Paricalcitol (chemically it is 19-nor-1,25-(OH)2-vitamin D2. Marketed by Abbott Laboratories under the trade name Zemplar) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic kidney failure. It is an analog of 1,25-dihydroxyergocalciferol, the active form of vitamin D2 (ergocalciferol). It was patented in 1989 and approved for medical use in 1998. Medical uses
Its primary use in medicine is in the treatment of secondary hyperparathyroidism associated with chronic kidney disease. However current evidence is not sufficient to demonstrate an advantage of paricalcitol over non-selective vitamin D derivatives for this indication. Adverse effects
Adverse effects by frequency:Very common (>10% frequency):

NauseaCommon (1-10% frequency):

Uncommon (0.1-1% frequency):

‡ These are adverse effects only seen in patients with grade 3 or 4 chronic kidney disease. † These are adverse effects only seen in patients with grade 5 chronic kidney disease. Contraindications
Contraindications include:
Vitamin D intoxication
Hypercalcaemia
Hypersensitivity to paricalcitol or any of its excipientswhereas cautions include:
Impaired liver function
It is also advised that physicians regularly monitor their patients calcium and phosphorus levels. Interactions
Drugs that may interact with paricalcitol include:

Overdose
Electrolyte abnormalities (e.g. hypercalcaemia and hyperphosphataemia) are common overdose symptoms. Treatment is mostly supportive, with particular attention being paid to correcting electrolyte anomalies and reducing intake of calcium in both the form of supplementation and diet.
Special consideration must be taken in individuals with opioid dependency as naloxone administration can induce severe opioid withdrawal, hence the recommended starting doses above. Goal of naloxone therapy is to restore respiratory drive in the individual, however mechanical ventilation may still be necessary during initial resuscitation. Bag-valve-mask (BVM) ventilation devices
Resistance to bag valve mask may suggest presence of a foreign body that is obstructing airways and commonly used as a diagnostic tool and treatment for respiratory arrest. The bag-valve-mask device has a self-inflating bag with a soft mask that rests on the face. When the bag is connected to an oxygen supply, the patient will receive 60 to 100% of inspired oxygen. The purpose of bag-valve-mask is to provide adequate temporary ventilation and allow the body to achieve airway control by itself. However, if the bag-valve-mask is left on for more than five minutes, air may be introduced into the stomach. At that point, a nasogastric tube should be inserted to take the accumulated air out. During this process, practitioners must carefully position and maneuver the bag-valve-mask in order to keep airways open. To ensure an adequate seal when using the bag valve mask to ventilate, specific hand positioning is typically used. The provider places his or her thumb and index finger in a C shape on top of the mask and grips the jaw under the mask with the other three fingers, creating an E shape.