Hydroxychloroquine

Question 1

What is HCQ?

Answer 1

An anti-malarial used as a anti-inflammatory in inflammatory conditions

Mechanism of action for this purpose is not well understood

Question 2

What is the dose of HCQ?

Answer 2

200mg - 400mg a day

Max dose is 5mg / kg

Question 3

What are the side effects of HCQ?

Answer 3

CHONG

C- cutaneous
H - haematology
O - ocular
N - neuropathy and neuromuscular
G - GIT

Ocular
- corneal deposits
—> mainly an issue for chloroquine rather than HCQ

• retinopathy
  —> occurs at daily dose > 5 mg/ kg
  —> occurs after duration of use > 5 years

Gastrointestinal side effects:
- flatulence
- vomiting
- diarrhoea

Cutaneous side effects
- pigmentation: grey - blue, 25% of patients on long term therapy
- urticaria
- lichenoid eruptions
- alopecia
- photosensitivity
- EAC
- achromotrichia
- itch
- exac. psoriasis

Neuropysch side effects (very rare)
- psychosis
- irritability
- depression
- insomnia
- nightmares
- seizures
- Tinnitus / vertigo

Neuromuscular
- proximal myopathy

Haemolysis
- in g6pd deficiency (rare - screening is not routine)

Question 4

Pregnancy classification of HCQ?

Answer 4

Category D

However
- used in neonatal lupus
- no evidence of congenital defects / still birth, prematurity, low birth weight, etc

Question 5

Common uses of HCQ in Derm?

Answer 5

Lupus
PCT

Dermatomyositis
PMLE
Sarcoidosis

Question 6

HCQ -
Pre-treatment investigations

Answer 6

Baseline eye check
FBC, UEC, LFTS, CMP

Question 7

HCQ
- monitoring Ix

Answer 7

Monthly FBC, UEC, LFTS for 3 months
Then 4-6 monthly
Eye checks annually after 5 years

Question 8

What are the cutaneous AE of HCQ?

Answer 8

Blue grey hyperpigmentation
- sun exposed areas

Hypersensitivity reaction
- lichenoid
- eczematoua
- urticaria
- SJS / TEN

Psoriasis (induced or exacerbated)

Transverse pigment bands on nails

Question 9

List the names and doses of the different antimalarial agents

Answer 9

Hydroxychloroquine
- 200 - 400 mg OD

Chloroquine
- 250 - 500 mg OD

Quinacrine
- 100 - 200 mg OD

Question 10

Antimalarials
- Absorption?
- Distribution?
- Metabolism?
- Excretition?

Answer 10

Absorption: very good, quick oral absorption

Distribution: bind to tissue proteins, resulting in higher tissue than plasma concentateion and long half life

Metabolised in the liver

Excreted in the urine

Question 11

Contraindications of antimalarials

Answer 11

Hypersensitivity

Relative:
- Blood dyscrasias
- Known retinal / ocular issues
- Neurological issues

Question 12

What interaction can HCQ have?

Answer 12

Prolong QtC