Veterinary drug · Drug monograph

Calcitriol: veterinary dose and monograph

Calcitriol is a veterinary drug. Active vitamin D used in NANOGRAMS per kg: to control renal secondary hyperparathyroidism in CKD (only once phosphorus is controlled) and for hypoparathyroidism/post-thyroidectomy hypocalcaemia. Indications include renal secondary hyperparathyroidism (CKD); hypoparathyroidism / hypocalcaemia (e.g. after thyroidectomy); idiopathic seborrhoea (spaniels). This monograph lists 5 reference doses for dogs and cats, each with route, frequency and source.

At a glance

Drug class: Veterinary drug
Also known as: 1,25-dihydroxycholecalciferol, Rocaltrol, Active vitamin D3
Species with doses: Dogs and Cats
Routes: PO
Last reviewed: 1 October 2026

Indications

Renal secondary hyperparathyroidism (CKD)
Hypoparathyroidism / hypocalcaemia (e.g. after thyroidectomy)
Idiopathic seborrhoea (spaniels)

Calcitriol dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

Calcitriol doses for dogs
Indication	Dose	Route	Frequency	Duration
Renal secondary hyperparathyroidism (CKD)	2.5–3.5 ng/kg PO q24h	PO	q24h (empty stomach, at bedtime)	—
Hypoparathyroidism / chronic hypocalcaemia	5–30 ng/kg/day PO (divided q12h)	PO	20–30 ng/kg/day for 3–4 days, then 5–15 ng/kg/day, divided q12h	—
Idiopathic seborrhoea (spaniels)	10 ng/kg PO q24h	PO	q24h, away from meals	—

Renal secondary hyperparathyroidism (CKD): Papich 5e: 2.5 ng/kg PO once daily, increasing to 3.5 then up to 5 ng/kg by PTH and calcium; alternative 10 ng/kg twice weekly. Plumb’s p.181: 2.5–3.5 ng/kg/day; refractory cases up to 6–6.6 ng/kg/day with ionised-calcium monitoring; pulse dosing about 20 ng/kg twice weekly (Nagode; Chew). Check calcium on days 7 and 14, then every 6 months; PTH at 4–6 weeks.
Hypoparathyroidism / chronic hypocalcaemia: Plumb’s p.181: initially 20–30 ng/kg/day divided twice daily for 3–4 days, then 5–15 ng/kg/day (Chew & Nagode); long-term 30–60 ng/kg/day with oral calcium, adjusted to serum calcium (Crystal).
Idiopathic seborrhoea (spaniels): Plumb’s p.181 (Kwochka 1999).

Cats

Calcitriol doses for cats
Indication	Dose	Route	Frequency	Duration
Renal secondary hyperparathyroidism (CKD)	1.5–5 ng/kg PO q24h	PO	q24h, apart from meals	—
Hypocalcaemia after parathyroid/thyroid surgery	10–40 ng/kg/day PO	PO	q24h (or 0.25 µg per cat q48h)	—

Renal secondary hyperparathyroidism (CKD): Papich 5e: 2.5 ng/kg once daily, increasing to 3.5 and up to 5 ng/kg/day — do not exceed 5 ng/kg/day; alternative 10 ng/kg twice weekly. Plumb’s p.181: 1.5–3.5 ng/kg daily (Gunn-Moore); 2.5–3.5 ng/kg (Chew).
Hypocalcaemia after parathyroid/thyroid surgery: Papich 5e: 0.25 µg per cat q48h, or 10–40 ng/kg/day PO. Plumb’s p.181 (Crystal): long-term 30–60 ng/kg/day with oral calcium, adjusted to serum calcium.

Contraindications

Hypercalcaemia; uncontrolled hyperphosphataemia (reduce phosphorus below ~6 mg/dL first); vitamin D toxicosis. Avoid calcium-containing phosphate binders with calcitriol (hypercalcaemia).

Adverse effects

Hypercalcaemia (reversible fall in GFR if prolonged)
Hyperphosphataemia

Monitoring

Serum calcium (ionised if possible) on days 7 and 14, then regularly
Phosphorus and creatinine every 1–3 months
PTH 4–6 weeks after starting (CKD)

Formulations and products

0.25 µg capsule
0.5 µg capsule
Oral solution 1 µg/mL

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Frequently asked questions

What is the dose of Calcitriol for dogs?

Reference doses for Calcitriol in dogs: 2.5–3.5 ng/kg PO q24h PO q24h (empty stomach, at bedtime) (Renal secondary hyperparathyroidism (CKD)); 5–30 ng/kg/day PO (divided q12h) PO 20–30 ng/kg/day for 3–4 days, then 5–15 ng/kg/day, divided q12h (Hypoparathyroidism / chronic hypocalcaemia); 10 ng/kg PO q24h PO q24h, away from meals (Idiopathic seborrhoea (spaniels)). Confirm against the label and the patient before use.

What is the dose of Calcitriol for cats?

Reference doses for Calcitriol in cats: 1.5–5 ng/kg PO q24h PO q24h, apart from meals (Renal secondary hyperparathyroidism (CKD)); 10–40 ng/kg/day PO PO q24h (or 0.25 µg per cat q48h) (Hypocalcaemia after parathyroid/thyroid surgery). Confirm against the label and the patient before use.

When should Calcitriol not be used?