DHA Pharmacist Exam cheat sheet

Beta-1 selective blockers (metoprolol, atenolol, bisoprolol) lower heart rate and renin release with less bronchospasm than non-selective agents.

ACE inhibitors reduce angiotensin II and aldosterone, causing hyperkalemia and a dry cough from bradykinin accumulation; they are contraindicated in pregnancy.

Warfarin inhibits vitamin K epoxide reductase, lowering factors II, VII, IX and X; effect is monitored by INR and reversed with vitamin K.

Unfractionated heparin potentiates antithrombin III, is monitored by aPTT, and is reversed by protamine sulfate.

Aminoglycosides exhibit concentration-dependent killing and a post-antibiotic effect; nephrotoxicity and ototoxicity require serum level monitoring.

Phenytoin follows saturable (zero-order) metabolism at higher doses, so a small dose increase can produce disproportionate toxicity.

Statins inhibit HMG-CoA reductase; myopathy risk rises with CYP3A4 inhibitors (macrolides, azole antifungals) and with gemfibrozil.

Metformin reduces hepatic gluconeogenesis and is first-line for type 2 diabetes; withhold before iodinated contrast when renal function is impaired to avoid lactic acidosis.

Digoxin inhibits Na+/K+-ATPase and has a narrow therapeutic index; hypokalemia, hypomagnesemia and hypercalcemia potentiate toxicity.

Cockcroft-Gault: CrCl (mL/min) = [(140 − age) × weight in kg] ÷ (72 × serum creatinine in mg/dL); multiply by 0.85 for women.

Ideal body weight = 50 kg + 2.3 kg per inch over 5 feet (male) or 45.5 kg + 2.3 kg per inch over 5 feet (female).

Mosteller body surface area: BSA (m²) = square root of [(height in cm × weight in kg) ÷ 3600].

ISMP high-alert classes include insulin, anticoagulants, opioids, concentrated electrolytes, neuromuscular blockers, chemotherapy and parenteral nutrition.

Look-alike/sound-alike pairs are managed with tall-man lettering, physically separate storage and read-back verification.

Proportion of days covered of 80% or greater is the conventional threshold for adequate adherence in pharmacy quality metrics.

Medication reconciliation compares the best possible medication history with active orders at admission, transfer and discharge.

The core 5 rights are right patient, drug, dose, route and time; extended rights add documentation and indication.

Medication error categories are prescribing, transcribing, dispensing, administration and monitoring; reporting systems are non-punitive.

Absolute bioavailability: F = (AUC oral ÷ AUC intravenous) × (dose intravenous ÷ dose oral); the intravenous reference equals 1.

t½ = 0.693 ÷ k; Vd = dose ÷ C0; CL = k × Vd; steady state is approached after roughly 4 to 5 half-lives.

Noyes-Whitney: dissolution rate is proportional to surface area and solubility and inversely proportional to diffusion layer thickness; micronization and salt formation increase dissolution.

Zero-order release delivers a constant amount per unit time (osmotic pump, reservoir); first-order release rate is proportional to the amount remaining.

Higuchi model Q = k√t describes diffusion-controlled release from a matrix system.

BCS Class I = high solubility/high permeability; Class II = low solubility/high permeability; Class III = high solubility/low permeability; Class IV = both low.

Bioequivalence requires the 90% confidence interval of the geometric mean ratios for AUC and Cmax to fall within 80% to 125%.

Excipient roles: binder (povidone), disintegrant (croscarmellose), lubricant (magnesium stearate), glidant (colloidal silicon dioxide).

Lyophilization stages are freezing, primary drying (sublimation of ice) and secondary drying (desorption of bound water).

Henderson-Hasselbalch: pH = pKa + log([unprotonated] ÷ [protonated]); weak acids ionize progressively as pH rises above the pKa.

Penicillins share the 6-aminopenicillanic acid nucleus; cephalosporins are built on 7-aminocephalosporanic acid.

Prodrugs: enalapril to enalaprilat, codeine to morphine (CYP2D6), clopidogrel to its active thiol metabolite (CYP2C19).

Lipinski rule of five: molecular weight 500 or less, logP 5 or less, hydrogen bond donors 5 or less, acceptors 10 or less.

For weak-acid drugs solubility increases with rising pH; for weak bases solubility increases as pH falls.

Common degradation pathways are hydrolysis of esters and amides, oxidation accelerated by oxygen, light and metals, and photolysis.

Plant sources: morphine and quinine (alkaloids), digoxin (Digitalis lanata), vincristine (Catharanthus roseus), paclitaxel (Taxus brevifolia).

The S-enantiomer of ibuprofen carries most COX-inhibitory activity, illustrating that enantiomers can differ in potency and kinetics.

Gram-positive organisms have thick peptidoglycan and no outer membrane; Gram-negative organisms have thin peptidoglycan plus an outer membrane containing lipopolysaccharide.

