PANSIPTIN 50

Indications

• Constipation
• Dietary fiber supplementation
• Irritable bowel syndrome
• Diverticular disease
• Weight management

Dosage

Children: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Adults: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Mechanism of action

Cellulose acts primarily as a bulk-forming laxative. It absorbs water in the intestines, which increases stool bulk and stimulates peristalsis, thus facilitating bowel movements. Additionally, cellulose is not digestible by human enzymes, leading to fermentation by gut bacteria, which may enhance gut health and alter gut microbiota composition.

Pharmacodynamics

Cellulose increases stool weight and frequency of bowel movements. It works by retaining water in the intestines, leading to softer stools and improved passage through the gastrointestinal tract. The bulking effect of cellulose can help alleviate constipation and promote overall digestive health. It may also play a role in cholesterol reduction and glycemic control through its effects on digestion and absorption of nutrients.

Pharmacokinetics

Cellulose is not absorbed into the bloodstream due to its indigestible nature. Instead, it passes through the gastrointestinal tract, where it adds bulk to the stool. Its fermentation by colonic bacteria produces short-chain fatty acids, which may have beneficial effects on colon health. The onset of action for cellulose as a laxative can vary but is generally within 24 to 72 hours after ingestion.

Adverse effects

• Bloating
• Flatulence
• Diarrhea
• Abdominal discomfort

Precautions

• Use with caution in patients with a history of gastrointestinal disorders.
• Monitor for potential allergic reactions in sensitive individuals.

Pregnancy

Cellulose is generally considered safe during pregnancy as it is a non-toxic, indigestible fiber.

Breast-feeding

Cellulose is also considered safe during breastfeeding; it is excreted in breast milk in negligible amounts.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Powder
• Capsules
• Tablets
• Granules

Indications

• Protection of drugs from degradation
• Taste masking
• Controlled release of active ingredients
• Improvement of patient compliance
• Targeted delivery of medications

Dosage

Children: Refer to specific product labeling for dosing information, as this varies widely based on formulation and indication.

Adults: Refer to specific product labeling for dosing information, as this varies widely based on formulation and indication.

Mechanism of action

The mechanism of action of coatings primarily involves the modification of drug release profiles. By altering the solubility and permeability of the drug through the coating material, the release rate can be controlled. For example, enteric coatings prevent drug dissolution in the acidic environment of the stomach, allowing the drug to be released in the more neutral pH of the intestine.

Pharmacodynamics

Pharmacodynamics of coated formulations can vary significantly based on the type of coating used. Immediate-release coatings dissolve quickly, leading to rapid absorption and onset of action. Controlled-release coatings are designed to dissolve slowly over time, providing a sustained release of the drug, which can lead to prolonged therapeutic effects and reduced dosing frequency. The choice of coating material and thickness influences the overall pharmacodynamic profile of the drug.

Pharmacokinetics

The pharmacokinetics of coated drugs are influenced by the coating material and the drug itself. Factors such as the rate of dissolution, absorption site, and first-pass metabolism play critical roles. Coatings can alter the bioavailability and distribution of the drug. For example, enteric coatings can enhance the absorption of drugs that are unstable in acidic conditions, potentially increasing their bioavailability when the drug reaches the intestine.

Pregnancy

Safety in pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised as it is not known whether it passes into breast milk.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Indications

• Hypovolemic shock
• Severe burns
• Postoperative fluid replacement
• Sepsis
• Trauma management

Dosage

Children: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Adults: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Mechanism of action

Colloidal solutions work by maintaining oncotic pressure in the blood, thus helping to retain fluid within the vascular system. This is primarily due to the large molecular weight of the colloidal particles, which cannot easily pass through capillary walls. The presence of colloids in the blood helps to draw water into the circulation, increasing blood volume and improving tissue perfusion.

Pharmacodynamics

The pharmacodynamics of colloidal solutions are centered on their ability to exert osmotic pressure, which helps maintain blood volume and pressure. This effect is particularly important in conditions such as hypovolemia and shock, where fluid replacement is necessary to restore hemodynamic stability. The efficacy of colloidal solutions can vary depending on the type of colloid used, as well as the underlying clinical condition being treated.

