Drug interactions- summary

Decreased absorption with neomycin.

Increased risk of hypervitaminosis A with synthetic retinoids eg acitretin ,
isotretininin and tretinon

Increased risk of toxicity when used with alcohol

Vitamin A deficiency

Hypervitaminosis A  characterised by fatigue , irritability , anorexia, weight loss,
vomiting

Other GI disturbances , low grade fever, hepatosplenomegaly,

skin changes, alopecia, dry hair, cracking and bleeding lips,

SC swelling, noctiria, pains in bone and joints

Hypervitaminosis A

Pregnancy, doses exceeding RDA

Special precautions-

Cholestatic jaundice, fat-malabsorption conditions.

Monitor patients closely for toxicity

Liver impairment and children

Indications-

Vitamin A deficiency

Dosage-
Adults- for severe deficiency-  with corneal changes-
500,000u daily for 3 days followed by 50.000u daily for 3 days for 2 weeks and then
10.000u -20,000u  daily for 2 months as follow up therapy

For corneal changes 10.000u -25000 u daily until clinical improvement occurs
(usually 1-2 weeks )

Child- with xerophthalmia  - 5000 units /kg daily for 5 days or until recovery occurs

Intramuscular -
Patients with biliary cirrhosis or chronic chloestatic liver disease-
adult- 100,000u every 2-4 months

Observe caution