Linarol-M

Uses

This is used for an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus when treatment with both linagliptin and metformin is appropriate.

Linarol-M is also used to associated treatment for these conditions: Type 2 Diabetes MellitusPolycystic Ovaries Syndrome, Type 2 Diabetes Mellitus, Glycemic Control

How Linarol-M works

Linagliptin is a competitive, reversible DPP-4 inhibitor. Inhibition of this enzyme slows the breakdown of GLP-1 and glucose-dependant insulinotropic polypeptide (GIP). GLP-1 and GIP stimulate the release of insulin from beta cells in the pancreas while inhibiting release of glucagon from pancreatic beta cells. These effects together reduce the breakdown of glycogen in the liver and increase insulin release in response to glucose.

Metformin's mechanisms of action are unique from other classes of oral antihyperglycemic drugs. Metformin decreases blood glucose levels by decreasing hepatic glucose production (gluconeogenesis), decreasing the intestinal absorption of glucose, and increasing insulin sensitivity by increasing peripheral glucose uptake and utilization . It is well established that metformin inhibits mitochondrial complex I activity, and it has since been generally postulated that its potent antidiabetic effects occur through this mechanism . The above processes lead to a decrease in blood glucose, managing type II diabetes and exerting positive effects on glycemic control.

After ingestion, the organic cation transporter-1 (OCT1) is responsible for the uptake of metformin into hepatocytes (liver cells). As this drug is positively charged, it accumulates in cells and in the mitochondria because of the membrane potentials across the plasma membrane as well as the mitochondrial inner membrane. Metformin inhibits mitochondrial complex I, preventing the production of mitochondrial ATP leading to increased cytoplasmic ADP:ATP and AMP:ATP ratios . These changes activate AMP-activated protein kinase (AMPK), an enzyme that plays an important role in the regulation of glucose metabolism . Aside from this mechanism, AMPK can be activated by a lysosomal mechanism involving other activators. Following this process, increases in AMP:ATP ratio also inhibit fructose-1,6-bisphosphatase enzyme, resulting in the inhibition of gluconeogenesis, while also inhibiting adenylate cyclase and decreasing the production of cyclic adenosine monophosphate (cAMP) , a derivative of ATP used for cell signaling . Activated AMPK phosphorylates two isoforms of acetyl-CoA carboxylase enzyme, thereby inhibiting fat synthesis and leading to fat oxidation, reducing hepatic lipid stores and increasing liver sensitivity to insulin .

In the intestines, metformin increases anaerobic glucose metabolism in enterocytes (intestinal cells), leading to reduced net glucose uptake and increased delivery of lactate to the liver. Recent studies have also implicated the gut as a primary site of action of metformin and suggest that the liver may not be as important for metformin action in patients with type 2 diabetes. Some of the ways metformin may play a role on the intestines is by promoting the metabolism of glucose by increasing glucagon-like peptide I (GLP-1) as well as increasing gut utilization of glucose .

In addition to the above pathway, the mechanism of action of metformin may be explained by other ways, and its exact mechanism of action has been under extensive study in recent years .

Dosage

Linarol-M dosage

The dosageshould be individualized on the basis of both effectiveness and tolerability. Maximum recommended dose of 2.5 mg Linagliptin and 1000 mg Metformin Hydrochloride twice daily with meals. Dose escalation should be gradual to reduce the gastrointestinal (GI) side effects associated with Metformin use.

Recommended starting dose:In patients currently not treated with Metformin, initiate treatment with 2.5 mg Linagliptin and 500 mg Metformin Hydrochloride twice daily. In patients already treated with Metformin, start with 2.5 mg Linagliptin and the current dose of Metformin Hydrochloride twice daily. Patients already treated with linagliptin and metformin, individual components may be switched to this combination containing the same doses of each component.

Pediatric patients: Safety and effectiveness of Linagliptin in patients below the age of 18 have not been established.

Renal or hepatic impairment: No dose adjustment required.

Side Effects

Most common side effects are nasopharyngitis and diarrhea. Hypoglycemia is more common in patients treated with this combination and sulfonylureas.

Toxicity

No dosage adjustment is necessary based on race, age, weight, sex, renal impairment, or hepatic impairment.