Pharmacokinetics

Colloidal solutions are typically administered intravenously and their pharmacokinetics can vary based on the specific formulation. Generally, colloids are distributed throughout the vascular compartment and have a longer duration of action compared to crystalloids, as they remain in circulation longer. The elimination of colloids is primarily through the reticuloendothelial system, where they are metabolized or eliminated by the liver and spleen. Factors such as particle size and composition can influence their distribution and clearance.

Adverse effects

• Allergic reactions
• Injection site reactions
• Nausea
• Vomiting
• Headache
• Fever

Precautions

• Use with caution in patients with known allergies to any component of the formulation
• Monitor for signs of hypersensitivity during administration
• Consider volume overload in patients with cardiac or renal impairment

Pregnancy

The safety of colloidal solutions during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether colloidal solutions are excreted in human milk. Caution should be exercised when administering to breastfeeding mothers.

Storage

Store at room temperature, protect from light, and do not freeze. Keep out of reach of children.

Formulations

• Colloidal silver
• Colloidal gold
• Colloidal iron
• Other metal colloids

Indications

• Used as a disintegrant in tablet formulations
• Improves dissolution of active pharmaceutical ingredients
• Facilitates the breakdown of solid dosage forms

Dosage

Children: Refer to specific product information for dosing guidelines, as croscarmelose is used as an excipient and not dosed independently.

Adults: Refer to specific product information for dosing guidelines, as croscarmelose is used as an excipient and not dosed independently.

Mechanism of action

Croscarmelose functions by rapidly absorbing water and swelling upon hydration. This swelling action creates pressure within the tablet, leading to disintegration into smaller particles. The increased surface area of the drug particles enhances dissolution and absorption in the gastrointestinal tract, ultimately improving the pharmacokinetic profile of the active ingredients.

Pharmacodynamics

As a disintegrant, croscarmelose does not exert a pharmacological effect on its own but plays a critical role in the formulation of oral solid dosage forms. Its pharmacodynamic properties are primarily related to its ability to facilitate the release of active ingredients from their dosage forms, thereby influencing the onset and duration of action of the administered medication.

Pharmacokinetics

Croscarmelose is not absorbed systemically when ingested, as it functions primarily within the gastrointestinal tract. It is excreted unchanged in the feces following its role in aiding the dissolution and disintegration of solid dosage forms. Its safety profile is well-established, and it is considered non-toxic, with minimal adverse effects when used in recommended amounts.

Pregnancy

Croscarmelose is generally considered safe for use during pregnancy as it is an inert substance and does not have systemic effects.

Breast-feeding

Croscarmelose is not absorbed systemically and is considered safe for use during breastfeeding.

Storage

Store in a cool, dry place, away from direct sunlight and moisture.

Formulations

• Tablet
• Capsule
• Powder

Dosage

Children: Refer to specific formulations and clinical guidelines for dosing information as this can vary widely based on the context of use.

Adults: Refer to specific formulations and clinical guidelines for dosing information as this can vary widely based on the context of use.

Mechanism of action

Dibasic compounds often act by providing a buffering effect in biological systems, which helps to maintain physiological pH levels. They may also interact with various biological targets depending on their specific structure, influencing metabolic pathways and cellular functions.

Pharmacodynamics

The pharmacodynamics of dibasic compounds is highly variable and depends on their specific chemical structure and the context of their use. Generally, these compounds may alter the absorption and distribution of other drugs, modulate enzyme activity, or affect cellular signaling pathways through their interactions with biological molecules.

Pharmacokinetics

The pharmacokinetics of dibasic compounds can vary widely. Factors such as solubility, stability, and route of administration influence their absorption, distribution, metabolism, and excretion. Typically, dibasic compounds may be absorbed in the gastrointestinal tract and may undergo various metabolic processes depending on their specific nature.

Pregnancy

Dibasic compounds should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult with a healthcare provider.

Breast-feeding

Caution is advised when administering dibasic compounds to breastfeeding mothers. Consult with a healthcare provider.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Used as an excipient in tablet formulations
• Used as a bulking agent in capsule formulations
• Used in food products as a thickener or stabilizer

Dosage

Children: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Adults: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Mechanism of action

Microcrystalline cellulose acts as a non-digestible filler that enhances the flow properties of powders during the manufacturing of tablets and capsules. It does not have a direct pharmacological action on the body but ensures that the active ingredients are effectively delivered to the patient.

