Januvia (Sitagliptin)

• Januvia is used in the management of type 2 diabetes, a chronic metabolic disorder characterized by insulin resistance.
• Type 2 diabetes mellitus: improves glycaemic control by lowering fasting and post‑prandial blood glucose levels.
• Adjunct to diet and exercise: prescribed when lifestyle measures alone are insufficient to achieve target glucose levels.
• Monotherapy: can be initiated as the first oral agent in newly diagnosed patients.
• Combination therapy: often combined with metformin or other antidiabetic agents to enhance overall glucose control.

• Sitagliptin selectively inhibits the dipeptidyl peptidase‑4 (DPP‑4) enzyme, preventing the breakdown of endogenous incretin hormones such as GLP‑1 and GIP. Elevated incretin levels increase glucose‑dependent insulin secretion from pancreatic β‑cells and suppress glucagon release from α‑cells, thereby reducing both fasting and post‑prandial blood glucose concentrations.

Common Side Effects

• Nasopharyngitis: mild inflammation of the nasal passages and throat.
• Headache: transient pain in the head region.
• Upper respiratory tract infection: symptoms of cough, sore throat, or congestion.
• Gastrointestinal upset: includes nausea, diarrhea, or abdominal discomfort.
• Dizziness: sensation of light‑headedness or unsteadiness.

Serious or Rare Side Effects

• Pancreatitis: severe abdominal pain requiring immediate medical attention.
• Severe allergic reactions: including rash, angioedema, or anaphylaxis.
• Joint pain: unexplained arthralgia that may be disabling.
• Hypoglycaemia (when combined with insulin or sulfonylureas): low blood sugar episodes.
• Hepatic injury: abnormal liver function tests or hepatitis.

Before initiating therapy, clinicians should consider the following precautions:

• Renal function: assess baseline kidney function and adjust dose if necessary.
• Hepatic impairment: use with caution in patients with liver disease.
• Hypersensitivity: discontinue if signs of allergic reaction appear.
• Pregnancy and lactation: evaluate risk‑benefit ratio before prescribing.
• Drug interactions: review concomitant medications for potential interactions.
• Store at ambient temperature: keep in the original packaging, protect from moisture and light.

Sitagliptin may interact with several co‑administered drugs.

Major Interactions (Avoid)

• Insulin: concurrent use can increase the risk of hypoglycaemia.
• Sulfonylureas (e.g., glipizide): may potentiate low blood glucose.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): can raise sitagliptin plasma levels.

Moderate Interactions (Monitor Closely)

• ACE inhibitors: monitor renal function and blood pressure.
• Diuretics: watch for electrolyte disturbances.
• Rifampin: may reduce sitagliptin exposure, decreasing efficacy.