Tacalcitol

BRAND NAMES

Curatoderm, Bonalfa- available dosage forms are topical creams, ointments, lotions, and solutions. Apply the ointment at a concentration of 4 micrograms per gram once daily for a duration of up to 8 weeks.

MECHANISM OF ACTION

Tacalcitol, a synthetic vitamin D3 derivative, primarily functions by binding to vitamin D receptors (VDRs) in skin cells to regulate cell growth and immune responses. This mechanism makes it an effective topical treatment for psoriasis and other skin diseases.

PHARMACOKINETICS

Absorption

Tacalcitol, a synthetic vitamin D3 derivative used to treat psoriasis, has minimal absorption through the skin. When applied topically, less than 0.5% of the dose is absorbed through psoriatic skin.

Distribution

Tacalcitol, a synthetic derivative of vitamin D3 used in the treatment of psoriasis, is minimally absorbed through the skin. When applied topically, under 0.5% of the dose is absorbed through psoriatic skin.

Metabolism

Tacalcitol is metabolized into 1-α, 24, 25(OH)₃ vitamin D₃ and subsequently converted into calcitroic acid, an inactive form, with the liver and kidneys involved in this process. Unlike natural vitamin D3, tacalcitol has a diminished impact on systemic calcium metabolism. However, calcium levels should still be monitored in patients with kidney impairment or those at risk for hypercalcemia.

Excretion

Tacalcitol is mainly excreted through the feces, with around 96% of the administered dose eliminated via bile and fecal routes, while less than 4% is excreted in the urine.

PHARMACODYNAMICS

Tacalcitol's pharmacodynamic action involves binding to vitamin D receptors on keratinocytes in the skin, helping to regulate their growth and maturation. This interaction suppresses excessive cell proliferation and encourages proper differentiation, thereby alleviating psoriasis symptoms like scaling. As a synthetic vitamin D3 analog, tacalcitol has a lower risk of causing hypercalcemia compared to some other vitamin D derivatives.

ADMINISTRATION

To use tacalcitol, a vitamin D analogue prescribed for psoriasis and other skin conditions, apply a thin, even layer to the affected areas once or twice daily, ideally before bedtime. Be sure to wash your hands thoroughly after application, unless you are treating your hands.

DOSAGE AND STRENGTH

Tacalcitol is a topical vitamin D3 derivative used to treat psoriasis, available as an ointment or lotion. The typical strength and dosage vary by region, and your specific prescription must be followed. Tacalcitol is commonly formulated at a concentration of 4 micrograms per gram.

DRUG INTERACTIONS

Tacalcitol, a vitamin D analog used for psoriasis, primarily interacts with other drugs and supplements that affect calcium levels, increasing the risk of hypercalcemia. Key interactions include concurrent use with vitamin D supplements, calcium supplements, and thiazide diuretics. It can also be degraded by ultraviolet (UV) light, so patients receiving phototherapy should apply tacalcitol at night. Certain anticonvulsant medications may decrease tacalcitol's effectiveness.

FOOD INTERACTIONS

The risk of food interactions with tacalcitol, a topical vitamin D derivative, is low because absorption through the skin is minimal. Unlike oral medications that are processed by the digestive system, topicals are not significantly affected by food or alcohol. The key interaction to be aware of is with other vitamin D products and supplements, which can increase calcium levels in the blood. 

CONTRAINDICATIONS

Tacalcitol is contraindicated in individuals with hypersensitivity to the drug or in patients with conditions that affect calcium levels. As a synthetic vitamin D3 derivative, tacalcitol can affect calcium metabolism, so it may not be safe for individuals with existing calcium imbalances.

SIDE EFFECTS

• Itching.

• Skin redness or irritation.

• Burning or stinging sensation.

• Tingling sensation.

• Contact dermatitis.

• burning sensation at the application site. 

• tingling.

OVER DOSE

Symptoms of severe overdose may include: 

• Nausea and vomiting.

• Loss of appetite.

• Unusual tiredness and muscle weakness.

• Stomach or abdominal pain.

• Constipation.

• Headache.

• Dry mouth.

• Increased urination.

• Altered mental status, such as confusion or depression.

• In rare, severe cases, acute pancreatitis, lethargy, or coma.

TOXICITY

Tacalcitol toxicity is rare with topical application, but it may cause hypercalcemia, a potentially serious condition characterized by increased calcium levels in the blood. Possible symptoms include fatigue, nausea, vomiting, bone discomfort, and kidney-related problems.