Vitamin A

What is vitamin A?

Vitamin A is an essential nutrient used to supplement animals with vitamin A deficiency. It is used in all species to prevent or treat low vitamin A levels. It may be used off label in dogs to treat certain skin conditions, such as sebaceous adenitis, vitamin A-responsive dermatosis, and primary seborrhea.

Vitamin A for injection is available in combination with the other fat-soluble vitamins (vitamin D and/or E) and is labeled for use in newborn or adult cattle, sheep, and swine. Human-labeled products are used off label (extra label) in pets and livestock.

Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How do I give my pet vitamin A?

• Vitamin A is given orally, topically, and by injection.
• Apply topical preparations as directed by your veterinarian. Wear gloves when applying topical preparations.
• Give injections into the muscle (IM) or under the skin (SQ). Do not inject into the vein (IV), as anaphylactic shock and death have occurred in humans after IV injection.
• When given orally (by mouth), formats include drops, capsules/softgels, tablets, and oral solutions.
• Follow your veterinarian’s directions and measure liquid forms of this medication carefully.
• This medication should be given with food; ideally, food with a high fat content.
• Do not use more than one form of vitamin A at the same time as another, to avoid toxic levels of vitamin A in the body (hypervitaminosis A).
• Do not handle this drug if you are pregnant, as excess vitamin A can cause physical defects or abnormalities in a developing fetus or embryo.

This medication should take effect within 24 hours; however, improvement in clinical signs may take up to 4–8 weeks.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects from vitamin A?

Vitamin A may cause the following side effects:

• Gastrointestinal signs, such as vomiting and/or diarrhea
• Skin irritation and itchiness
• Behavioral changes
• Local pain at the injection site (when injected form is used)

Serious adverse reactions may occur, particularly in cats. If any of the following signs develop, stop giving vitamin A and contact your veterinarian immediately:

• Red eyes, thick mucoid discharge, squinting
• Changes of the skin and coat, such as poor coat quality, hair loss, and firm, raised bumps
• Excessive bleeding
• Changes to the liver (seen on bloodwork)

All injectable medications have the potential to cause an immediate allergic or anaphylactic reaction which can be severe and life-threatening. If any of the following signs develop after injection, stop giving vitamin A and contact your veterinarian immediately:

• Swelling
• Hives
• Changes in respiration
• Signs of agitation

Drug sensitivities can develop over time, with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of the treatment and notify your veterinarian if you have any concerns. Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

DO NOT USE in:

• Pets that are sensitive to it
• Pets with existing high levels of vitamin A (hypervitaminosis A)
• Pets that are pregnant

USE WITH CAUTION in:

• Cats (may be more susceptible to developing high levels of vitamin A, leading to side effects)

Are there any drug interactions I should be aware of?

The following drugs should be used with EXTREME CAUTION when given with vitamin A:

• Chlortetracycline
• Doxycycline
• Isotretinoin
• Oxytetracycline
• Tetracycline
• Warfarin

The following drugs should be used with CAUTION when given with vitamin A:

• Cholestyramine
• Clopidogrel
• Heparin
• Mineral Oil
• Minocycline
• Neomycin
• Nitrofurantoin
• Pentosan polysulfate sodium

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this medication?

• At home, monitor for any side effects such as those noted above. If any side effects occur, discontinue the medication and contact your veterinarian.
• Patients using this medication long-term should have liver enzymes checked before starting treatment, and then every 6 to 12 months.
• A Schirmer tear test (STT) is recommended for pets using vitamin A long-term, at an interval recommended by your veterinarian.
• Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.

How do I store vitamin A?

• Ensure oral vitamin A is stored in a tightly sealed container and secured inside a cabinet to prevent accidental ingestion.
• Store this medication in a cool, dry place and protected from light.
• Store the injection between 36°F and 46°F (2°C and 8°C). Do not freeze.
• Keep the container out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet’s weight and symptoms.