Semester 7
BP703T
Drug Store Management, Investigational Drugs & Clinical Laboratory Tests
This unit covers three practical areas. Drug Store Management — organization, types of materials, storage conditions, purchase procedures, inventory control techniques (EOQ, reorder level, ABC/VED analysis). Investigational Use of Drugs — principles, classification, control, and the pharmacist’s role in clinical trials. Interpretation of Clinical Laboratory Tests — understanding blood chemistry (glucose, creatinine, BUN, electrolytes), hematology (CBC, Hb, WBC), and urinalysis (routine and microscopic).
Syllabus & Topics
- 1Drug Store Organization: Drug store (pharmacy store/central drug store): facility within hospital for receiving, storing, and distributing pharmaceutical products. Organization: Chief Pharmacist/Store Manager → Store Pharmacists → Store Keepers → Helpers. Types of materials stocked: (1) Drugs and medicines (tablets, capsules, injectables, syrups, ointments). (2) Surgical supplies (sutures, dressings, gloves, catheters). (3) Biologicals (vaccines, sera — cold chain storage). (4) Diagnostic agents (contrast media, reagents). (5) Disinfectants and antiseptics. (6) IV fluids (NS, RL, D5W). (7) Controlled substances (narcotics, psychotropics — separate locked storage). Storage conditions: (1) General: 15-25°C (controlled room temperature), dry, clean, well-ventilated, pest-free. (2) Cold storage: 2-8°C (refrigerator) — insulins, vaccines, some antibiotics. (3) Freezer: -20°C — some biologicals, certain reagents. (4) Light-sensitive: amber containers, dark storage. (5) Flammable: separate fireproof area (ether, alcohol). (6) Controlled drugs: double-locked safe/cupboard.
- 2Purchase & Procurement: Purchase procedure: (1) Identification of need: based on consumption data, formulary requirements, new additions. (2) Purchase requisition: department raises requisition to purchase department. (3) Supplier selection: approved vendor list, tender/quotation process. Public hospitals: government e-procurement/GeM (Government e-Marketplace). Private: direct purchase or rate contract. (4) Purchase order (PO): formal document sent to vendor — drug name, quantity, specifications, price, delivery date, payment terms. (5) Receiving: goods received → checked against PO and delivery challan → quality inspection → QC testing (if required) → accepted or rejected. (6) Documentation: GRN (Goods Received Note), bin card entry, computerized inventory update. Procurement methods: (1) Open tender: public advertisement, lowest qualified bidder. (2) Limited tender: invitation to pre-qualified vendors. (3) Rate contract: pre-negotiated rates for a fixed period (6-12 months) — most efficient for hospitals. (4) Emergency purchase: for urgent requirements — bypasses normal procedure with authorization.
- 3Inventory Control – Principles: Inventory control: scientific system of managing stock to ensure continuous availability of drugs while minimizing holding costs and preventing stockouts. Objectives: (1) Ensure uninterrupted supply. (2) Minimize inventory investment. (3) Minimize losses (expiry, damage, pilferage). (4) Maintain optimal stock levels. Key concepts: (1) Lead time: time between placing order and receiving goods (typically 7-30 days). (2) Safety stock (buffer stock): minimum stock maintained to prevent stockout during unexpected demand or delayed delivery. Safety stock = average daily consumption × maximum lead time deviation. (3) Reorder level (ROL): stock level at which a new order should be placed. ROL = (average daily consumption × lead time) + safety stock. When stock reaches ROL → trigger purchase order. (4) Maximum stock level: upper limit of inventory. Max level = ROL + EOQ − (min consumption × min lead time). (5) Minimum stock level: ROL − (average consumption × average lead time). Should not fall below safety stock.
- 4Economic Order Quantity (EOQ): EOQ: the optimal order quantity that minimizes TOTAL inventory costs (sum of ordering costs and carrying costs). EOQ formula: Q* = √(2DS/H). Where: D = annual demand (units/year). S = ordering cost per order (₹/order — includes processing, delivery, inspection). H = annual holding/carrying cost per unit (₹/unit/year — includes storage, insurance, obsolescence, capital cost). Example: Drug X: D = 10,000 tablets/year, S = ₹500/order, H = ₹10/tablet/year. EOQ = √(2 × 10,000 × 500 / 10) = √1,000,000 = 1,000 tablets per order. Number of orders/year = 10,000/1,000 = 10 orders. Assumptions: demand is constant and known, lead time is constant, no quantity discounts, no stockouts allowed. Limitations: real-world demand fluctuates, discounts available for larger orders, storage capacity constraints.
