CaliciX™ Max 30 mg | Severe feline calicivirus (FCV) capsules

1. Active ingredient

EIDD-1931 (β-D-N4-hydroxycytidine) 30 mg per capsule Active metabolite of molnupiravir (EIDD-2801) Mutagenic nucleoside analogue acting on RNA-dependent RNA polymerase (RdRp) Pharmacologically equivalent to approximately 133 mg of molnupiravir

2. Therapeutic class

• Direct-acting antiviral (DAA)

• Broad-spectrum RNA virus inhibitor

• Viral error catastrophe inducer

3. Mechanism of action

EIDD-1931 is phosphorylated intracellularly to its triphosphate form and incorporated into viral RNA during replication. Transition mutations accumulate, viral genome integrity is lost, and production of infectious virus is suppressed. The mechanism is host-independent and does not act through viral proteases, which is thought to limit the development of resistance.

4. Indications

Severe or refractory disease associated with feline calicivirus.

Severe oral disease

• Severe feline chronic gingivostomatitis (FCGS)

• Caudal stomatitis with extensive inflammation

• Ulcerative stomatitis unresponsive to extraction

• Viral glossitis with deep lingual ulceration

• Multifocal buccal, labial and palatal ulcers

Virulent systemic feline calicivirus

• Virulent systemic feline calicivirus (VS-FCV)

• Fever and lethargy

• Facial and limb oedema

• Lameness

• Pneumonia and respiratory deterioration

• Inflammatory changes in the liver and pancreas

Refractory and high-risk cases

• Feline chronic gingivostomatitis remaining active after extraction

• Continued calicivirus shedding

• Cases relapsing after steroid or immunosuppressant use

• Larger cats requiring greater antiviral exposure

5. Clinical signs addressed

Intense oral pain, drooling, difficulty swallowing and food refusal, oral bleeding and ulceration, halitosis, weight loss and wasting, fever and systemic inflammation.

6. Dosage and administration

• Route: oral

• Frequency: twice daily, every 12 hours

• High-dose range: above 6 mg/kg, under veterinary direction

7. Pharmacokinetics

• Good oral bioavailability

• Rapid systemic absorption

• Intracellular activation independent of host enzymes

• Distribution into oral mucosa, salivary tissue and sites of inflammation

• Stable exposure without dependence on prodrug conversion

Formal feline pharmacokinetic studies are ongoing. Dosing rests on translational data and clinical experience.

8. Safety

Contraindications

• Pregnant queens and cats intended for breeding

• Cats with a history of hypersensitivity to nucleoside analogues

Use with caution

• Cats with hepatic impairment

• Cats with renal disease, particularly alongside NSAIDs

• Long-term use beyond 12 weeks without monitoring

Monitoring

• CBC every 2 to 4 weeks on prolonged courses

• ALT/AST where other systemic medication is in use

• Weight and appetite records

Possible adverse effects

• Mild gastrointestinal upset

• Transient lethargy

• Dose-dependent effects on long courses

9. Interactions

No major CYP-mediated interactions are known. Can be combined with analgesics as directed by your veterinarian, NSAIDs under renal monitoring, antibiotics for secondary infection, and dental care.

10. Regulatory status

This product is not licensed for use in cats. It is intended for off-label veterinary use under professional supervision and requires informed owner consent.

11. Storage

Store below 25 °C, protected from moisture and light, in the original packaging until use.

Dosage

• Under 2.5 kg: 1 capsule every 12 hours

• 2.5 to 5 kg: 2 capsules every 12 hours

• Over 5 kg: 3 capsules every 12 hours

Size 3 capsules, small and easy to give whole or with the contents mixed into food.

If the cat vomits within 30 minutes of dosing, repeat the same dose.

Choosing between CaliciX™ and CaliciX™ Max

Mild to moderate disease uses CaliciX™ 15 mg: early ulceration, juvenile gingivitis, gingivostomatitis with difficulty eating and drooling, moderate ulceration.

Severe disease uses CaliciX™ Max 30 mg: feline chronic gingivostomatitis, caudal stomatitis, extensive ulceration, marked pain, complete food refusal.

Duration

• Moderate: 6 to 8 weeks

• Severe feline chronic gingivostomatitis: 8 to 12 weeks or longer

Beyond 12 weeks, continue with monitoring in place.

Signs the dose is insufficient

• Persistent drooling

• Pain on chewing

• Slow ulcer resolution

• Continued weight loss

Any increase stays within the recommended range and under veterinary direction.

Storage

Store below 25 °C, away from moisture and direct sunlight.

Packaging

60 capsules in a vacuum-sealed pouch.

Shelf life

12 months from the manufacturing date shown on the pack.

CaliciX™ Max can usually be combined with other treatments. Note the following.

Can be combined with

• Antibiotics (amoxicillin, clindamycin, azithromycin)

• Analgesics (gabapentin)

• Appetite stimulants (mirtazapine, maropitant)

• Vitamin B12

• Probiotics

• Most chronic disease medication including thyroid and blood pressure

Use with caution under veterinary supervision

• NSAIDs (meloxicam, robenacoxib): monitor renal function closely

• Steroids (prednisolone, dexamethasone): short-term overlap is acceptable, taper as CaliciX™ Max takes effect

• Chemotherapy agents: additive myelosuppression possible

• Immunosuppressants (ciclosporin): may blunt the immune response needed to clear the virus

Avoid

• Ribavirin and other antivirals: overlapping mechanisms increase toxicity risk

• Experimental antivirals without veterinary direction

Tell us every medication your cat is receiving when you get in touch.

To uphold the highest standards of pharmaceutical safety, quality, and product integrity, we are unable to accept returns or issue refunds once an order has been delivered. This ensures that every product that reaches our customers has been handled, stored, and managed according to strict quality control requirements.

If your order is damaged, defective, or lost in transit, we will provide a free replacement at no additional cost to you. Simply contact our support team with your order details, and we will resolve the issue promptly.

This policy protects the safety of all customers and ensures that every product dispensed remains uncompromised and fully compliant with pharmaceutical standards.

EIDD-1931 (active ingredient, antiviral) 30 mg Dibasic calcium phosphate (excipient)