hypertension, Asthma, GORD, Hypercholesterolaemia DH: Her current regular prescriptions are listed below




 **On examination**: Chest is clear with no added lung sounds. Heart sounds I + II + 0. Abdomen soft and non tender.


 **Vital signs**: BP 125/80, Temperature 36.5°C, HR 80, O2 Sat 99% (room air), RR 18


 **Investigations**:


 - ECG: Prolonged QT, mild ST depression, presence of U wave


||||
|--------------|:-------:|---------------|
|Haemoglobin|130   g/L|(M) 130 - 170, (F) 115 - 155|
|White Cell Count|5x10<sup>9</sup>/L|3.0 - 10.0|
|Platelets|320x10<sup>9</sup>/L|150 - 400|
|Mean Cell Volume (MCV)|95 fL|80 - 96|
|Neutrophils|5x10<sup>9</sup>/L|2.0 - 7.5|
|Lymphocytes|2x10<sup>9</sup>/L|1.5 - 4.0|
|Sodium|140 mmol/L|135 - 145|
|Potassium|3 mmol/L|3.5 - 5.3|
|Urea|7 mmol/L|2.5 - 7.8|
|Creatinine|109 µmol/L|60 - 120|


Question 1: Select the THREE prescriptions that are most likely to be a cause of his hypokalaemia (mark them with a tick in column A)
Question 2: Select the ONE prescription that should be withheld in view of the patient’s myopathy? (mark it with a tick in column B)