Pharmacodynamics

As a non-active ingredient, microcrystalline cellulose does not exert pharmacodynamic effects typical of active pharmaceutical ingredients. Its primary role is to provide a stable and consistent matrix for the drug, facilitating the release of the active compound once ingested.

Pharmacokinetics

Microcrystalline cellulose is not absorbed in the gastrointestinal tract; it passes through the digestive system largely unchanged. It adds bulk to the stool, which may aid in promoting regular bowel movements. The substance is excreted in feces, where it contributes to dietary fiber intake.

Pregnancy

Data regarding the use of microcrystalline cellulose during pregnancy is limited. It is advisable to consult with healthcare professionals before use.

Breast-feeding

Microcrystalline cellulose is considered safe during breastfeeding, as it is not absorbed systemically.

Storage

Store in a cool, dry place away from direct sunlight and moisture.

Dosage

Children: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Adults: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Mechanism of action

The mechanism of action for purified compounds varies widely depending on the specific substance. Generally, purified drugs exert their effects by interacting with specific biological targets, such as receptors, enzymes, or ion channels, leading to a desired therapeutic effect. This interaction can involve binding to receptors to activate or inhibit signaling pathways, modulating enzymatic activity, or altering physiological processes.

Pharmacodynamics

Pharmacodynamics describes the effects of a drug on the body and the relationship between drug concentration and effect. For purified drugs, this can involve dose-response relationships and the time course of their action. The purified form often enhances potency and reduces variability in response among patients, which can lead to more predictable therapeutic outcomes. The overall effect is determined by the drug's affinity for its target, the efficacy of the drug-receptor interaction, and the downstream signaling pathways activated as a result of this interaction.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of a drug. For purified substances, absorption can be more efficient due to the absence of impurities that may affect solubility or stability. Distribution may also be enhanced, leading to higher bioavailability. Metabolism can be influenced by the structure of the purified compound, as it may be metabolized more readily by liver enzymes. Excretion typically occurs through the kidneys or liver, depending on the molecular characteristics of the purified drug.

Pregnancy

Consult with a healthcare professional, as the safety of purified forms of medications during pregnancy may vary depending on the specific substance.

Breast-feeding

Consult with a healthcare professional, as the safety of purified forms of medications during breastfeeding may vary depending on the specific substance.

Storage

Store in a cool, dry place, away from light and moisture, and keep out of reach of children.

Indications

• Pain relief
• Inflammation reduction
• Fever reduction
• Bacterial infections

Dosage

Children: Always refer to BNF for Children for appropriate dosing based on age and weight.

Adults: Refer to specific product guidelines for precise dosing information based on the formulation and condition being treated.

Mechanism of action

The mechanism of action for the active ingredients in Ready can vary. For instance, if it includes non-steroidal anti-inflammatory drugs (NSAIDs), these work by inhibiting the cyclooxygenase (COX) enzymes, leading to a decrease in the synthesis of prostaglandins, which are mediators of inflammation and pain. If the formulation includes antibiotics, these can work by targeting bacterial cell wall synthesis, protein synthesis, or other bacterial metabolic processes, leading to bacterial cell death.

Pharmacodynamics

Pharmacodynamics will depend on the specific active ingredients within Ready. Generally, NSAIDs exhibit anti-inflammatory, analgesic, and antipyretic effects through their action on COX enzymes. Antibiotics may demonstrate bactericidal or bacteriostatic effects, depending on their class and mechanism of action. The overall effect is a reduction in symptoms associated with infections, inflammation, or pain.

Pharmacokinetics

The pharmacokinetics of Ready will also vary based on the individual components. Typically, NSAIDs are rapidly absorbed, with peak plasma concentrations occurring within a few hours post-administration. They are metabolized primarily in the liver and excreted via the kidneys. Antibiotics may have various absorption rates depending on their formulation, distribution, metabolism, and excretion characteristics, which influence their efficacy and safety profile.

Pregnancy

Consult healthcare provider for use during pregnancy. The effects on fetal development are not well established.

