Mast-cell stabilisers, Antihistamines and Mucolytics

Question 1

List 4 sedating Antihistamines

Answer 1

1) Chlorphenamine
2) Promethazine
3) Hydroxyzine
4) Alimemazine

Question 2

Which condition should antihistamines be avoided in?

Answer 2

Avoid sedating antihistamines in severe liver disease as they may precipitate hepatic encephalopathy

Question 3

How should loratadine be dosed in renal impairment ?

Answer 3

Reduce dose frequency to alternative days

Question 4

What are the age restrictions on chlorphenamine tablets and syrup?

Answer 4

1) Tablets- not for under 6 years

2) Syrup- not licensed for under 1 year old

Question 5

1) Outline the MHRA alert regarding the use of hydroxyzine HCL
2) Which patients are most at risk adverse effect?

Answer 5

1) Associated with a small risk of QT-interval prolongation and torsade de pointes (specific type of arrhythmia that can lead to sudden death)
2) Concomitant use of drugs that prolong QT-interval, CV disease, family history of sudden cardiac death, significant electrolyte imbalance or significant bradycardia

Question 6

How can the risk of of QT-interval prolongation and torsade de pointes be reduced in those using hydroxyzine? (4)

Answer 6

1) C/I in patients with prolonged QT-interval or who have risk factors for QT prolongation
2) Consider the risks before prescribing to patients taking drugs that lower heart rate or plasma-potassium
3) In children with body-weight up to 40 kg, the maximum daily dose is 2 mg/kg
4) Prescribe lowest effective dose for shortest period

Question 7

Due to the safety concerns regarding the use of desensitising vaccines such as Bee venom/grass pollen extracts, which conditions should they only be used in? (2)

Answer 7

1) Seasonal allergic hay fever that has not responded to anti-allergic drugs
2) Hypersensitivity to wasp and bee venoms
↳ (avoid/use with care in asthma)

Question 8

1) List two mucolytic drugs

2) What condition are mucolytic drugs contraindicated in?

Answer 8

1) Acetylcysteine and Carbocysteine

2) Peptic ulceration

Question 9

List two mast-cell stabilisers used in asthma

Answer 9

1) Nedocromil

2) Sodium cromoglicate

Question 10

Which drug is more effective for the prophylaxis of asthma; ICS or mast cell stabilisers?

Answer 10

Prophylaxis with ICS is more effective than prophylaxis with mast-cell stabilisers (sodium cromoglicate)

Question 11

Can mast-cell stabilisers be used for acute asthma attacks?

Answer 11

No - they are used for prophylaxis

Sodium cromoglicate can prevent exercise-induced asthma

Question 12

What are mast-cell stabilises (sodium cromoglicate) used for?

Answer 12

Prophylaxis of exercise-induced asthma