Asthma

Question 1

Tell me about salbutamol?

Answer 1

B2 agonist used for asthma, COPD, hyperkalaemia and prevention of pre-term labour

Physical:
CCS, inhaled and oral

PK:
Big first pass and large Vd
Hepatic metabolism and renal excretion

PD: primarily B2 but some B1
B: dilate and inhibits HPV (can worsen shunt so always give meds with O2)
C: tachy and hypo
D: anxiety

Other: decreased uterine tone, stimulates na/K pump moving K in, increased BM

Question 2

Tell me about aminophylline?

Answer 2

Methylxanthine derivative used for same as salbutamol

Physical:
Tabs, supps and CCS

PK:
High oral
Small Vd
Zero order at higher doses. Tachy, tremor, seizures and rhabdo.

Pd:
Moa: stimulates B2
B: dilation, increased diaphragmatic contractility and O2 sensitivity centrally
C: increased HR and CO, but decreased SVR
D: decreased seizure
E: SIADH
F: weak diuretic

Question 3

What are the physiological effects of steroids?

Answer 3

Increased glucose, mobilisation of amino acids to make sugar, stimulation of lipolysis

Increased cortisol increasing effect of catecholamines

Needed for foetal development and cognitive function