Studies of efficacy and safety in pediatric populations were not included in the original drug approval but recent clinical trials show linagliptin to be well tolerated in patients 10 to 18 years old.

Animal studies showed an increased risk of lymphoma in female rats at over 200 times the clinical dose. Aside from this effect, linagliptin was not shown to be mutagenic, clastogenic, or have an effect on fertility.

Metformin (hydrochloride) toxicity data:

Oral LD50 (rat): 1 g/kg; Intraperitoneal LD50 (rat): 500 mg/kg; Subcutaneous LD50 (rat): 300 mg/kg; Oral LD50 (mouse): 1450 mg/kg; Intraperitoneal LD50 (mouse): 420 mg/kg; Subcutaneous LD50 (mouse): 225 mg/kg .

A note on lactic acidosis

Metformin decreases liver uptake of lactate, thereby increasing lactate blood levels which may increase the risk of lactic acidosis . There have been reported postmarketing cases of metformin-associated lactic acidosis, including some fatal cases. Such cases had a subtle onset and were accompanied by nonspecific symptoms including malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence. In certain cases, hypotension and resistant bradyarrhythmias have occurred with severe lactic acidosis . Metformin-associated lactic acidosis was characterized by elevated blood lactate concentrations (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), as well as an increased lactate:pyruvate ratio; metformin plasma levels were generally >5 mcg/mL.

Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment .

A note on renal function

In patients with decreased renal function, the plasma and blood half-life of metformin is prolonged and the renal clearance is decreased .

Metformin should be avoided in those with severely compromised renal function (creatinine clearance < 30 ml/min), acute/decompensated heart failure, severe liver disease and for 48 hours after the use of iodinated contrast dyes due to the risk of lactic acidosis . Lower doses should be used in the elderly and those with decreased renal function. Metformin decreases fasting plasma glucose, postprandial blood glucose and glycosolated hemoglobin (HbA1c) levels, which are reflective of the last 8-10 weeks of glucose control. Metformin may also have a positive effect on lipid levels.

A note on hypoglycemia

When used alone, metformin does not cause hypoglycemia, however, it may potentiate the hypoglycemic effects of sulfonylureas and insulin when they are used together .

Use in pregnancy

Available data from post-marketing studies have not indicated a clear association of metformin with major birth defects, miscarriage, or adverse maternal or fetal outcomes when metformin was ingested during pregnancy. Despite this, the abovementioned studies cannot definitively establish the absence of any metformin-associated risk due to methodological limitations, including small sample size and inconsistent study groups .

Use in nursing

A limited number of published studies indicate that metformin is present in human milk. There is insufficient information to confirm the effects of metformin on the nursing infant and no available data on the effects of metformin on the production of milk. The developmental and health benefits of breastfeeding should be considered as well as the mother’s clinical need for metformin and any possible adverse effects on the nursing child .

Precaution

In a patient with lactic acidosis who is taking Metformin, the drug should be discontinued immediately and supportive therapy promptly instituted. There have been postmarketing reports of acute pancreatitis. If pancreatitis is suspected, promptly discontinue Linagliptin & Metformin. Temporarily discontinue Linagliptin & Metformin in patients undergoing radiologic studies with intravascular administration of iodinated contrast materials or any surgical procedures necessitating restricted intake of food and fluids. Metformin may lower Vitamin B12 levels; so hematologic parameters shoud be monitored annually.

Interaction

Cationic drugs (amiloride, digoxin, morphine, ranitidine, trimethoprim etc.): May reduce metformin elimination. P-glycoprotien/CYP3A4 inducer (i.e. rifampin): The efficacy of this medicine may be reduced when administered in combination.

Volume of Distribution

A single intravenous dose of 5mg results in a volume of distribution of 1110L. However an intravenous infusion of 0.5-10mg results in a volume of distribution of 380-1540L.

The apparent volume of distribution (V/F) of metformin after one oral dose of metformin 850 mg averaged at 654 ± 358 L .

Elimination Route

Oral bioavailability of linagliptin is 30%.

Regular tablet absorption

The absolute bioavailability of a metformin 500 mg tablet administered in the fasting state is about 50%-60%. Single-dose clinical studies using oral doses of metformin 500 to 1500 mg and 850 to 2550 mg show that there is a lack of dose proportionality with an increase in metformin dose, attributed to decreased absorption rather than changes in elimination .

