Can Chromatography Help Cats with Hypertension?

Who knew that cats can get stressed? But apparently, they can suffer from stress just like us humans — this is hypertension, a form of psychological stress but more commonly associated with very high blood pressure.

A recent study has investigated the treatment of cats with hypertension who were treated similarly to humans who attend hospital with hypertension. The study was published in the Journal of Veterinary Internal Medicine and aimed to see whether individual cat factors affected how cats responded to treatment with amlodipine — a standard treatment for humans and cats with hypertension.

Poor old kitty

Hypertension is a common occurrence in older cats — particularly cats who suffer from chronic kidney disease. The reason why cats get high blood pressure is not really understood. If it is untreated it can lead to organ damage — particularly those organs with a rich blood supply like the eye, kidney or brain.

The published study set out to discover whether individual factors like age, weight and systolic blood pressure influence the amount of medicine a cat needs to return its blood pressure to normal and to see if there are other factors that might affect the amount of amlodipine in the cat’s blood.

Amlodipine is used in the treatment of humans, as well as other animals, with hypertension. Officially, it is a calcium channel blocker — but effectively it works by dilating, or widening, the blood vessels which leads to improved blood flow and reduced pressure.

Felinology — the study of cats

In the study, 100 cats — over nine years old — who had previously been treated for systemic hypertension were studied. Systemic hypertension was defined as having a systolic blood pressure (SBP) of over 170 mm Hg at two consecutive checks. The cats renal function was also checked to check the health of their kidneys.

The cats were given a dose of amlodipine once a day and the SBP was rechecked one or two weeks later. The target SBP was <160 mm Hg — cats which had higher had additional doses of amlodipine. Once the blood pressure had reduced, blood samples were taken to check the cat’s renal function.

Bigger doses for more stressed cats

Animals having a greater initial SBP needed more amlodipine to stabilise their blood pressure — a similar regime is needed in humans with hypertension. But higher doses meant proportionally higher blood concentrations of amlodipine — suggesting that an individual cat’s factors don’t affect the medicine. The blood plasma levels were determined by liquid chromatography with tandem mass spectrometry. The use of LC-MS/MS for drugs analysis is discussed in the article, A Simplified Mixed-Mode Sample Preparation Strategy for the LC-MS/MS Analysis of Benzodiazepines and Z-Drugs for Forensic Toxicology.

Stroking cats has been suggested as a method of reducing stress in humans — wonder if it works in reverse?