Sitagliptin is a new oral hypoglycemic (anti-diabetic drug) of the new dipeptidyl peptidase-4 (DPP-4) inhibitor class of drugs. This enzyme-inhibiting drug is to be used either alone or in combination with metformin or a thiazolidinedione for control of type 2 diabetes mellitus. The drug works to competitively inhibit a protein/enzyme, dipeptidyl peptidase 4 (DPP-4), that results in an increased amount of active incretins (GLP-1 and GIP), the reduced amount of release of glucagon (diminishes its release) and increased release of insulin.
Mechanism of Action of Sitagliptin
Sitagliptin works to competitively inhibit the enzyme dipeptidyl peptidase 4 (DPP-4). This enzyme breaks down the incretins GLP-1 and GIP, gastrointestinal hormones released in response to a meal. By preventing GLP-1 and GIP inactivation, they are able to increase the secretion of insulin and suppress the release of glucagon by the alpha cells of the pancreas. This drives blood glucose levels towards normal. As the blood glucose level approaches normal, the amounts of insulin released and glucagon suppressed diminishes, thus tending to prevent an “overshoot” and subsequent low blood sugar (hypoglycemia) which is seen with some other oral hypoglycemic agents. Sitagliptin has been shown to lower HbA1c level by about 0.7% points versus placebo. It is slightly less effective than metformin when used as a monotherapy. It does not cause weight gain and has less hypoglycemia compared to sulfonylureas. Sitagliptin is recommended as a second line drug (in combination with other drugs) after the combination of diet/exercise and metformin fails.
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Sitagliptin is a DPP-4 inhibitor, which is believed to exert its actions in patients with type 2 diabetes by slowing the inactivation of incretin hormones. Concentrations of the active intact hormones are increased by Januvia, thereby increasing and prolonging the action of these hormones. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released by the intestine throughout the day, and levels are increased in response to a meal. These hormones are rapidly inactivated by the enzyme, DPP-4. The incretins are part of an endogenous system involved in the physiologic regulation of glucose homeostasis. When blood glucose concentrations are normal or elevated, GLP-1 and GIP increase insulin synthesis and release from pancreatic beta cells by intracellular signaling pathways involving cyclic AMP. GLP-1 also lowers glucagon secretion from pancreatic alpha cells, leading to reduced hepatic glucose production. By increasing and prolonging active incretin levels, Januvia increases insulin release and decreases glucagon levels in the circulation in a glucose-dependent manner. Sitagliptin demonstrates selectivity for DPP-4 and does not inhibit DPP-8 or DPP-9 activity in vitro at concentrations approximating those from therapeutic doses.
Indications of Sitagliptin
- Type 2 Diabetes Mellitus
- As an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus.
- For use as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus.
- Also for use in patients with type 2 diabetes mellitus to improve glycemic control in combination with metformin or a PPARγ agonist (e.g., thiazolidinediones) when the single agent alone, with diet and exercise, does not provide adequate glycemic control.
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For adult patients with type 2 diabetes mellitus, is indicated to improve glycaemic control
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As monotherapy in patients inadequately controlled by diet and exercise alone and for whom metformin is inappropriate due to contraindications or intolerance.
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As dual oral therapy in combination with metformin when diet and exercise plus metformin alone do not provide adequate glycaemic control.
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A sulphonylurea when diet and exercise plus maximally tolerated dose of a sulphonylurea alone do not provide adequate glycaemic control and when metformin is inappropriate due to contraindications or intolerance.
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A peroxisome proliferator-activated receptor gamma (PPARy) agonist (i.e. a thiazolidinedione) when use of a PPARy agonist is appropriate and when diet and exercise plus the PPARy agonist alone do not provide adequate glycaemic control.
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As triple oral therapy in combination with sulphonylurea and metformin when diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control.
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a PPARy agonist and metformin when use of a PPARy agonist is appropriate and when diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control.
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TESAVEL is also indicated as add-on to insulin (with or without metformin) when diet and exercise plus stable dose of insulin do not provide adequate glycaemic control.For adult patients with type 2 diabetes mellitus, Xelevia is indicated to improve glycaemic control
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As monotherapy in patients inadequately controlled by diet and exercise alone and for whom metformin is inappropriate due to contraindications or intolerance.