At usual clinical doses and dosing schedules of metformin, steady-state plasma concentrations of metformin are achieved within 24-48 hours and are normally measured at Label.

Extended-release tablet absorption

After a single oral dose of metformin extended-release, Cmax is reached with a median value of 7 hours and a range of between 4 and 8 hours. Peak plasma levels are measured to be about 20% lower compared to the same dose of regular metformin, however, the extent of absorption of both forms (as measured by area under the curve - AUC), are similar .

Effect of food

Food reduces the absorption of metformin, as demonstrated by about a 40% lower mean peak plasma concentration (Cmax), a 25% lower area under the plasma concentration versus time curve (AUC), and a 35-minute increase in time to peak plasma concentration (Tmax) after ingestion of an 850 mg tablet of metformin taken with food, compared to the same dose administered during fasting .

Though the extent of metformin absorption (measured by the area under the curve - AUC) from the metformin extended-release tablet is increased by about 50% when given with food, no effect of food on Cmax and Tmax of metformin is observed. High and low-fat meals exert similar effects on the pharmacokinetics of extended-release metformin .

Half Life

The terminal half life of linagliptin is 155 hours.

Approximately 6.2 hours in the plasma and in the blood, the elimination half-life is approximately 17.6 hours, suggesting that the erythrocyte mass may be a compartment of distribution .

Clearance

Total clearance of linagliptin is 374mL/min.

Renal clearance is about 3.5 times greater than creatinine clearance, which indicates that tubular secretion is the major route of metformin elimination. Following oral administration, approximately 90% of the absorbed drug is eliminated via the renal route within the first 24 hours .

Elimination Route

84.7% of linagliptin is eliminated in the feces and 5.4% is eliminated in the urine.

This drug is substantially excreted by the kidney .

Renal clearance of metformin is about 3.5 times higher than creatinine clearance, which shows that renal tubular secretion is the major route of metformin elimination. After oral administration, about 90% of absorbed metformin is eliminated by the kidneys within the first 24 hours post-ingestion .

Pregnancy & Breastfeeding use

Pregnancy category B. There are no adequate and well-controlled studies in pregnant women with this combination or its individual component; so it should be used during pregnancy only if clearly needed. Caution should also be excercised when it is administered to a lactating mother.

Contraindication

Although Linagliptin undergoes minimal renal excretion, Metformin is known to be substantially excreted by the kidney. The risk of Metformin accumulation and lactic acidosis increases with the degree of renal impairment. Therefore, this combination is contraindicated in patients with renal impairment. It is also contraindicated in acute or chronic metabolic acidosis (diabetic ketoacidosis) and in hypersensitivity to Linagliptin or Metformin.

Special Warning

Pediatric Use: Safety and effectiveness of Linagliptin & Metformin combination in pediatric patients under 18 years of age have not been established.

Geriatric Use: Linagliptin is minimally excreted by the kidney; however, Metformin is substantially excreted by the kidney. Considering that aging can be associated with reduced renal function, Linagliptin & Metformin combination should be used with caution as age increases.

Renal Impairment: Studies characterizing the pharmacokinetics of Linagliptin and Metformin after administration of Linagliptin & Metformin combination in renally impaired patients have not been performed. Since Metformin is contraindicated in patients with renal impairment, use of Linagliptin & Metformin combination is also contraindicated in patients with renal impairment (e.g., serum creatinine >=1.5 mg/dL [males] or >=1.4 mg/dL [females], or abnormal creatinine clearance).

Hepatic Impairment: Studies characterizing the pharmacokinetics of Linagliptin and Metformin after administration of Linagliptin & Metformin combination in hepatically impaired patients have not been performed. However, use of Metformin alone in patients with hepatic impairment has been associated with some cases of lactic acidosis. Therefore, use of Linagliptin & Metformin combination is not recommended in patients with hepatic impairment.

Acute Overdose

Hypoglycemia has not been seen with metformin doses up to 85g, although lactic acidosis has occurred in such circumstances. High overdose or concomitant risks of metformin may lead to lactic acidosis. Lactic acidosis is a medical emergency and must be treated in hospital. The most effective method to remove lactate and metformin is hemodialysis.

Storage Condition

Keep in a dry place away from light and heat. Keep out of the reach of children.

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