VETINUITY
Lomustine is dosed at 60-90 mg/m2 PO every 3 weeks in dogs and 50-60 mg/m2 PO every 3 to 6 weeks in cats, rounded to whole capsules, with ALT and a CBC checked before every dose.
Round the result down to the nearest whole capsule; capsules are never opened.
Per the Vetinuity lomustine dose calculator above, dogs receive lomustine (CCNU) at 60 to 90 mg/m2 PO once every 3 weeks, most often 70 mg/m2 when it is paired with a liver protectant, and cats receive 50 to 60 mg/m2 PO every 3 to 6 weeks; both doses are rounded down to whole capsules. Vetinuity, the clinical assistant built by emergency veterinarian Brian Toncray, DVM, keeps this table with its sources for the moment the dose has to be checked.
| Indication | Dog | Cat | Route and interval |
|---|---|---|---|
| Lymphoma rescue | 70 to 90 mg/m2 | 50 to 60 mg/m2 | PO every 3 weeks (dog), 3 to 6 weeks (cat) |
| Mast cell tumor | 60 to 70 mg/m2 | 50 to 60 mg/m2 | PO every 3 weeks |
| Histiocytic sarcoma | 60 to 90 mg/m2 | not established | PO every 3 weeks |
| Brain tumors (palliative) | 60 to 80 mg/m2 | not established | PO every 6 weeks in some reports |
The resistant-lymphoma series that set the dog rescue dose used 90 mg/m2 every 3 weeks (Moore 1999). A practical feline regimen of one 10 mg capsule per cat every 3 weeks was assessed in 20 tumor-bearing cats (Fan 2002).
Commercial capsules come in 10, 40 and 100 mg strengths, and compounding pharmacies make smaller ones. Work out the mg/m2 dose, then round down to the nearest combination of whole capsules; never open a capsule. A 20 kg dog has a body surface area near 0.74 m2, so 70 mg/m2 is about 52 mg, given as one 40 mg and one 10 mg capsule. Owners wear gloves to handle capsules and pick up feces and vomit for 48 hours.
For where lomustine sits after CHOP, read lymphoma rescue protocols; for other single agents, read carboplatin.
After CHOP relapse, options are re-induction with CHOP, lomustine 70-90 mg/m2 every 3 weeks, LPP, DMAC every 2 weeks, or rabacfosadine 1 mg/kg IV every 3 weeks.
CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) is first-line for canine nodal lymphoma: median survival 302 to 321 days; prednisone alone 50 days.
Carboplatin is given at 300 mg/m2 IV every 3 weeks in dogs and 200-240 mg/m2 IV every 3 to 4 weeks in cats, with the dose reduced for poor kidney function.
COP gives cyclophosphamide 300 mg/m2 PO every 3 weeks, vincristine 0.75 mg/m2 IV weekly for 4 weeks then every 3 weeks, and daily prednisolone, in dogs and cats with lymphoma.
In a randomized trial, dogs given Denamarin (S-adenosylmethionine and silybin) alongside lomustine had smaller ALT increases and fewer treatment delays from hepatotoxicity than dogs given placebo (Skorupski 2011).
No. Lomustine is a carcinogen and the capsule contents should not be handled. Use a compounding pharmacy for doses below the smallest commercial capsule.
In dogs the neutrophil nadir comes about a week after a dose. Cats show a later, more cumulative drop, with thrombocytopenia that can build over several cycles (Rassnick 2001).
Vetinuity explains clinical options with journal citations.
The veterinarian diagnoses and prescribes.