- 5ABC & VED Analysis: Methods for analyzing drug expenditure: (1) ABC Analysis (Always Better Control / Pareto Analysis): classifies drugs based on COST/VALUE of consumption. Category A: 10-20% of items → 70-80% of expenditure (vital few — tight control, frequent ordering, accurate demand forecasting). Category B: 20-30% of items → 15-20% of expenditure (moderate control). Category C: 50-70% of items → 5-10% of expenditure (trivial many — simple control, bulk ordering). Application: focus management attention on Category A items → maximum cost savings. (2) VED Analysis (Vital, Essential, Desirable): classifies based on CRITICALITY for patient care. Vital (V): drugs whose shortage is LIFE-THREATENING — cannot be substituted. Anti-venoms, emergency drugs, insulin, antiretrovirals. Essential (E): drugs whose shortage causes significant patient discomfort but not life-threatening. Can be substituted. Most prescription drugs. Desirable (D): drugs whose shortage causes inconvenience but alternatives readily available. Vitamins, cough syrups. Combined ABC-VED matrix: most useful — AV items (high cost + vital) = highest priority. DC items (low cost + desirable) = lowest priority.
- 6Investigational Use of Drugs: Investigational drugs: drugs being evaluated in clinical trials for safety, efficacy, or new indications — NOT YET approved for marketing (or approved drugs being tested for new uses). Principles: (1) Patient safety paramount. (2) Informed consent mandatory. (3) IRB/IEC approval required. (4) Compliance with GCP guidelines. (5) Proper documentation and accountability. Classification: (1) Phase I-III investigational drugs (pre-approval). (2) Compassionate use/expanded access (for seriously ill patients when no alternative available). (3) Off-label use investigation. Control: (1) Separate storage from approved drugs (clearly labeled ‘FOR INVESTIGATIONAL USE ONLY’). (2) Dispensed only to enrolled patients per protocol. (3) Strict accountability log (received, dispensed, returned, destroyed). (4) Temperature monitoring (stability). (5) Blinding maintained (if applicable). Hospital pharmacist’s role: (1) Receive, store, and dispense investigational drugs. (2) Maintain drug accountability records. (3) Ensure proper labeling and blinding. (4) Advisory committee membership (IRB/IEC). (5) Counsel patients on investigational drug use. (6) Report protocol deviations.
- 7Clinical Lab Tests – Blood Chemistry: Clinical pharmacist interprets lab tests to monitor drug therapy and detect drug-induced changes. Blood chemistry (normal values): (1) Blood glucose: Fasting: 70-110 mg/dL. Post-prandial: <140 mg/dL. HbA1c: <7% (diabetics). Relevance: monitoring antidiabetic therapy, drug-induced hyperglycemia (corticosteroids, thiazides). (2) Serum creatinine: 0.6-1.2 mg/dL (male), 0.5-1.1 mg/dL (female). Elevated: kidney damage — dose adjustment needed for renally cleared drugs. (3) BUN (Blood Urea Nitrogen): 7-20 mg/dL. Elevated: renal dysfunction, dehydration, upper GI bleeding. (4) Electrolytes: Na⁺: 135-145 mEq/L (hyponatremia: SIADH, diuretics. Hypernatremia: dehydration). K⁺: 3.5-5.0 mEq/L (hypokalemia: loop diuretics, amphotericin B. Hyperkalemia: ACE inhibitors, K⁺-sparing diuretics — DANGEROUS: cardiac arrhythmias). (5) Liver function: ALT: 7-56 U/L, AST: 10-40 U/L. Elevated: hepatotoxicity (paracetamol overdose, isoniazid, statins). Bilirubin: 0.1-1.0 mg/dL. Albumin: 3.5-5.0 g/dL.
