Dispensing, Incompatibilities, and Adverse Drug Reactions

Flashcards covering pharmacy dispensing guidelines, parts of a prescription, medical abbreviations, prescription error types and regulations, physical and chemical incompatibilities, drug-drug, drug-food, and drug-herb interactions, adverse drug reaction classifications, teratogenicity, and NCC MERP medication error categories.

How is dispensing defined, and how does it differ from filling?

Dispensing is the sum of processes performed by a pharmacist (RPh) to provide medication with or without a prescription or medication order. Filling specifically refers to dispensing or providing medicines in accordance with a prior prescription or medication order.

What is the distinction between an outpatient prescription and an inpatient medication order?

A prescription is a written order for medication issued by an authorized prescriber (MD, DMD, DVM) intended for outpatients (written on a prescription blank). A medication order is a prescription intended for inpatients.

What are the prescription requirements for Over-the-Counter, Ethical, and Dangerous Drugs?

Over-the-Counter drugs do not require a prescription and are used for minor, self-limiting ailments. Ethical (prescription) drugs require a regular prescription for significant conditions. Dangerous Drugs require a Special Prescription Form for Dangerous Drugs (SPFDD / Yellow Rx / DDB Form 1-72) to prevent abuse and addiction.

What are the prescription requirements for Exempted Dangerous Drugs?

Exempted Dangerous Drugs (such as oral sedative-hypnotics) require a regular prescription written in triplicate accompanied by the prescriber's S2 License number.

How many Yellow Prescription booklets is a doctor permitted to have at any one time?

Every doctor is only allowed to have ten (10) booklets of Yellow Prescriptions.

How are the three copies of the Special Prescription Form for Dangerous Drugs (SPFDD) distributed?

Original (Yellow copy) is kept by the Pharmacist; Duplicate (White copy) is given to the Patient; Triplicate (Pink or Blue copy) is retained by the Prescriber.

Identify the parts of the prescription corresponding to labels 1 through 8 in the provided diagram.

1 = Prescriber's name, address, contact info, and signature/license numbers; 2 = Patient's information; 3 = Date of prescription; 4 = Superscription ($\mathbf{R_x}$); 5 = Inscription; 6 = Subscription; 7 = Signa (Transcription); 8 = Refill directions.

What is the Superscription and what Latin terms does it represent?

The superscription is represented by the symbol $\mathbf{R_x}$, which stands for the Latin term "recipe", meaning "take thou" or "you take".

What is the Inscription of a prescription?

The inscription is the body or principal part of the prescription that states the medication's name and strength, using either its generic (nonproprietary) or brand (proprietary) name. In compounded prescriptions, it lists the name and strength of each active ingredient.

What is the Subscription of a prescription?

The subscription represents directions to the dispenser/pharmacist, indicating the dosage form, compounding instructions, or total quantity/number of dosage units to dispense (e.g., "M. et ft. sol. Disp vi").

What is the Transcription or Signa?

The Signa (Sig.) represents the instructions directed to the patient indicating how, when, and how much of the prescribed medication should be taken.

What do the prescription compounding abbreviations "d.t.d", "non rep.", and "q.s. ad" mean?

"d.t.d" means give of such doses; "non rep." means do not repeat (do not refill); "q.s. ad" means a sufficient quantity to make.

What do the patient administration abbreviations "a.c.", "p.c.", "ATC", and "stat" mean?

"a.c." means before meals; "p.c." means after meals; "ATC" means around the clock; "stat" means immediately.

Differentiate the route abbreviations "a.d.", "a.s.", "a.u." from "o.d.", "o.s.", "o.u.".

"a.d." is right ear, "a.s." is left ear, and "a.u." is both ears. In contrast, "o.d." is right eye, "o.s." is left eye, and "o.u." is both eyes.

What are the common medical meanings of the drug abbreviations AZT, PTU, and TMP/SMX?

AZT is Zidovudine (the first ever drug for HIV); PTU is Propylthiouracil (alternative for methimazole in pregnant patients); TMP/SMX is Trimethoprim + Sulfamethoxazole (Co-trimoxazole, DOC for Pneumocystis pneumonia / PCP).

What are the mathematical equations used in the Cockroft-Gault formula to calculate Creatinine Clearance / GFR?

$\text{CrCl (mL/min)} = \frac{(140 - \text{Age}) \times \text{IBW}}{72 \times \text{Serum creatinine}} \times 0.85\text{ (for females)}$, where $\text{IBW (female)} = 45.5\,\text{kg} + 2.3\,\text{kg}$ for each inch over $5\,\text{ft}$, and $\text{IBW (male)} = 50\,\text{kg} + 2.3\,\text{kg}$ for each inch over $5\,\text{ft}$.

What constitutes an Erroneous Prescription and how should it be handled by a pharmacist?

An Erroneous prescription has an error in format: brand name precedes generic name, generic name is enclosed in parentheses, or brand name is not in parentheses. Handling: Fill the prescription, then REPORT the error.

