Vitamin A (Retinol, Isotretinoin, Tretinoin)

Vitamin A (Retinol, Isotretinoin, Tretinoin) In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Nutritional fat-soluble hormone that regulates gene expression.
• Tretinoin (all-trans retinoic acid) is the acid form of vitamin A and isotretinoin (13-cis retinoic acid) is an isomer of tretinoin.

Uses of Vitamin A (Retinol, Isotretinoin, Tretinoin)

• Treatment of hypovitaminosis A.
• Also used in conjunction with other appropriate therapies for sebaceous adenitis or primary seborrhoea of Cocker Spaniels.

Dose of Vitamin A (Retinol, Isotretinoin, Tretinoin) in Dogs and Cats

Dogs:

• Hypovitaminosis A: 10,000–100,000 IU/dog i.m. q3d, no more than 2 doses; 10,000 IU/dog p.o. q24h for 3 days.
• Dermatological lesions: 10,000 IU/dog p.o. q24h or apply isotretinoin/tretinoin gel/cream to clean skin q12h; 1 mg isotretinoin/kg p.o. q12h for 1 month, reducing the dosage to 1 mg/kg p.o. q24h if improvement is seen.

Cats:

• Hypovitaminosis A: 10,000–100,000 IU/cat i.m. q3d, no more than 2 doses; 10,000 IU/cat p.o. q24h for 3 days.

Side Effects of Vitamin A (Retinol, Isotretinoin, Tretinoin) in Dogs and Cats

• Oral isotretinoin use in humans is associated with various adverse effects, primarily affecting the skin, haematological parameters, liver function, nervous system, and bone structure.
• Dogs and cats receiving high doses of isotretinoin also experience similar abnormalities.
• Isotretinoin is teratogenic when administered during the first trimester of pregnancy or at high doses.
• Skin redness and pigmentation may occur after several days of isotretinoin use.
• It alters tear lipid content, potentially causing keratoconjunctivitis sicca (dry eye).
• Isotretinoin may induce hyperlipidemia and hepatotoxicity at high doses.
• Prolonged vitamin A use, including isotretinoin, can lead to calcium loss from bones and result in hypercalcemia.
• Do not use isotretinoin topical preparations simultaneously with other topical medications.

Contraindications of Vitamin A (Retinol, Isotretinoin, Tretinoin) in Dogs and Cats

• Do not use it in pregnant animals.

Some Notes:

• Animals receiving oral dosing of vitamin A should be monitored for signs of vitamin A toxicity.
• Avoid simultaneous use of oral and topical vitamin A preparations due to the risk of toxicity.
• Refrain from using formulations of vitamins A, D3, and E authorized for farm animals or horses, as they are too concentrated for small animal use.
• Oral vitamin A may affect ciclosporin levels, necessitating close monitoring of ciclosporin levels.