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As dual oral therapy in combination with metformin when diet and exercise plus metformin alone do not provide adequate glycaemic control.
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Sulphonylurea when diet and exercise plus maximal tolerated dose of a sulphonylurea alone do not provide adequate glycaemic control and when metformin is inappropriate due to contraindications or intolerance.
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A peroxisome proliferator-activated receptor gamma (PPAR) agonist (i.e. a thiazolidinedione) when use of a PPAR agonist is appropriate and when diet and exercise plus the PPAR agonist alone do not provide adequate glycaemic control.
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As triple oral therapy in combination with a sulphonylurea and metformin when diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control.a PPAR agonist and metformin when use of a PPAR agonist is appropriate and when diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control.
Contra-Indications of Sitagliptin
- Infection
- Low blood sugar
- Pituitary hormone deficiency
- Decreased function of the adrenal gland
- Inadequate vitamin B12
- Excess body acid
- Extreme loss of body water
- Habit of drinking too much alcohol
- Alcohol intoxication
- Heart attack
- Suddenly serious symptoms of heart failure
- Liver problems
- Recent operation
- Fever
- Shock
- Severe vomiting
- Severe diarrhea
- Serious lack of oxygen in the blood
- Weakened patient
- Injury
- Sepsis syndrome
- X-Ray Study with intravenous iodine contrast agent
- Kidney disease with likely reduction in kidney function
- Acute inflammation of the pancreas
- Chronic inflammation of the pancreas
- Moderate to Severe kidney impairment
Dosage of Sitagliptin
Strengths: 50 mg; 25 mg; 100 mg
Diabetes Type 2
- Usual dose: 100 mg orally once a day
Side Effects of Sitagliptin
Most common
- abdominal pain,
- physical weakness (asthenia)
- diarrhea
- gas (flatulence)
- symptoms of weakness, muscle pain (myalgia)
- upper respiratory tract infection
- low blood sugar (hypoglycemia)
- abdominal pain (GI complaints), lactic acidosis (rare)
- low blood levels of vitamin B-12
- nausea,vomiting
- chest discomfort
- chills, dizziness
- bloating/abdominal distention
- constipation
- heartburn
More common
- Abdominal or stomach discomfort
- cough or hoarseness
- decreased appetite
- diarrhea
- fast or shallow breathing
- fever or chills
- general feeling of discomfort
- lower back or side pain
- muscle pain or cramping
- painful or difficult urination
Less common
- Abnormal stools
- bad, unusual, or unpleasant (after) taste
- change in taste
- difficulty with moving
- discoloration of the fingernails or toenails
- flu-like symptoms
- joint pain
- rash
- runny nose
- sneezing
- stuffy nose
- swollen joints
Drug Interactions of Sitagliptin
Sitagliptin may interact with following drugs, supplements & may decrease the efficacy of drug
- angiotensin-converting enzyme inhibitors (ACEIs; captopril, enalapril,ramipril)
- alcohol
- antipsychotic medications (e.g., chlorpromazine, haloperidol, olanzapine,
- birth control pills
- bupropion
- atorvastatin
- cyclosporine
- dabrafenib
- corticosteroids (e.g., dexamethasone, prednisone)
- diabetic drugs (e.g., glyburide, insulin, repaglinide, sitagliptin)
- diuretics (e.g., furosemide, hydrochlorothiazide)
- HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
- iodinated contrast material
- phenytoin
- quinolone antibiotics (e.g., levofloxacin, moxifloxacin)
- selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, sertraline paroxetine,
- trimethoprim
- sulfonamide antibiotics (“sulfas”; e.g., sulfisoxazole, sulfamethoxazole)
- somatotropin
- sulfamethoxazole
- testosterone
- verapamil
Pregnancy & Lactation of Sitagliptin
FDA Pregnancy Category B
Pregnancy
This medication is not recommended for use during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding
It is not known if sitagliptin passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
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