What constitutes a Violative Prescription and how must it be handled?

A Violative prescription shows prescriber brand bias: generic name is not written, generic name is not legible while brand name is legible, or "No Substitution" is written. Handling: Do Not Fill, then REPORT.

What constitutes an Impossible Prescription and how must it be handled?

An Impossible prescription occurs when only the generic name is not legible, neither generic nor brand name is legible, generic and brand names mismatch, or the prescribed drug is not FDA-registered. Handling: Do Not Fill, then REPORT, inform the prescriber about the error, and instruct the patient to obtain a new prescription.

Define pharmaceutical incompatibility and name its three general types.

Incompatibility is an undesirable reaction or event that occurs when two or more substances are combined, compromising drug quality, purity, efficacy, or safety. The three types are Physical, Chemical, and Therapeutic (Drug Interaction).

Differentiate efflorescence, deliquescence, and hygroscopicity as types of physical liquefaction.

Efflorescence is the release of water of hydration into the atmosphere (e.g., alum, citric acid). Deliquescence is the absorption of atmospheric moisture leading to dissolution/liquefaction (e.g., sodium hydroxide). Hygroscopicity is the absorption of atmospheric moisture without liquefying (e.g., sulfuric acid, silica gel, honey).

What is eutexia, and what is the composition of EMLA cream?

Eutexia is a phenomenon where combining two or more solid substances lowers their mutual melting point below room temperature, causing faster liquefaction. EMLA stands for Eutectic Mixture of Local Anesthetic, composed of Prilocaine + Lidocaine.

What physical manifestation occurs during the dehydration of an emulsion, a gel, and an ointment?

In an emulsion, dehydration causes cracking (phase separation); in a gel, it causes syneresis (aggregation/fluid exudation); in an ointment, it causes crumbling (becoming dry and powdery).

What is salting-out in physical incompatibility?

Salting-out is the separation or precipitation of an organic or volatile substance from an aqueous solution upon the addition of an electrolyte (salt) because water possesses a higher affinity for the salt ions (e.g., volatile oils precipitating from aromatic water, or acacia mucilage precipitating with salts).

What chemical decomposition occurs when aspirin is exposed to moisture, and what odor is produced?

Aspirin undergoes hydrolysis (solvolysis with water) to yield acetic acid and salicylic acid, producing a characteristic vinegar-like odor.

Differentiate gelatinization from cementation in chemical incompatibilities.

Gelatinization is the formation of a gel mass (e.g., acacia + ferric salts, collodion + phenol). Cementation is the formation of a hard, dense cake/cement at the container bottom (e.g., acacia + heavy bismuth salts forming chelates).

What are the five categories of clinical significance for drug interactions?

1. Established: well-proven in studies with strong evidence;
2. Probable: very likely with theoretical basis, but not fully proven in studies;
3. Suspected: might occur, requires further evaluation;
4. Possible: could occur, but supported by limited data;
5. Unlikely: doubtful, lacking theoretical basis and clinical evidence.

In pharmacokinetic drug distribution, what interaction mechanism is illustrated in the diagram?

Protein displacement: Drug B (precipitant) has a higher binding affinity for plasma proteins, displacing Drug A (object). This increases the free/unbound concentration of Drug A, resulting in heightened pharmacological activity and increased risk of toxicity.

Which plasma proteins primarily bind acidic/neutral drugs versus basic drugs?

Acidic and neutral drugs primarily bind to albumin, whereas basic drugs primarily bind to alpha-1 acid glycoprotein.

How does gastrointestinal motility alteration affect drug absorption when taking anticholinergics versus prokinetics/stimulant laxatives?

Anticholinergics decrease GI motility, increasing transit/contact time and thus increasing drug absorption. Stimulant laxatives (bisacodyl, senna) and prokinetics (metoclopramide) increase GI motility, decreasing contact time and thus decreasing drug absorption.

List common clinically significant hepatic enzyme inducers.

Carbamazepine, chronic alcohol consumption, Rifampicin, Phenobarbital, Griseofulvin, Phenytoin, Smoking, and St. John's Wort.

List common clinically significant hepatic enzyme inhibitors.

Sodium valproate, Isoniazid, Indinavir, Cimetidine, Ketoconazole, Fluconazole, acute alcohol consumption, Chloramphenicol, Erythromycin, Sulfonamides, Diltiazem, Disulfiram, Diphenhydramine, Ciprofloxacin, Omeprazole, Grapefruit juice, and Verapamil.

How does the principle of ion-trapping affect the excretion of barbiturates and amphetamines?

Barbiturates and salicylates (weak acids) are eliminated by urinary alkalinization using $\text{NaHCO}_3$, which ionizes the drug and traps it in the urine (HIPE principle). Amphetamines (weak bases) are eliminated by urinary acidification using $\text{NH}_4\text{Cl}$.

How do additive, synergistic, and potentiation pharmacodynamic drug interactions differ mathematically?

