Cambodia Pharmacy Exit Exam cheat sheet

Bioavailability (F) = (AUC_oral × D_IV) / (AUC_IV × D_oral); absolute F compares extravascular to IV dose, relative F compares two non-IV products.

Noyes–Whitney dissolution rate: dC/dt = (D·A/h)·(Cs − C), so rate rises with surface area A and saturation solubility Cs, and falls with diffusion layer thickness h.

First-order drug degradation: C = C0·e^(−kt), t90 (time to 90% label claim) = 0.105/k; zero-order (suspensions, some solid dispersions) gives t90 = 0.1·C0/k0.

Arrhenius relation k = A·e^(−Ea/RT); a 10 °C rise typically increases degradation 2–4 fold, the basis of accelerated stability testing.

ICH accelerated conditions: 25 °C/60% RH or 30 °C/65% RH for 6 months with long-term data at 12 months minimum; Zone IVb (hot/humid, relevant to Cambodia) uses 30 °C/75% RH.

Tablet hardness, friability (<1% weight loss), disintegration time and content uniformity are the core pharmacopoeial QC tests for compressed tablets.

Sterile products: terminal sterilization by moist heat 121 °C/15 min (F0 ≥ 8 min); aseptic filling requires Grade A/B cleanroom with HEPA-filtered unidirectional airflow.

Suspension stability is governed by Stokes' law v = d²(ρp − ρl)g/18η; reducing particle diameter and increasing vehicle viscosity slow sedimentation.

Beer–Lambert law A = ε·b·c underlies UV-Vis quantitation; linear range is typically 0.2–0.8 absorbance units.

HPLC retention factor k = (tR − t0)/t0; resolution Rs = 2(tR2 − tR1)/(w1 + w2), and Rs ≥ 1.5 indicates baseline separation.

Acid–base extraction exploits pKa: an amine salt is water-soluble at pH < pKa and extracted into organic solvent at pH > pKa + 2.

ICH Q2 validation parameters: accuracy, precision (repeatability, intermediate), specificity, LOD/LOQ, linearity, range and robustness.

LOD = 3.3σ/S and LOQ = 10σ/S, where σ is the standard deviation of the response and S the slope of the calibration curve.

Prodrug design examples: enalapril → enalaprilat, sulfasalazine → 5-aminosalicylate in colon, and ester prodrugs to mask carboxylate polarity.

Structure–activity principles: log P (Lipinski's rule of 5: MW ≤ 500, log P ≤ 5, H-bond donors ≤ 5, acceptors ≤ 10) predicts oral absorption.

Titrimetric assay of a weak base uses non-aqueous titration with perchloric acid in glacial acetic acid, with crystal violet indicator.

Primary plant metabolites (carbohydrates, amino acids, lipids) support growth; secondary metabolites (alkaloids, terpenoids, phenolics, glycosides) carry pharmacological activity.

Alkaloids are basic nitrogen-containing compounds; extraction uses acidified water then basification with organic solvent (e.g., morphine from opium, quinine from Cinchona bark).

Cardiac glycosides (digoxin from Digitalis lanata) inhibit Na+/K+-ATPase; the aglycone determines activity and the sugar moiety governs pharmacokinetics.

Artemisinin from Artemisia annua is a sesquiterpene lactone with an endoperoxide bridge essential for antimalarial activity; semisynthetic derivatives include artesunate and artemether.

Standardization of herbal material requires macroscopic/microscopic identity, chromatographic fingerprint (TLC/HPLC), assay of marker compound, and limits for heavy metals, aflatoxins and microbial load.

Cambodia's medicinal flora includes Brucea javanica, Eurycoma longifolia, Andrographis paniculata and Alpinia species; WHO monographs and national traditional medicine lists govern claims.

Extraction methods ranked by efficiency: maceration < percolation < Soxhlet; supercritical CO2 suits thermolabile lipophilic compounds.

Phytochemical screening tests: Dragendorff (alkaloids), Molisch (carbohydrates), Fehling (reducing sugars), Liebermann–Burchard (steroids/triterpenes), foam test (saponins).

Receptor occupancy follows the Hill equation E = Emax·C^n/(EC50^n + C^n); n > 1 indicates positive cooperativity and a steeper concentration–response curve.

Competitive antagonists shift the dose–response curve rightward without lowering Emax; non-competitive antagonists reduce Emax.

First-order elimination half-life t1/2 = 0.693·Vd/CL; steady state is reached in about 4–5 half-lives, and loading dose = Vd × target concentration / F.

Cytochrome P450 interactions: inhibitors (ketoconazole, ritonavir, erythromycin) raise substrate levels; inducers (rifampicin, carbamazepine, efavirenz) lower them.

Therapeutic index = TD50/ED50; narrow-index drugs (digoxin, warfarin, lithium, phenytoin, aminoglycosides) require therapeutic drug monitoring.

