Tolerance and Pharmacokinetics of Galliprant™ Administered Orally to Collies Homozygous for MDR1-1Δ

Comparison of grapiprant and meloxicam for management of postoperative joint pain in dogs: A randomized, double-blinded, prospective clinical trial

BACKGROUND

Grapiprant is a novel anti-inflammatory drug approved for the treatment of pain associated with osteoarthritis in dogs.

OBJECTIVE

Compare the efficacy of grapiprant vs meloxicam for the management of postoperative joint pain in dogs.

ANIMALS

Forty-eight dogs presented with cranial cruciate ligament disease and treated by tibial plateau leveling osteotomy (TPLO) between May 2020 and May 2022.

METHODS

In this randomized, double blinded, prospective clinical trial, client-owned dogs with naturally occurring unilateral cruciate ligament rupture were enrolled on the day of surgery. The day after surgery, all animals received a subcutaneous injection of 0.2 mg/kg of meloxicam and were randomly assigned to receive either oral grapiprant (2 mg/kg) or meloxicam (0.1 mg/kg), once a day for 14 days, in a blinded manner. The primary endpoint of the study was the pain severity (PSS) and interference (PIS) scores, assessed by the Canine Brief Pain Inventory (CBPI) at day 3, 7, 10 and 15 after the surgery.

RESULTS

Three days after surgery, grapiprant treated dogs had lower PSS compared to meloxicam treated dogs with a mean ± SD of 2.76 ± 0.18 vs 3.25 ± 0.23, respectively (difference of -0.49 [95% CI -0.94 to -0.04], P = .032). Pain Interference Score was also lower in grapiprant group at day 3 (4.11 ± 0.18 vs 4.69 ± 0.16 in meloxicam group [difference of -0.58 {95% CI -1.03 to -0.13}, P = .013]) and at day 10 (2.23 ± 0.13 vs 2.72 ± 0.28 [difference of -0.49 {95% CI -0.92 to -0.01}, P = .049]).

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study supports the use of grapiprant as an alternative analgesic to meloxicam for management of postoperative joint pain in dogs.

Canine and feline P-glycoprotein deficiency: What we know and where we need to go

In 2001 the molecular genetic basis of so-called "ivermectin sensitivity" in herding breed dogs was determined to be a P-glycoprotein deficiency caused by a genetic variant of the MDR1 (ABCB1) gene often called "the MDR1 mutation." We have learned a great deal about P-glycoprotein's role in drug disposition since that discovery, namely that P-glycoprotein transports many more drugs than just macrocyclic lactones that P-glycoprotein mediated drug transport is present in more places than just the blood brain barrier, that some cats have a genetic variant of MDR1 that results in P-glycoprotein deficiency, that P-glycoprotein dysfunction can occur as a result of drug-drug interactions in any dog or cat, and that the concept of P-glycoprotein "inhibitors" versus P-glycoprotein substrates is somewhat arbitrary and artificial. This paper will review these discoveries and discuss how they impact drug selection and dosing in dogs and cats with genetically mediated P-glycoprotein deficiency or P-glycoprotein dysfunction resulting from drug-drug interactions.