Additive interaction: $1 + 1 = 2$ (combined effect equals the algebraic sum of individual effects); Synergistic interaction: $1 + 1 > 2$ (combined effect is greater than the sum of separate effects, e.g., bacteriostatic + bacteriostatic = bactericidal); Potentiation: $1 + 0 = 2$ (an active drug's effect is enhanced by an inactive or helper drug).

Provide examples of chemical, pharmacologic, and physiologic/functional antagonism.

Chemical antagonism: Heparin (acidic) + Protamine Sulfate (basic) forming an inactive complex. Pharmacologic antagonism: Warfarin + Vitamin K competing at VKORC. Physiologic/Functional antagonism: Histamine (acts on $H_1$ receptors for bronchoconstriction) + Epinephrine (acts on $\beta_2$ receptors for bronchodilation).

What hazardous reaction occurs when Monoamine Oxidase Inhibitors (MAOIs) are taken with tyramine-rich foods?

MAOIs inhibit monoamine oxidase, preventing the breakdown of dietary tyramine (a potent pressor amine found in cheese and wine). Tyramine accumulates, causing severe systemic vasoconstriction and leading to a hypertensive crisis.

What is the clinical interaction between licorice and antihypertensive agents?

Licorice induces sodium and water retention, increasing intravascular blood volume and counteracting antihypertensive therapy to cause elevated blood pressure.

How do patient acetylation rates vary by race, and how does this affect drug dosing?

Fast acetylators include Filipinos, Orientals, and Eskimos, requiring higher drug doses ($\uparrow$). Slow acetylators include Africans, Americans, and Caucasians, requiring lower drug doses ($\downarrow$) to avoid toxicity from drugs like hydralazine, isoniazid, procainamide, and sulfonamides.

What are the characteristics and examples of Type A and Type B Adverse Drug Reactions?

Type A (Augmented) reactions are common, dose-dependent, predictable, and related to normal pharmacology (e.g., ACEI-induced dry cough, beta-blocker bradycardia). Type B (Bizarre) reactions are uncommon, not dose-dependent, unpredictable, and unrelated to pharmacology; they include idiosyncratic reactions (genetically determined) and hypersensitivity reactions (immune-mediated).

Define Type C, Type D, and Type E Adverse Drug Reactions and give an example of each.

Type C (Continuous): long-term, time/dose-related (e.g., Cushing syndrome from chronic steroids, tolerance, dependence); Type D (Delayed): delayed onset after exposure (e.g., teratogenicity, DES-induced vaginal adenocarcinoma); Type E (End of Use): occurs upon abrupt discontinuation (e.g., rebound hypertension with clonidine, Addison's disease with steroids).

What notable adverse reaction is associated with antipsychotics, and what is its drug of choice (DOC)?

Antipsychotics can cause malignant hyperthermia, for which Dantrolene is the drug of choice.

What are the immunologic mediators and onset times for the four Gell and Coombs hypersensitivity reactions?

Type I (Anaphylactic): mediated by $\text{IgE}$, onset in hours (allergies); Type II (Cytotoxic): mediated by $\text{IgG}$ and $\text{IgM}$, onset in hours to days (blood dyscrasias, aplastic anemia); Type III (Immune complex): mediated by $\text{IgG}$ and $\text{IgM}$, onset in hours to days (serum sickness, SLE); Type IV (Delayed/Cell-mediated): mediated by T-cells, onset in days (poison ivy contact dermatitis, tuberculin skin test).

How are FDA Pregnancy Categories A, B, C, D, and X defined regarding animal and human fetal risk?

Category A: Animal (-), Human (-), safest (Levothyroxine); Category B: Animal (-), Human (?), relatively safe (Co-Amoxiclav); Category C: Animal (+), Human (?), risk cannot be ruled out (Rifampicin); Category D: Animal (+), Human (+), positive evidence of human fetal risk but benefits may outweigh risks (Phenytoin); Category X: Animal (+), Human (+), contraindicated in pregnancy due to proven teratogenicity.

Match the teratogenic drugs Lithium, Methimazole, Thalidomide, and Tetracycline to their classic fetal malformations.

Lithium causes Ebstein's anomaly; Methimazole causes aplasia cutis congenita; Thalidomide causes phocomelia (seal limbs); Tetracycline causes permanent tooth discoloration and bone growth impairment (contraindicated in patients $< 5$ years of age).

Differentiate medication errors of commission from medication errors of omission.

Errors of commission involve doing something wrong (e.g., prescribing the wrong medication or administering an incorrect dose). Errors of omission involve failing to do the right thing (e.g., failing to administer an ordered antidote during drug toxicity).

In the NCC MERP Index, which categories represent errors that reached the patient without causing harm versus errors causing harm?

Category C reached the patient without causing harm. Category D reached the patient, caused no harm, but required monitoring or intervention to prevent harm. Categories E through I caused patient harm (E: temporary harm requiring intervention; F: prolonged hospitalization; G: permanent harm; H: near-death intervention required; I: death).