Beta-lactam mechanism is inhibition of transpeptidase (cell wall synthesis); aminoglycosides bind the 30S ribosomal subunit, macrolides the 50S.

Antimalarial therapy in Cambodia uses artemisinin-based combination therapy (e.g., artesunate–mefloquine or DHA–piperaquine) for Plasmodium falciparum, with primaquine for vivax hypnozoites after G6PD testing.

Opioid analgesia acts on mu receptors; naloxone is a competitive antagonist used for reversal, and respiratory depression is the key toxicity.

Pharmaceutical care process: assessment (subjective/objective data), medication-related problem identification, care plan, monitoring and documentation (SOAP format).

Adverse drug reaction classification: Type A (dose-related, predictable, e.g., bleeding with warfarin), Type B (idiosyncratic, e.g., anaphylaxis), Type C (chronic), Type D (delayed), Type E (withdrawal).

Naranjo scale (score ≥ 9 definite, 5–8 probable, 1–4 possible, ≤ 0 doubtful) and WHO-UMC causality categories structure ADR assessment.

Causality vs preventability: use Naranjo or WHO-UMC for causality and the Schumock–Thornton criteria for preventability of ADRs.

Renal dose adjustment uses Cockcroft–Gault CrCl = (140 − age) × weight / (72 × SCr), multiplied by 0.85 for females.

Therapeutic drug monitoring indications: narrow therapeutic index, poor correlation of dose to effect, and defined target range; sample timing depends on half-life (trough before next dose).

Medication reconciliation at admission, transfer and discharge reduces unintentional discrepancies; high-risk groups are elderly, polypharmacy (≥5 drugs) and renal impairment.

Antimicrobial stewardship core actions: right drug, dose, route and duration; de-escalation based on culture; prospective audit and feedback.

A legally valid prescription requires prescriber identity and signature, patient name, drug name, strength, dosage form, quantity, directions and date; controlled substances add specific requirements.

Label elements: patient name, drug and strength, directions, quantity, date of dispensing, pharmacy identity, prescriber, and special warnings (e.g., 'for external use only', 'keep out of reach of children').

The 'five rights' of dispensing: right patient, right drug, right dose, right route, right time; counselling adds right documentation and right to refuse.

Auxiliary labels communicate storage (e.g., refrigerate 2–8 °C), administration (with food, shake well) and interaction warnings in the patient's language.

Hospital pharmacy dispensing systems: unit dose, floor stock, and automated dispensing cabinets; each requires documented stock reconciliation and expiry checks.

Extemporaneous compounding requires a master formula record, beyond-use date assignment, and documented calculation double-check by a second person.

Look-alike/sound-alike (LASA) drug pairs (e.g., Losec/Lasix, hydrOXYzine/hydrALAZINE) require tall-man lettering and physical separation on shelves.

Prescription handling steps: receipt and legality check, interpretation, screening for interactions and allergies, preparation, labeling, double-check, and counselling with documentation.

Cambodia's Law on Drug Management (2007) governs drug registration, import/export, licensing, advertising and inspection, administered by the Ministry of Health's Department of Drugs and Food.

Drug classification in Cambodia distinguishes prescription ('Rx') medicines from over-the-counter products; narcotics and psychotropics require special import and dispensing authorization.

A pharmacy premises licence and a pharmacist practice licence are separate; the pharmacist-in-charge must be physically present for the pharmacy to operate.

Controlled substances follow scheduling analogous to UN conventions (single convention 1961, psychotropics 1971); records of receipt, dispensing and stock must be retained and reconciled.

Prohibited acts include dispensing counterfeit, substandard, expired or unregistered drugs, and advertising prescription drugs to the public.

Professional ethics: confidentiality of patient information, informed consent, avoidance of conflicts of interest, and refusal to dispense without referral when safety requires it.

Good Pharmacy Practice (WHO/FIP) covers premises, personnel, equipment, documentation, and patient counselling standards.

Pharmacovigilance obligations: reporting serious adverse drug reactions to the national centre within defined timelines and maintaining dispensing records for inspection.

Inventory control: reorder point = (average daily demand × lead time) + safety stock; economic order quantity EOQ = √(2DS/H) where D is annual demand, S ordering cost, H holding cost per unit.

ABC analysis classifies stock by value (A items ~20% of items, ~80% of expenditure); VEN analysis classifies by clinical criticality (Vital, Essential, Non-essential).

Stock turnover ratio = cost of goods sold / average inventory value; a low ratio signals overstock and expiry risk.

Procurement principles: transparent tender, prequalification of suppliers, quantification based on morbidity or consumption data, and quality assurance before acceptance.

Cost-minimization, cost-effectiveness (cost per life-year or per case averted), cost-utility (cost per QALY) and cost-benefit (net monetary gain) are the four pharmacoeconomic evaluations.

