1. Sitagliptin Phosphate

7. Pharmacokinetics (Absorption, Distribution, Metabolism, Excretion): Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.

16a. Renal Considerations: Renal: Strictly renal-function dependent (~79% excreted unchanged in urine)! Must reduce dose to 50 mg OD for eGFR 30–44 mL/min and 25 mg OD for eGFR <30 mL/min. Hepatic: No dose adjustment needed in mild-to-moderate hepatic impairment (Child-Pugh A/B).

16b. Hepatic Considerations: Renal: Strictly renal-function dependent (~79% excreted unchanged in urine)! Must reduce dose to 50 mg OD for eGFR 30–44 mL/min and 25 mg OD for eGFR <30 mL/min. Hepatic: No dose adjustment needed in mild-to-moderate hepatic impairment (Child-Pugh A/B).

• Nasopharyngitis, upper respiratory tract symptoms, headache, mild GI discomfort; weight-neutral and very low intrinsic risk of hypoglycaemia unless combined with a sulfonylurea or insulin.
• Acute pancreatitis (persistent, severe mid-epigastric abdominal pain radiating to the back with vomiting), bullous pemphigoid (blistering skin lesions in elderly), severe disabling polyarthralgia (joint pain), angioedema (especially when co-administered with ACE inhibitors).

• Slightly increases plasma digoxin levels (monitor in narrow therapeutic index patients)
• When added to a sulfonylurea (glimepiride/gliclazide) or insulin, a dose reduction of the secretagogue/insulin is often needed to prevent hypoglycaemia

15. Use in Special Populations (Pregnancy, Lactation, Paediatrics, Geriatrics): Evaluate maternal-foetal benefit-risk ratio, paediatric mg/kg ceiling, and geriatric renal function prior to prescribing.

17. Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

• Patient Counselling Checklist: Explain that sitagliptin works intelligently in a glucose-dependent manner—stimulating insulin release only when blood sugar rises after meals, so it rarely causes low blood sugar or weight gain by itself. Instruct the patient to stop the drug and seek urgent medical care if severe, persistent stomach pain radiating to the back occurs.
• Meal & Clock Timing Instruction: With or without food (if in FDC with metformin, take WITH meals). (Once daily in the morning (or twice daily with breakfast and dinner if FDC).)
• Missed Dose Protocol: Take as soon as remembered on the same day; if close to the next day's dose, skip. Never double the dose.
• Geriatric Dispensing Pearl: Excellent safety profile in elderly CGHS patients (no orthostasis, weight gain, or intrinsic hypoglycaemia). Audit the prescription carefully to ensure the patient is not taking both a generic Sitagliptin tablet from the CGHS counter and a branded Vildagliptin/Teneligliptin FDC from a private prescription.

Storage & Dispensing Notes: COLD CHAIN MANDATORY (2°C–8°C): Store in a pharmaceutical refrigerator between 2°C and 8°C; DO NOT FREEZE. Protect from light and heat during dispensing.