Get your patient on Gavilyte G  tm - Polyethylene Glycol-3350 And Electrolytes powder, For Solution (Polyethylene Glycol-3350 And Electrolytes)

GaviLyte-G is indicated for bowel cleansing prior to colonoscopy and barium enema X-ray examination in adults.

GaviLyte-G, supplied as a powder, must be reconstituted with water before its use; it is not for direct ingestion [see Dosage and Administration (2.2) , Warnings and Precautions (5.8) ]. The 4 liter reconstituted GaviLyte-G solution contains: 236 grams of polyethylene glycol (PEG) 3350, 22.74 grams sodium sulfate (anhydrous), 6.74 grams of sodium bicarbonate, 5.86 grams of sodium chloride, and 2.97 grams of potassium chloride. GaviLyte-G is supplied with lemon flavor pack.

On the day prior to the colonoscopy, instruct patients to:

1. Take only clear liquids, but avoid red and purple liquids. Patients may consume a light breakfast.
2. Early in the evening prior to colonoscopy , fill the supplied container containing the GaviLyte-G powder with lukewarm water (to facilitate dissolution) to the 4 liter fill line. The solution is clear and colorless when reconstituted to a final volume of 4 liters.
3. After capping the container, shake vigorously several times to ensure that the ingredients are dissolved. When reconstituted use within 48 hours.

The following is the recommended dose of reconstituted GaviLyte-G solution for adults. Instruct patients they may consume water or clear liquids during the bowel preparation and after completion of the bowel preparation up until 2 hours before the time of the colonoscopy. The solution is more palatable if chilled prior to administration.

• Adults: Instruct patients to drink a total of 4 liters at a rate of 240 mL (8 oz.) every 10 minutes, until 4 liters are consumed or the rectal effluent is clear. Rapid drinking of each portion is preferred to drinking small amounts continuously. For NGT, rate is 20-30 mL per minute (1.2 – 1.8 liters per hour).

The first bowel movements should occur approximately one hour after the start of GaviLyte-G administration.  Continue drinking until the watery stool is clear and free of solid matter.

For oral solution: One 4 liter jug with powder for reconstitution with water.

Each 4 liter jug contains: polyethylene glycol 3350 236 g, sodium sulfate (anhydrous) 22.74 g, sodium bicarbonate 6.74 g, sodium chloride 5.86 g, potassium chloride 2.97 g. When made up to 4 liters volume with water, the solution contains PEG-3350 17.6 mmol/L, sodium 125 mmol/L, sulfate 40 mmol/L, chloride 35 mmol/L, bicarbonate 20 mmol/L and potassium 10 mmol/L.

Pregnancy Category C.

Animal reproduction studies have not been conducted with GaviLyte-G. It is also not known whether GaviLyte-G can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. GaviLyte-G should be given to a pregnant woman only if clearly needed.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when GaviLyte-G is administered to a nursing woman.

Safety and effectiveness of GaviLyte-G in pediatric patients have not been established.

Clinical studies of GaviLyte-G did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

GaviLyte-G is contraindicated in the following conditions:

• Gastrointestinal (GI) obstruction, ileus, or gastric retention
• Bowel perforation
• Toxic colitis or toxic megacolon
• Known allergy or hypersensitivity to any component of GaviLyte-G [ see How Supplied/Storage and Handling (16) ]

Advise patients to hydrate adequately before, during, and after the use of GaviLyte-G. Use caution in patients with congestive heart failure when replacing fluids. If a patient develops significant vomiting or signs of dehydration including signs of orthostatic hypotension after taking GaviLyte-G, consider performing post-colonoscopy lab tests (electrolytes, creatinine, and BUN) and treat accordingly. Fluid and electrolyte disturbances can lead to serious adverse events including cardiac arrhythmias, seizures and renal impairment. Fluid and electrolyte abnormalities should be corrected before treatment with GaviLyte-G.

In addition, use caution when prescribing GaviLyte-G for patients who have conditions, or who are using medications, that increase the risk for fluid and electrolyte disturbances or may increase the risk of adverse events of seizure, arrhythmias, and renal impairment [ see Drug Interactions (7.1) ]

There have been rare reports of serious arrhythmias associated with the use of ionic osmotic laxative products for bowel preparation. Use caution when prescribing GaviLyte-G for patients at increased risk of arrhythmias (e.g., patients with a history of prolonged QT, uncontrolled arrhythmias, recent myocardial infarction, unstable angina, congestive heart failure, or cardiomyopathy).  Pre-dose and post-colonoscopy ECGs should be considered in patients at increased risk of serious cardiac arrhythmias.