- 8Clinical Lab Tests – Hematology & Urinalysis: Hematology (CBC — Complete Blood Count): (1) Hemoglobin: Male: 14-18 g/dL, Female: 12-16 g/dL. Low: anemia (iron deficiency, B12 deficiency, drug-induced — methotrexate, chloramphenicol). (2) RBC: Male: 4.5-5.5 × 10⁶/μL, Female: 4.0-5.0 × 10⁶/μL. (3) WBC: 4,000-11,000/μL. Elevated (leukocytosis): infection, inflammation, corticosteroid therapy. Decreased (leukopenia/neutropenia): drug-induced — clozapine, carbamazepine, methotrexate, chemotherapy → agranulocytosis risk → LIFE-THREATENING. Differential: Neutrophils 40-70%, Lymphocytes 20-40%, Monocytes 2-8%, Eosinophils 1-4%, Basophils 0-1%. (4) Platelets: 150,000-400,000/μL. Low (thrombocytopenia): heparin-induced thrombocytopenia (HIT), chemotherapy, valproic acid. (5) ESR: Male <15 mm/hr, Female <20 mm/hr — inflammation marker. Urinalysis: (1) Color: pale yellow (normal). Dark: dehydration, bilirubin. Red: blood, rifampicin. (2) pH: 4.5-8.0 (normally ~6). (3) Specific gravity: 1.005-1.030. (4) Glucose: absent normally. Present: diabetes (glycosuria). (5) Protein: absent normally. Present: kidney disease (proteinuria). (6) Ketones: absent. Present: diabetic ketoacidosis, starvation. (7) Microscopy: RBCs, WBCs, casts, crystals.
Learning Objectives
EOQ Calculation: Derive and apply the EOQ formula with a numerical example.
ABC-VED Matrix: Explain ABC and VED analysis and how the combined matrix is used for inventory prioritization.
Reorder Level: Define reorder level, safety stock, and lead time and calculate ROL given consumption data.
Investigational Drugs: Describe the hospital pharmacist’s role in handling investigational drugs.
Lab Values: List normal values for 10 common clinical lab tests and their drug therapy relevance.
Exam Prep Questions
Q1. How do you calculate Economic Order Quantity?
EOQ = √(2DS/H). D = annual demand, S = cost per order, H = holding cost per unit per year. Example: If a hospital uses 12,000 units of Drug A per year, each order costs ₹600 to process, and holding cost is ₹5/unit/year: EOQ = √(2 × 12,000 × 600 / 5) = √2,880,000 = 1,697 units per order. This means: order ~1,700 units each time, place ~7 orders per year (12,000 ÷ 1,700). This MINIMIZES total cost (ordering costs go down as you order more, but storage costs go up — EOQ balances both).
Q2. Why is serum creatinine important for pharmacists?
Serum creatinine reflects KIDNEY FUNCTION — elevated creatinine indicates impaired renal clearance. Many drugs are eliminated by kidneys: aminoglycosides, vancomycin, digoxin, lithium, metformin, ACE inhibitors, allopurinol. If kidneys are impaired (high creatinine), these drugs ACCUMULATE → toxicity. The pharmacist uses the Cockcroft-Gault equation to estimate CrCl from serum creatinine: CrCl = [(140 – age) × weight] / (72 × SCr) × 0.85 for females. Based on CrCl, dose is reduced or interval is extended. Without this monitoring, serious toxicity can occur (aminoglycoside nephro/ototoxicity, digoxin toxicity, lithium toxicity).
Q3. What is the ABC-VED matrix and how does it help?
The ABC-VED matrix combines cost-based (ABC) and criticality-based (VED) classifications into a 3×3 grid.
Category I (Highest priority): AV, AE, BV — expensive AND/OR vital drugs. Tight control, never allow stockout, accurate forecasting, frequent review.
Category II (Moderate): AD, BE, CV — moderate priority. Regular monitoring.
Category III (Lowest priority): BD, CE, CD, DE — inexpensive AND non-critical. Simple controls, bulk ordering.
This combined approach prevents the mistake of ABC analysis alone — which might understock a CHEAP but VITAL drug (like adrenaline — Category C by cost but V by criticality → CV = Category I priority).