Breast-feeding

Consult healthcare provider before use. The excretion in breast milk is not well studied.

Storage

Store in a cool, dry place, away from direct sunlight. Keep out of reach of children.

Indications

• Silicosis
• Chronic obstructive pulmonary disease (COPD)
• Lung cancer associated with silica exposure

Dosage

Adults: Silica is not administered as a drug, but rather

Mechanism of action

Silica, particularly crystalline forms like quartz and cristobalite, can induce cytotoxicity and morphological transformation in cells. The cytotoxic effects are attributed to the presence of silanol groups and trace iron on the silica surface, which can generate reactive oxygen species. These interactions lead to cellular damage and transformation, suggesting multiple molecular mechanisms underlying silica's biological effects. The activity is sensitive to the silica's surface structure and composition, indicating that the biological response is a phenomenon originating from the silica's surface characteristics.

Pharmacodynamics

Silica's pharmacodynamic effects are largely related to its cytotoxic and transforming properties, particularly in lung tissue. The inhalation of crystalline silica can lead to the activation of inflammatory pathways, oxidative stress, and apoptosis in alveolar macrophages and epithelial cells. This can result in chronic inflammation, fibrosis, and ultimately, diseases such as silicosis and lung cancer. The degree of these effects varies based on the type of silica, its crystalline structure, and the presence of surface modifications.

Pharmacokinetics

The pharmacokinetics of silica is complex as it is not absorbed systemically when inhaled or ingested. Instead, inhaled silica particles can deposit in the alveolar region of the lungs, where they may persist for long periods. The body responds to silica exposure through inflammatory processes, and macrophages attempt to phagocytize silica particles. However, the persistence of these particles can lead to chronic lung conditions. Clearance mechanisms are inefficient, leading to prolonged retention in lung tissue.

Adverse effects

• Cytotoxicity
• Morphological transformation of cells
• Respiratory issues
• Silicosis
• Lung cancer

Precautions

• Use caution in occupational settings with silica dust exposure
• Regular monitoring of lung function in exposed individuals

Pregnancy

There is insufficient data on the effects of silica on pregnancy. It is advised to minimize exposure.

Breast-feeding

Limited data available; caution is advised due to potential respiratory effects.

Storage

Store in a cool, dry place, away from moisture and incompatible materials.

Formulations

• Crystalline silica
• Amorphous silica (diatomaceous earth)
• Silica gel

Indications

• Type 2 diabetes mellitus as monotherapy (if metformin is inappropriate)
• Type 2 diabetes mellitus in combination with other antidiabetic drugs (including insulin) when metformin alone or in combination fails to achieve adequate glycemic control

Dosage

Adults: 100 mg once daily, or 50 mg twice daily when used in combination with a sulfonylurea or insulin. Dose adjustments may be required based on renal function.

Mechanism of action

Sitagliptin inhibits the enzyme dipeptidyl peptidase-4 (DPP-4), which is responsible for the degradation of incretin hormones. This inhibition results in prolonged active incretin levels, which enhances insulin secretion from pancreatic beta cells and decreases glucagon secretion from alpha cells in the pancreas, leading to lowered blood glucose levels.

Pharmacodynamics

Sitagliptin's pharmacodynamic effects include improved glycemic control, characterized by reduced fasting and postprandial blood glucose levels. The drug is effective in lowering HbA1c levels and is associated with a low risk of hypoglycemia. It has a beneficial effect on weight management, as it typically does not promote weight gain.

Pharmacokinetics

Sitagliptin is absorbed rapidly after oral administration, with peak plasma concentrations occurring within 1-4 hours. Its bioavailability is approximately 87%. The drug is predominantly eliminated via renal excretion, with about 80% of the dose excreted unchanged in the urine. The elimination half-life is approximately 12.4 hours. Renal impairment may necessitate dose adjustments, as clearance is significantly reduced in patients with decreased renal function.