There have been reports of generalized tonic-clonic seizures and/or loss of consciousness associated with use of bowel preparation products in patients with no prior history of seizures. The seizure cases were associated with electrolyte abnormalities (e.g., hyponatremia, hypokalemia, hypocalcemia, and hypomagnesemia) and low serum osmolality. The neurologic abnormalities resolved with correction of fluid and electrolyte abnormalities.

Use caution when prescribing GaviLyte-G for patients with a history of seizures and in patients at increased risk of seizure, such as patients taking medications that lower the seizure threshold (e.g., tricyclic antidepressants), patients withdrawing from alcohol or benzodiazepines, or patients with known or suspected hyponatremia.

Use caution when prescribing GaviLyte-G for patients with impaired renal function or patients taking concomitant medications that may affect renal function (such as diuretics, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or non-steroidal anti-inflammatory drugs).  Advise these patients of the importance of adequate hydration, and consider performing baseline and post-colonoscopy laboratory tests (electrolytes, creatinine, and BUN) in these patients.

Administration of osmotic laxative products may produce colonic mucosal aphthous ulcerations, and there have been reports of more serious cases of ischemic colitis requiring hospitalization. Concurrent use of stimulant laxatives and GaviLyte-G may increase this risk. The potential for mucosal ulcerations resulting from the bowel preparation should be considered when interpreting colonoscopy findings in patients with known or suspect inflammatory bowel disease (IBD).

If gastrointestinal obstruction or perforation is suspected, perform appropriate diagnostic studies to rule out these conditions before administering GaviLyte-G. If a patient experiences severe bloating, distention or abdominal pain, administration should be slowed or temporarily discontinued until the symptoms abate. If gastrointestinal obstruction or perforation is suspected, appropriate studies should be performed to rule out these conditions before administration of GaviLyte-G.

Use with caution in patients with severe active ulcerative colitis.

Use with caution in patients with impaired gag reflex, unconscious, or semiconscious patients, and patients prone to regurgitation or aspiration. Such patients should be observed during administration of PEG-3350 and electrolytes for oral solution, especially if it administered via nasogastric tube.

The contents of each jug must be diluted with water to a final volume of 4 liters (4L) and ingestion of additional water is important to patient tolerance. Direct ingestion of the undissolved powder may increase the risk of nausea, vomiting, dehydration, and electrolyte disturbances.

The following adverse reactions have been identified during post-approval use of GaviLyte-G. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Nausea, abdominal fullness and bloating are the most common adverse reactions (occurred in up to 50% of patients) to administration of GaviLyte-G. Abdominal cramps, vomiting and anal irritation occur less frequently. These adverse reactions are transient and usually subside rapidly. Isolated cases of urticaria, rhinorrhea, dermatitis and (rarely) anaphylactic reaction have been reported which may represent allergic reactions.

Published literature contains isolated reports of serious adverse reactions following the administration of PEG-electrolyte solution products in patients over 60 years of age. These adverse events include upper GI bleeding from Mallory-Weiss Tear, esophageal perforation, asystole, sudden dyspnea with pulmonary edema, and "butterfly-like" infiltrates on chest X-ray after vomiting and aspirating PEG.

Use caution when prescribing GaviLyte-G for patients who are using medications that increase the risk for fluid and electrolyte disturbances or may increase the risk of adverse events of seizure, arrhythmias, and prolonged QT in the setting of fluid and electrolyte abnormalities. Consider additional patient evaluations as appropriate [ see Warnings and Precautions (5.1 , 5.2 , 5.3 , and 5.4 ) ] in patients taking these concomitant medications.

Oral medication administered within one hour of the start of administration of GaviLyte-G may be flushed from the gastrointestinal tract and the medication may not be absorbed properly.

Concurrent use of stimulant laxatives and GaviLyte-G may increase the risk of mucosal ulceration or ischemic colitis. Avoid use of stimulant laxatives (e.g., bisacodyl, sodium picosulfate) while taking GaviLyte-G.

The primary mode of action is thought to be through the osmotic effect of polyethylene glycol 3350 which causes water to be retained in the colon and produces a watery stool.

GaviLyte-G induces as diarrhea which rapidly cleanses the bowel, usually within four hours.

The pharmacokinetics of PEG3350 following administration of GaviLyte-G were not assessed. Available pharmacokinetic information for oral PEG3350 suggests that it is poorly absorbed.

Long term studies in animals have not been performed to evaluate carcinogenic potential of GaviLyte-G. Studies to evaluate the possible impairment of fertility or mutagenic potential of GaviLyte-G have not been performed.