Posterior pituitary hormones and antagonists

Question 1

Which is more potent and has a longer duration of action: Vasopressin or Desmopressin?

Answer 1

Desmopressin

Question 2

Does vasopressin or desmopressin have vasoconstrictor effects?

Answer 2

Vasopressin

Question 3

Following a dose of IM or intranasal desmopressin, restoration of the ability to concentrate urine after water deprivation confirms a diagnosis of (?) diabetes insipidus

Answer 3

cranial

Failure to respond occurs in nephrogenic diabetes insipidus

Question 4

Which diuretic may provide benefit in nephrogenic and partial pituitary diabetes insipidus?

Answer 4

Thiazides

In nephrogenic and partial pituitary diabetes insipidus benefit may be gained from the paradoxical antidiuretic effect of thiazides.

It is thought the initial diuresis it causes prompts a hypovolaemia that results in increased sodium and water reabsorption.

Question 5

Which anti-epileptic drug is sometimes useful in partial pituitary diabetes insipidus [unlicensed]

Answer 5

Carbamazepine

It may act by sensitising the renal tubules to the action of remaining endogenous vasopressin

Question 6

(?) is also used to boost factor VIII concentration in mild to moderate haemophilia and in von Willebrand’s disease

Answer 6

Desmopressin

Question 7

Desmopressin is also used to boost (?) concentration in mild to moderate haemophilia and in von Willebrand’s disease

Answer 7

factor VIII

Question 8

Desmopressin is also used to boost factor VIII concentration in mild to moderate (1?) and in (2?) disease

Answer 8

1. haemophilia

2. von Willebrand’s disease

Question 9

Terlipressin acetate is a derivative of (?)

Answer 9

vasopressin

Question 10

What two hormones are produced from the posterior pituitary?

Answer 10

Vasopressin

Oxytocin

Question 11

Which of the folllowing drugs is used in nocturnal enuresis: Vasopressin or Desmopressin?

Answer 11

Desmopressin

Question 12

Which of the following drugs is used to control variceal bleeding in portal hypertension (prior to definitive treatment): Vasopressin or Desmopressin?

Answer 12

Vasopressin

Question 13

Which of the following drugs is used to test fibrinolytic response: Vasopressin or Desmopressin?

Answer 13

Desmopressin

Question 14

What are the contra-indications to the use of desmopressin?

Answer 14

1. Cardiac insufficiency
2. Conditions treated with diuretics
3. Hyponatraemia
4. Polydipsia in alcohol dependence
5. Psychogenc polydipsia
6. SIADH
7. von Willebrand’s disease type IIB

Question 15

Desmopressin can be used to boost factor VIII concentration in von Willebrand’s disease, however, which type of von Willebrand’s disease is a contraindication for the use of desmopressin?

Answer 15

Type IIB

May result in pseudothrombocytopenia

Question 16

Why is caution required when prescribing desmopressin in elderly patients?

Answer 16

Increased risk of hyponatraemia and renal impairment

Question 17

What are the common side effects of desmopressin?

Answer 17

Hyponatraemia

Nausea

Question 18

Why should you avoid concomitant use of desmopressin and a tricyclic antidepressant?

Answer 18

Increases risk of hyponatraemia

Tricyclic antidepressants increase secretion of vasopressin

Question 19

Desmopressin and vasopressin has a small (?) effect in this trimester of pregnancy

Answer 19

oxytocic

Question 20

If desmopressin is taken during pregnancy there is an increased risk of (?)

Answer 20

pre-eclampsia

Question 21

What needs to be monitored if desmopressin is used in nocturia?

Answer 21

BP
Weight checks

Monitor for fluid overload

Question 22

What are the two indications for the use of vasopressin?

Answer 22

Pituitary diabetes insipidus

Initial control of oesophageal variceal bleeding

Question 23

What are the contra-indications to the use of vasopressin?

Answer 23

Chronic nephritis
Vascular disease (especially of coronary arteries)

Question 24

Which drug is used in the treatment of hyponatraemia resulting from inappropriate secretion of antidiuretic hormone?

Answer 24

Demeclocycline hydrochloride

Used if fluid restriction alone does not restore sodium concentration

Question 25

What class of drug is demeclocycline hydrochloride?

Answer 25

Tetracycline

Question 26

Demeclocycline hydrochloride is thought treat hyponatraemia by directly blocking the (?) effect of antidiuretic hormone

Answer 26

renal tubular

Question 27

What class of drug is tolvaptan?

Answer 27

Vasopressin V2-receptor antagonist

Licensed for the treatment of hyponatraemia secondary to SIADH

Question 28

Rapid correction of hyponatraemia during tolvaptan therapy can cause (?) leading to serious neurological events

Answer 28

Osmotic demyelination