Kris­tel-Marie Ram­nath

When pets are in pain, own­ers of­ten make the as­sump­tion that med­ica­tions they use to re­lieve pain in them­selves will be safe to use in their pets. The prob­lem is that every species is dif­fer­ent, and what is safe for hu­mans can be lethal to a dog or a cat.

Non-steroidal an­ti-in­flam­ma­to­ry drugs (NSAIDs) are com­mon over-the-counter and pre­scrip­tion med­ica­tions used to re­lieve pain and re­duce in­flam­ma­tion (swelling) in hu­mans. NSAID tox­i­c­i­ty in cats can oc­cur when a cat ac­ci­den­tal­ly gains ac­cess to the prod­uct (med­ica­tion bot­tle, pills, or creams) or when the pet par­ent in­ten­tion­al­ly gives an over-the-counter hu­man NSAID prod­uct to their cat to al­le­vi­ate pain with­out re­al­is­ing the dan­ger these drugs pose. The most com­mon­ly in­gest­ed NSAIDs in pets are over-the-counter hu­man med­ica­tions, specif­i­cal­ly ibupro­fen (Advil, Motrin), as­pirin (Bay­er), and naprox­en (Aleve).

NSAIDs work by in­hibit­ing an en­zyme called cy­clooxy­ge­nase (COX). This en­zyme is in­volved in the pro­duc­tion of in­flam­ma­to­ry com­pounds called prostaglandins. Cells use the COX en­zyme to be­gin to con­vert fats from their cell mem­branes in­to prostaglandins, which con­tribute to in­flam­ma­tion and pain. By block­ing COX, NSAIDs re­duce the pro­duc­tion of prostaglandins, there­by de­creas­ing the in­flam­ma­tion and pain that they would cause.

How­ev­er, there are sev­er­al types of cy­clooxy­ge­nase, and while some are in­volved in pro­duc­ing in­flam­ma­to­ry prostaglandins, oth­ers are in­volved in pro­duc­ing prostaglandins need­ed for nor­mal body func­tions, such as main­tain­ing blood sup­ply to the stom­ach and kid­neys. Some com­mon NSAIDs, such as Ibupro­fen, are non-se­lec­tive cy­clooxy­ge­nase in­hibitors, which means that they in­hib­it all types of cy­clooxy­ge­nase, not just the ones that pro­duce the in­flam­ma­to­ry prostaglandins.

In hu­mans, the ef­fects of NSAIDs de­creas­ing prostaglandins to the stom­ach and kid­neys are mi­nor enough that these drugs are still ap­proved for hu­man use, but in cats these is­sues are life-threat­en­ing.

Ini­tial symp­toms of NSAID tox­i­c­i­ty in cats usu­al­ly de­vel­op with­in 2 – 6 hours af­ter in­ges­tion, and in­clude vom­it­ing, nau­sea (drool­ing), di­ar­rhoea, loss of ap­petite, lethar­gy, loss of bal­ance, in­crease in drink­ing and uri­na­tion, and seizures. The main ar­eas of con­cern are stom­ach ul­cer­a­tion (which can re­sult in bleed­ing in­to the gas­troin­testi­nal tract re­sult­ing in bloody vom­it or di­ar­rhoea), kid­ney fail­ure, and brain dam­age (in high dos­es).

There are no safe over-the-counter hu­man pain med­ica­tions for cats. On­ly two NSAIDs are FDA-ap­proved for cats: meloxi­cam (sold un­der sev­er­al brand and gener­ic names) and robe­na­cox­ib (sold un­der the brand name ON­SIOR).

Meloxi­cam is ap­proved for cats as a one-time-on­ly in­jec­tion to con­trol pain and in­flam­ma­tion af­ter spay­ing, neu­ter­ing, and or­thopaedic surgery. The in­jec­tion is giv­en un­der the cat’s skin be­fore surgery. Robe­na­cox­ib is al­so ap­proved for cats to con­trol pain and in­flam­ma­tion af­ter spay­ing, neu­ter­ing, and or­thopaedic surgery. The med­ica­tion should be used once dai­ly for no more than three days and is avail­able as ei­ther a tablet giv­en by mouth or an in­jec­tion giv­en un­der the cat’s skin.

Cur­rent­ly, no NSAIDs are ap­proved for long-term use in cats. More than one dose (re­peat­ed dos­es) of meloxi­cam in cats can cause kid­ney fail­ure or death, and more than three dos­es of robe­na­cox­ib have not been shown to be safe in cats.

If your cat has in­gest­ed an NSAID, you should take him im­me­di­ate­ly to your vet­eri­nar­i­an. It is very im­por­tant to bring the prod­uct, in­clud­ing la­bel in­for­ma­tion with spe­cif­ic drug name and mil­ligram of med­ica­tion, an es­ti­ma­tion of amount in­gest­ed (num­ber of tablets), and when the in­ges­tion oc­curred.

Parac­eta­mol is one of the most com­mon over-the-counter painkillers, and while it not con­sid­ered a true NSAID, it is ex­treme­ly tox­ic to cats. Cats can­not break down parac­eta­mol and tox­ins are pro­duced that se­ri­ous­ly dam­age their liv­er and red blood cells. Even part of a sin­gle tablet can cause se­vere tox­i­c­i­ty and death.

Al­ways keep med­ica­tions in a safe and se­cure place away from pets.

Copy­right © Kris­tel-Marie Ram­nath 2023