Sildenafil

Question 1

absorption

Answer 1

absolute bioavailability of 40% and rapidly absorbed

Question 2

distribution

Answer 2

distributed into tissues and 96% bound to plasma proteins

Question 3

metabolism

Answer 3

extensively and rapidly metabolised by liver by CYP3A4 enzyme

Question 4

excretion

Answer 4

excreted in faeces and urine

Question 5

MOA

Answer 5

1. Phosphodiesterase type V inhibitor
2. works by increasing the quantity of cyclic guanosine monophosphate
3. enhances effect of nitric oxide

Question 6

indications

Answer 6

1. pulmonary arterial hypertension
2. digital ulcers

Question 7

adverse effects

Answer 7

• anaemia
• fluid retention
• increased risk of infection

Question 8

interactions

Answer 8

• methadone
• salbutamol

Question 9

contraindications

Answer 9

• recent history of MI
• sickle cell anaemia