Dosage Guide • FL · NY · VA • Reviewed by Dr. Tiffany Delacruz, DVM
Solensia Dosage for a 18 lb Cat
frunevetmab · Monoclonal antibody (anti-NGF) for feline osteoarthritis · Large adult breed (18 lb / 8.2 kg)
What pet owners in Florida, New York, and Virginia need to know about Solensia dosing for a 18 lb (large Maine Coons-sized) cat — written by a licensed vet, no specific dose given without an exam.
The dosing principle for Solensia
Solensia (frunevetmab) is dosed at a minimum of 1 mg/kg subcutaneously once monthly, administered by a veterinarian. Pre-filled syringes come in fixed volumes (0.4 mL = 5.6 mg, 0.7 mL = 9.8 mg) — vets pick the closest fit for the cat's weight.
Solensia is administered by a veterinarian — there's no at-home component for the injection itself. Weight matters because the dose is fitted to the closest pre-filled syringe size. Most cats respond within 1-2 monthly injections. It's currently considered the most well-tolerated chronic pain option for cats and has revolutionized feline arthritis management.
Why 18 lb matters
A 18 lb (8.2 kg) cat falls into the large adult category — typical examples include large Maine Coons, large Norwegian Forest Cats, and overweight Domestic Shorthairs.
Cats over 15-18 lb are often a mix of genuinely large breed (Maine Coon, Norwegian Forest) and excess body fat. Drug dosing for these cats is calculated based on LEAN body weight — not total weight. Many medications are over-dosed in overweight cats when total weight is used. A vet calculates the lean-mass-adjusted dose during the exam.
What Solensia is approved for
- Chronic pain associated with feline osteoarthritis
What to watch for in your 18 lb cat
- Injection-site reaction (uncommon)
- Vomiting or diarrhea (uncommon)
- Loss of response over time — some cats need dose adjustment or additional therapies
- Most cats tolerate it remarkably well — Solensia is considered the safest chronic pain option for cats
Talk to a RexVet vet in your state
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New York
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Virginia
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Learn more about Solensia
Solensia — Full Drug Guide
Uses, side effects, drug interactions, and how it compares to alternatives.
Frequently asked questions
Frequently asked questions
How much Solensia can I give my 18 lb cat?
Solensia (frunevetmab) is dosed at a minimum of 1 mg/kg subcutaneously once monthly, administered by a veterinarian. Pre-filled syringes come in fixed volumes (0.4 mL = 5.6 mg, 0.7 mL = 9.8 mg) — vets pick the closest fit for the cat's weight. For a 18 lb (8.2 kg) cat, this gives a range that a licensed vet will narrow down based on the indication, your cat's age, kidney/liver function, and any other medications.
Is Solensia safe for a large adult cat like mine?
Solensia (frunevetmab) is widely used in cats in the 18 lb range, but "safe" depends on the specific cat, not just the weight. Cats over 15-18 lb are often a mix of genuinely large breed (Maine Coon, Norwegian Forest) and excess body fat. Drug dosing for these cats is calculated based on LEAN body weight — not total weight. Many medications are over-dosed in overweight cats when total weight is used. A vet calculates the lean-mass-adjusted dose during the exam. A licensed vet will check your cat's history, current medications, and any underlying conditions before prescribing.
What should I watch for after giving my 18 lb cat Solensia?
The most common things to watch for are: Injection-site reaction (uncommon); Vomiting or diarrhea (uncommon); Loss of response over time — some cats need dose adjustment or additional therapies. If you see anything concerning, contact a vet. For large adult cats specifically: Cats over 15-18 lb are often a mix of genuinely large breed (Maine Coon, Norwegian Forest) and excess body fat.
Can a RexVet online vet prescribe Solensia for my 18 lb cat?
Not after a video visit alone. A RexVet veterinarian can discuss whether Solensia is an option; it is given as an injection at a clinic.
Solensia dosing for other cat weights
Sources
Last fact-checked: 2026-06-01. Reviewed by Dr. Tiffany Delacruz, DVM. RexVet (Rex Vets Inc.) is licensed in Florida, New York, and Virginia.
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