Users of hair-loss treatments are being warned about the hidden dangers of the medication on pet cats following more than 20 reported cases of poisoning.

Minoxidil is widely used as an over-the-counter treatment for thinning hair and, while safe for humans, cats are extremely sensitive to it, with potentially devastating effects.

The Veterinary Poisons Information Service recorded 20 feline poisonings last year, though the true number is likely higher as reporting is not mandatory. 

Head of Cat Welfare Engagement at Cats Protection Sarah Merrett said: “The potential side effects of these treatments on cats are not widely appreciated so we are keen to get the message out urging caution around these therapies if you are a cat owner.

“Direct ingestion from bottles or applicators is uncommon. Most poisonings occur through everyday, unintended contact with owners. Cats may lick freshly applied minoxidil from skin, ingest residue transferred to fur during grooming, or encounter traces left on bedding or clothing. In documented cases, even very small amounts, such as drops or accidental spills onto a cat’s coat, have caused life-threatening illness.”

Minoxidil can induce profound hypotension in cats, with reported effects including pulmonary oedema or pleural effusion, respiratory distress, weakness and collapse. Many symptomatic cats described in published cases required intensive care, and some deteriorated rapidly. 

Fortunately, risks can be greatly reduced through simple precautions, says Sarah.

“Topical products should be applied away from pets, hands washed thoroughly afterwards and treatments allowed to dry fully before contact with animals. Cats should be kept away from bedding that may have been contaminated and all medications kept securely out of reach. Anyone unsure about the safety of a product should seek advice and, if an owner suspects their cat has licked or touched any human topical medication, they should immediately contact their vet.”

Minoxidil is not the only concern however, says the charity. Cats groom themselves frequently, so any product that remains on human skin can potentially be ingested. This includes anti-inflammatory gels (such as ibuprofen), Hormone Replacement Therapy gels, and other dermal medications that are highly toxic to cats. Also of concern are psoriasis creams or ointments containing potent forms of vitamin D, and anticancer treatments such as 5-fluorouracil (eg Efudix), all of which can be lethal even in minute quantities. 

“Given the frequency with which GPs prescribe or recommend dermal treatments, a brief reminder to patients with pets could help prevent avoidable and distressing toxicities,” says Sarah.

Further information is available at: Keeping Your Cat Safe in the Home | Cats Protection