MIC is the lowest concentration inhibiting visible growth; MBC is the lowest concentration killing at least 99.9% of the inoculum.

MRSA resistance is mediated by the mecA gene encoding PBP2a, a penicillin-binding protein with low affinity for beta-lactams.

Extended-spectrum beta-lactamases hydrolyse penicillins and cephalosporins but are inhibited by clavulanate; carbapenems generally remain stable.

On MacConkey agar lactose fermenters such as E. coli form pink colonies, while non-fermenters remain colourless.

Autoclave standard: 121 °C at 15 psi for 15 minutes, verified with Geobacillus stearothermophilus spores; dry heat is 160 °C for 2 hours.

Clostridioides difficile spores survive alcohol; use soap and water handwashing plus chlorine-based environmental disinfection.

70% ethanol is more bactericidal than 95% because water is required for protein denaturation.

USP <797> requires an ISO Class 5 direct compounding area within an ISO Class 7 buffer room for low- and medium-risk compounded sterile preparations.

Hazardous drugs under USP <800> require negative-pressure containment, an externally vented Class II biological safety cabinet, closed-system transfer devices and PPE.

A 0.22 micrometre membrane filter sterilizes heat-labile solutions but does not remove endotoxin; depyrogenation uses dry heat at 250 °C.

Steam sterilization is validated to F0 of at least 12 minutes at 121 °C; terminal sterilization is preferred over aseptic processing when the product tolerates it.

Spaulding classification: critical items require sterilization, semicritical items high-level disinfection, noncritical items low-level disinfection.

WHO 5 moments for hand hygiene: before patient contact, before an aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Beyond-use dates for compounded sterile preparations depend on risk level, storage temperature and sterility testing, and must be stated on the label.

The anteroom separates uncontrolled space from the buffer room and is maintained at ISO Class 8 or better.

The Dubai Health Authority licenses health facilities and professionals in Dubai, while federal MOHAP registers medicines and controls narcotic substances.

A valid prescription states patient name, date, drug name, strength, dosage form, quantity, directions, and prescriber signature and licence number.

Prescription-only medicines may not be advertised to the public; direct-to-consumer promotion of prescription drugs is prohibited.

The four ethical principles are autonomy, beneficence, nonmaleficence and justice; informed consent requires capacity, disclosure, understanding and voluntariness.

Confidentiality may be breached only where law mandates reporting or with patient consent.

Suspected serious adverse drug reactions must be reported to the national pharmacovigilance authority; marketing authorization holders have mandatory reporting duties.

Dispensing errors are documented and disclosed to the patient and prescriber under open-disclosure principles.

Prescription and controlled-drug transaction records must be retained for the period set by local regulation and produced on inspection.

Primary literature is original research; secondary literature indexes and abstracts it (PubMed, Embase); tertiary literature summarizes it (textbooks, compendia).

The PICO framework structures a question as Population, Intervention, Comparator and Outcome.

Systematic reviews with meta-analysis rank near the top of the evidence hierarchy; unsystematic case reports rank near the bottom.

Micromedex, Lexicomp, AHFS Drug Information, Martindale and the BNF are tertiary drug information sources.

Causality assessment of adverse drug reactions uses the Naranjo scale or WHO-UMC categories (certain, probable, possible, unlikely).

A systematic response to a drug information request involves clarifying the question, searching, evaluating, formulating, documenting and following up.

Off-label use should be supported by peer-reviewed evidence and documented in the record; manufacturers may not promote off-label indications.

Pregnancy and lactation queries are answered with LactMed, ReproTox or TERIS; the former US pregnancy risk categories have been replaced by PLLR narrative labelling.

Sensitivity = TP ÷ (TP + FN); specificity = TN ÷ (TN + FP); predictive values depend on disease prevalence in the population.

Absolute risk reduction = control event rate − treatment event rate; NNT = 1 ÷ ARR and NNH = 1 ÷ absolute risk increase.

Relative risk = risk in exposed ÷ risk in unexposed; the odds ratio approximates relative risk when the outcome is rare (under about 10%).

Type I error (alpha) is rejecting a true null hypothesis; type II error (beta) is failing to reject a false null; power = 1 − beta.

A 95% confidence interval that excludes the null value corresponds to p < 0.05 for a two-sided test.

Intention-to-treat analysis includes all randomized participants in their assigned groups and protects against attrition bias.

Parametric tests (t-test, ANOVA) assume approximately normal data; non-parametric alternatives include Mann-Whitney U and Kruskal-Wallis.

Heterogeneity across studies in a meta-analysis is quantified by I-squared; values above 50% indicate substantial inconsistency.

Trial phases: I for safety and dosing, II for efficacy and dose-ranging, III for confirmatory comparison, IV for post-marketing surveillance.