Incremental cost-effectiveness ratio ICER = (C1 − C0)/(E1 − E0); compare with a willingness-to-pay threshold to judge value.

Drug supply chain in Cambodia runs from central medical stores through provincial and operational district warehouses to health centres and hospitals; stock-outs are tracked via LMIS reports.

Mark-up, dispensing fee and reference pricing are the main mechanisms used to control medicine prices for patients.

Incidence = new cases / population at risk per time period; prevalence = all existing cases / total population at a point or period; prevalence ≈ incidence × duration for stable disease.

Attack rate, case fatality rate (deaths/cases × 100) and mortality rate (deaths/population × 100,000) measure different aspects of disease burden.

Sensitivity = TP/(TP + FN); specificity = TN/(TN + FP); positive predictive value depends on prevalence: PPV = (Se × P)/(Se × P + (1 − Sp)(1 − P)).

Herd immunity threshold = 1 − 1/R0; for measles (R0 12–18) this exceeds 90%, requiring very high coverage.

Cambodia's priority national programmes include immunization (EPI), TB DOTS, HIV/AIDS, malaria, dengue surveillance and maternal-child health.

Health promotion uses the Ottawa Charter actions: build healthy public policy, create supportive environments, strengthen community action, develop personal skills, reorient health services.

Screening programme criteria (Wilson–Jungner) include an important health problem, accepted test, early detection benefit and cost-effectiveness.

Epidemiological study designs ranked by evidence strength for causation: ecological, cross-sectional, case-control, cohort, randomized controlled trial, systematic review/meta-analysis.

Randomization, control group, blinding and sample size calculation are the four pillars of a valid clinical trial; allocation concealment prevents selection bias.

Sample size for two means: n per group = 2(zα/2 + zβ)²σ²/Δ²; for proportions n = (zα/2 + zβ)²·[p1(1−p1) + p2(1−p2)]/Δ².

Type I error (α) is rejecting a true null hypothesis; type II error (β) is failing to reject a false null; power = 1 − β, conventionally 80%.

Parametric tests assume normality and equal variance: t-test for two means, ANOVA for ≥3 groups; non-parametric alternatives are Mann–Whitney U and Kruskal–Wallis.

Relative risk = [a/(a+b)]/[c/(c+d)] in cohort studies; odds ratio = ad/bc in case-control studies; OR approximates RR only when disease is rare (<10%).

95% confidence interval for a mean = x̄ ± 1.96·(s/√n); a CI excluding the null value corresponds to p < 0.05.

Intention-to-treat analysis preserves randomization and avoids attrition bias; per-protocol analysis estimates efficacy but can be biased.

Critical appraisal of a paper checks design, sample size and power, bias control, statistical appropriateness, generalizability and conflicts of interest.

Placeholder section retained only if a domain is duplicated; use domain 10 for all biostatistics content.

A p-value is the probability of observing data at least as extreme as obtained, given that the null hypothesis is true; it is not the probability the null is true.

Correlation coefficient r ranges −1 to 1 and measures linear association only; r² gives the proportion of variance explained in regression.

Number needed to treat NNT = 1/absolute risk reduction; number needed to harm NNH = 1/absolute risk increase.

Meta-analysis pools effect sizes with fixed-effect or random-effects models; heterogeneity is quantified by I² (>50% suggests substantial heterogeneity).

Observational designs: cross-sectional (prevalence), case-control (odds ratio, rare outcomes), cohort (incidence, relative risk, temporality).

Bias types: selection, information/measurement, recall, confounding, publication bias; confounding is addressed by randomization, restriction, matching or multivariable adjustment.

Descriptive statistics: mean and SD for symmetric data; median and interquartile range for skewed data; a skewed distribution has mean pulled toward the tail.

Placeholder section retained only if a domain is duplicated; use domain 4 for all pharmacology content.

Antihypertensive first-line classes: ACE inhibitors/ARBs, calcium channel blockers, thiazides and beta-blockers; choice depends on comorbidity (e.g., ACEi in diabetes with proteinuria).

Asthma stepwise therapy: inhaled corticosteroid as controller; short-acting beta-2 agonist as reliever; long-acting beta-2 agonist added only with ICS.

Diabetes pharmacotherapy: metformin first line for type 2; insulin required in type 1 and in pregnancy when oral agents are insufficient.

Warfarin monitoring uses INR with target 2.0–3.0 for most indications and 2.5–3.5 for mechanical mitral valves.

Antituberculosis regimen: 2 months HRZE intensive phase followed by 4 months HRE continuation for drug-susceptible TB, with adherence support (DOTS).

NSAID adverse effects: GI ulceration, renal impairment and increased cardiovascular risk; gastroprotection with a proton pump inhibitor is indicated in high-risk patients.

Corticosteroid long-term adverse effects: osteoporosis, hyperglycaemia, hypertension, infection, cataract and adrenal suppression on abrupt withdrawal.