Contra-indications

• History of pancreatitis
• Severe heart failure

Adverse effects

• Headache
• Constipation
• Dizziness
• Skin reactions
• Angioedema
• Back pain
• Cutaneous vasculitis
• Joint disorders
• Myalgia
• Acute pancreatitis
• Acute renal impairment
• Stevens-Johnson syndrome
• Vomiting

Interactions

• Concomitant use with sulfonylureas or insulin may require dose adjustments
• Moderate interaction with vemurafenib (increases exposure)

Precautions

• Monitor renal function before treatment and periodically thereafter
• Discontinue if symptoms of acute pancreatitis occur, such as persistent severe abdominal pain

Pregnancy

Avoid-toxicity observed in animal studies.

Breast-feeding

Avoid-present in milk in animal studies.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Tablets: 50 mg, 100 mg

Indications

• Dry skin conditions
• Cosmetic formulations
• Emollient in topical creams and lotions
• Emulsifying agent in pharmaceutical preparations

Dosage

Children: For pediatric use, refer to specific product formulations and guidelines, as dosing may vary based on the formulation and concentration.

Adults: Stearyl alcohol is used topically in various formulations. Specific dosing is typically determined by the formulation and intended use, refer to product guidelines for detailed instructions.

Mechanism of action

Stearyl alcohol functions primarily as an emollient and emulsifier. It aids in the formation of stable emulsions by reducing the surface tension between oil and water phases, allowing for the creation of creams and lotions. Its hydrophobic tail interacts with lipids, while the hydroxyl group can form hydrogen bonds with water, enhancing moisture retention in the skin.

Pharmacodynamics

Stearyl alcohol acts by providing a protective barrier on the skin, reducing transepidermal water loss and enhancing hydration. Its emollient properties make it effective in softening and smoothing the skin, which can alleviate dryness and improve the overall appearance of the skin. Additionally, it can enhance the delivery of other active ingredients in topical formulations.

Pharmacokinetics

Stearyl alcohol is not significantly absorbed systemically when applied topically. Its primary action is local to the site of application, where it exerts its emollient effects. The compound is metabolized in the body to various fatty acids and alcohols, and it is excreted primarily through the skin and gastrointestinal tract, with minimal systemic exposure.

Pregnancy

Stearyl is generally considered safe for use during pregnancy; however, specific formulations should be evaluated for their ingredients.

Breast-feeding

Stearyl can be used while breastfeeding, but it's recommended to consult a healthcare provider for specific concerns regarding topical applications.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Cream
• Ointment
• Lotion

Mechanism of action

...Some quartz and cristobalite dusts (crystalline) as well as the diatomaceous earths (amorphous), but not the pyrogenic amorphous silica, were cytotoxic and induced morphological transformation of SHE cells in a concentration-dependent manner. The ranking in cytotoxicity was different from that in transforming potency, suggesting two separate molecular mechanisms for the two effects. The cytotoxic and transforming potencies were different from one dust to another, even among the same structural silicas. The type of crystalline structure (quartz vs cristobalite) and the crystalline vs biogenic amorphous form did not correlate with cytotoxic or transforming potency of silica dusts. Comparison of cellular effects induced by original and surface modified samples revealed that several surface functionalities modulate cytotoxic and transforming potencies. The cytotoxic effects appeared to be related to the distribution and abundance of silanol groups and to the presence of trace amounts of iron on the silica surface. Silica particles with fractured surfaces and/or iron-active sites, able to generate reactive oxygen species, induced SHE cell transformation. The results show that the activity of silica at the cellular level is sensitive to the composition and structure of surface functionalities and confirm that the biological response to silica is a surface originated phenomenon. In vivo exposure of rat lungs to crystalline silica either by intratracheal instillation or by inhalation results in an increase in mRNA levels for inducible nitric oxide synthase (iNOS) in bronchoalveolar lavage cells (BALC), elevated nitric oxide (.NO) production by BALC, and an increase in .NO-dependent chemiluminescence (CL) from alveolar macrophages (AM). Induction of iNOS message occurs in both AM and polymorphonuclear leukocytes (PMN) harvested from silica-exposed lungs but is not significantly elevated in lavaged lung tissue. This review presents characteristics of simple and complicated coal workers' pneumoconiosis (CWP) as well as pathologic indices of acute and chronic silicosis by summarizing results of in vitro, animal, and human investigations. These results support four basic mechanisms in the etiology of CWP and silicosis: a) direct cytotoxicity of coal dust or silica, resulting in lung cell damage, release of lipases and proteases, and eventual lung scarring; b) activation of oxidant production by pulmonary phagocytes, which overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury, and lung scarring; c) activation of mediator release from alveolar macrophages and epithelial cells, which leads to recruitment of polymorphonuclear leukocytes and macrophages, resulting in the production of proinflammatory cytokines and reactive species and in further lung injury and scarring; d) secretion of growth factors from alveolar macrophages and epithelial cells, stimulating fibroblast proliferation and eventual scarring. Results of in vitro and animal studies provide a basis for proposing these mechanisms for the initiation and progression of pneumoconiosis. Data obtained from exposed workers lend support to these mechanisms. /The authors/ reported previously that freshly fractured silica (FFSi) induces activator protein-1 (AP-1) activation through extracellular signal-regulated protein kinases (ERKs) and p38 kinase pathways. In the present study, the biologic activities of FFSi and aged silica (ASi) were compared by measuring their effects on the AP-1 activation and phosphorylation of ERKs and p38 kinase. The roles of reactive oxygen species (ROS) in this silica-induced AP-1 activation were also investigated. FFSi-induced AP-1 activation was four times higher than that of ASi in JB6 cells. FFSi also caused greater phosphorylation of ERKs and p38 kinase than ASi. FFSi generated more ROS than ASi when incubated with the cells as measured by electron spin resonance (ESR). Studies using ROS-sensitive dyes and

