My current advice based on the published evidence is that patients
on 200-400mg daily should have baseline retinal screening and that
thereafter eye screening is not necessary until the patient has been
on therapy for five years. This advice however conflicts with other guidelines.

http://www.rcophth.ac.uk/docs/publications/published-guidelines/
Oculartoxicity2004.pdf

GUIDELINE FOR THE PRESCRIPTION AND MONITORING OF
HYDROXYCHLOROQUINE FOR THE RHEUMATIC DISEASES
Henry Averns

This shared care guideline sets out details for the sharing of care
of patients with rheumatoid arthritis prescribed
hydroxychloroquine These guidelines provide additional limited
information necessary to aid in the treatment of rheumatology
patients. As with all shared care guidelines these highlight
significant prescribing issues but should be used in conjunction
with the summary of product characteristics (Data sheet) and do
not replace the companies information .

INTRODUCTION/BACKGROUND INFORMATION

INDICATION FOR THE PURPOSES OF THIS GUIDELINE
Treatment of rheumatoid arthritis and connective tissue diseases

DOSAGE
The dose is 200mg once to twice daily; adjusted to lean body
weight. On line calculators will help you calculate lean body weight. Does 0.6mg per kg lean weight.

Long half life (up to 40 days in adults) means that steady
state may take several months to achieve

CONTRAINDICATIONS
o Contraindicated in patients with pre-existing maculopathy.

o Caution in patients with liver or renal disease, severe gastro-
intestinal, neurological and blood disorders.

o Caution in G6PD deficiency or quinine sensitivity

PRECAUTIONS:
o Toxic in overdose, particularly in children. Parenteral diazepam
has been shown to reverse chloroquine cardiotoxicity.

o May precipitate attacks of psoriasis




ONGOING MONITORING -
Routine blood monitoring is not required.


SIDE EFFECTS

o Gastro-intestinal disturbance -
Nausea, diarrhoea, anorexia, abdominal cramps.

o Visual disturbance -see above

o Skin rashes
Pigmentary changes, bleaching of hair and hair loss, are both rare
and usually resolve on stopping the drug.

o Rare reports of bone-marrow suppression


PREGANANCY AND BREAST FEEDING
Hydroxychloroquine crosses the placenta. In the doses used in
treatment of rheumatological conditions there is probably an
increased risk as a chemically related compound chloroquine
phosphate has been found to cause chochlear damage.
Breast feeding is not recommended due to risk of accumulation in
the infant.


DRUG INTERACTIONS

o Digoxin levels may be increased

o Antacids may reduce absorption of hydroxychloroquine

o Ciclosporine levels may be increased

Date of Issue March 2008; Reviewed 10/09