Oral Hypercalcaemia associated with parathyroid carcinoma or primary hyperparathyroidism
Adult: Initially, 30 mg bid, titrated through sequential doses of 30 mg bid, 60 mg bid, 90 mg bid, and 90 mg 3-4 times daily as necessary 2-4 wkly to normalise serum Ca levels. Max: 90 mg 4 times daily.
Oral Secondary hyperparathyroisim in patients with chronic kidney disease on dialysis
Adult: Initially, 30 mg once daily, titrated in increments of 30 mg 2-4 wkly to achieve intact parathyroid hormone (iPTH) levels of 150-300 pg/mL. Max: 180 mg once daily.
Chống chỉ định
Serum Ca below the lower limit of normal range.
Patient w/ history of seizure disorders, known congenital long QT syndrome, impaired cardiac function. Smokers. Not indicated for use in CKD patients not on dialysis. Moderate to severe hepatic impairment. Pregnancy and lactation.
Monitor for signs and symptoms of hypocalcaemia. Secondary hyperparathyroidism: Monitor serum Ca and phosphorus levels prior to and w/in a wk of initiation, and regularly during dose titrations. Obtain serum Ca levels mthly after establishing maintenance dose. Measure iPTH 1-4 wk after initiation or dose titrations (wait at least 12 hr after dose). Hypercalcaemia: Monitor serum Ca levels prior to and w/in a wk of initiation or dose titrations. Obtain serum Ca levels 2 mthly after establishing maintenance dose.
Symptoms: Hypocalcaemia manifested by paraesthesia, myalgia, cramping, tetany, and seizures. Management: Symptomatic and supportive treatment.
Increased concentration by 2-fold w/ strong CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, telithromycin, ritonavir). May increase exposure of desipramine, amitriptyline, and nortriptyline. May increase AUC of dextromethorphan.
Increased peak plasma concentration and bioavailability w/ food.
Description: Cinacalcet is a calcimimetic agent that increases the sensitivity of the Ca-sensing receptors of the parathyroid gland to activation by extracellular Ca. This lowers parathyroid hormone (PTH) levels, and leads to concomitant decrease in serum Ca and phosphorus levels, thereby preventing complications w/ mineral metabolism disorders. Pharmacokinetics: Absorption: Increased bioavailability w/ food. Time to peak plasma concentration: Approx 2-6 hr. Distribution: Volume of distribution: Approx 1,000 L. Plasma protein binding: Approx 93-97%. Metabolism: Rapidly and extensively metabolised by CYP3A4, CYP2D6, and CYP1A2 enzymes via oxidative N-dealkylation to hydrocinnamic acid and hydroxy-hydrocinnamic acid (further metabolised via β-oxidation and glycine conjugation) and metabolites containing naphthalene ring; also via oxidation of the naphthalene ring on the parent drug to form dihydrodiols which are further conjugated w/ glucuronic acid. Excretion: Via urine (approx 80%, as metabolites) and faeces (approx 15%). Terminal elimination half-life: Approx 30-40 hr.
H05BX01 - cinacalcet ; Belongs to the class of other anti-parathyroid agents. Used in the management of calcium homeostasis.
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