Mechanism of action

Inhibition of DPP-4 by sitagliptin slows DPP-4 mediated inactivation of incretins like GLP-1 and GIP. Incretins are released throughout the day and upregulated in response to meals as part of glucose homeostasis. Reduced inhibition of incretins increase insulin synthesis and decrease glucagon release in a manner dependant on glucose concentrations. These effects lead to an overall increase in blood glucose control which is demonstrated by reduced glycosylated hemoglobin (HbA1c). Januvia is a member of a class of oral anti-hyperglycemic agents called dipeptidyl peptidase 4 (DPP-4) inhibitors. The improvement in glycemic control observed with this medicinal product may be mediated by enhancing the levels of active incretin 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. 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. Treatment with GLP-1 or with DPP-4 inhibitors in animal models of type 2 diabetes has been demonstrated to improve beta cell responsiveness to glucose and stimulate insulin biosynthesis and release. With higher insulin levels, tissue glucose uptake is enhanced. In addition, GLP-1 lowers glucagon secretion from pancreatic alpha cells. Decreased glucagon concentrations, along with higher insulin levels, lead to reduced hepatic glucose production, resulting in a decrease in blood glucose levels. The effects of GLP-1 and GIP are glucose-dependent such that when blood glucose concentrations are low, stimulation of insulin release and suppression of glucagon secretion by GLP-1 are not observed. For both GLP-1 and GIP, stimulation of insulin release is enhanced as glucose rises above normal concentrations. Further, GLP-1 does not impair the normal glucagon response to hypoglycemia. The activity of GLP-1 and GIP is limited by the DPP-4 enzyme, which rapidly hydrolyzes the incretin hormones to produce inactive products. Sitagliptin prevents the hydrolysis of incretin hormones by DPP-4, thereby increasing plasma concentrations of the active forms of GLP-1 and GIP. By enhancing active incretin levels, sitagliptin increases insulin release and decreases glucagon levels in a glucose-dependent manner. In patients with type 2 diabetes with hyperglycemia, these changes in insulin and glucagon levels lead to lower hemoglobin A1c (HbA1c) and lower fasting and postprandial glucose concentrations. The glucose-dependent mechanism of sitagliptin is distinct from the mechanism of sulfonylureas, which increase insulin secretion even when glucose levels are low and can lead to hypoglycemia in patients with type 2 diabetes and in normal subjects. Sitagliptin is a potent and highly selective inhibitor of the enzyme DPP-4 and does not inhibit the closely-related enzymes DPP-8 or DPP-9 at therapeutic concentrations. 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

Pharmacodynamics

Sitagliptin inhibits DPP-4 which leads to increased levels of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide(GIP), decreased levels of glucagon, and a stronger insulin response to glucose.