Clinical Pharmacology and Drug Toxicity Practice Questions

Q: Toxic shock syndrome occurs after one of the following vaccinations :

DPT. ***DPT*** - Toxic shock syndrome has been **extremely rarely reported in isolated case reports following DPT** (diphtheria, pertussis, tetanus) vaccination, though it is **not a recognized or established complication** in standard medical literature. - The association is controversial and based on very limited data. Any potential link may be related to coincidental bacterial infection rather than a direct vaccine effect. - Among the options listed, this has the most (though minimal) reported association with **TSS-like reactions** in historical case reports. *Measles vaccine* - The measles vaccine is a **live attenuated vaccine** and does not cause toxic shock syndrome. - Its adverse effects are usually related to a mild form of the disease or allergic reactions, not **bacterial toxin-mediated illnesses like TSS**. *BCG vaccine* - The BCG (Bacille Calmette-Guérin) vaccine is used against tuberculosis and is a **live attenuated vaccine**. - Adverse effects are commonly local reactions or disseminated BCG disease in immunocompromised individuals, not **toxic shock syndrome**. *Recombinant DNA Vaccine against Hepatitis B* - Recombinant DNA vaccines, like the Hepatitis B vaccine, are highly purified and contain **no live pathogens or bacterial toxins**. - They are associated with very few severe adverse events, none of which include **toxic shock syndrome**.

Q: Misoprostol can be used in obstetric practice by the following routes except:

Intravenous. ***Intravenous*** - Misoprostol is **not used intravenously** in obstetric practice due to safety concerns - IV administration could lead to **rapid, uncontrolled systemic effects** including severe adverse events like **cardiovascular collapse** and anaphylactoid reactions - The drug formulation is not intended for IV use, and its rapid absorption via this route would pose significant maternal risk - All approved obstetric uses employ **oral, sublingual, vaginal, or buccal routes** *Vaginal* - Vaginal administration is commonly used in obstetrics for **cervical ripening** and **labor induction** - Also used for **management of miscarriage** and **postpartum hemorrhage** - Allows for **gradual absorption** with local effect on the cervix and uterus *Sub-lingual* - Sublingual misoprostol is effectively absorbed through the **oral mucosa** - Used for **labor induction** and **management of postpartum hemorrhage** - Offers **rapid onset of action** and bypasses first-pass metabolism *Oral* - Oral administration is used for **medical abortion**, **miscarriage management**, and **labor induction** - Also approved for prevention of **NSAID-induced gastric ulcers** (non-obstetric indication) - Absorption is slower with lower peak concentrations compared to sublingual or vaginal routes

Q: Which of the following local anaesthetics causes irreversible cardiac arrest if it is given intravenously ?

Bupivacaine. ***Bupivacaine*** - Bupivacaine is known for its **cardiotoxicity**, which can lead to severe and often irreversible **cardiac arrest** if inadvertently administered intravenously. - This is due to its high potency, slow dissociation from cardiac sodium channels, and increased lipid solubility, leading to prolonged cardiac depression. *Lignocaine* - While lignocaine (lidocaine) can cause cardiac toxicity in overdose, it is generally considered less cardiotoxic than bupivacaine, and cardiac arrest is more readily reversible. - It is commonly used intravenously as an antiarrhythmic, indicating a safer cardiac profile at therapeutic doses. *Cocaine* - Cocaine is a vasoconstrictor and stimulant; its primary cardiovascular effects are **tachycardia**, hypertension, and arrhythmias due to inhibition of norepinephrine reuptake, rather than direct myocardial depression leading to irreversible cardiac arrest from intravenous injection in the same manner as bupivacaine. - Cocaine toxicity can cause myocardial ischemia and infarction, but not the same profound, irreversible cardiac depression seen with bupivacaine. *Prilocaine* - Prilocaine is associated with **methemoglobinemia** as a dose-dependent side effect, especially in large doses, due to its metabolite o-toluidine. - While it can cause cardiovascular depression at very high doses, it does not have the same potent and often irreversible direct negative inotropic effects on the heart as bupivacaine.

Q: Which one of the following is an absolute contraindication for administration of killed vaccine?

Severe reaction to a previous dose. ***Severe reaction to a previous dose*** * A **severe allergic reaction** (e.g., **anaphylaxis**) to a previous dose of any vaccine or its components is an **absolute contraindication** to further doses of that vaccine. * This is due to the potential for a life-threatening anaphylactic response upon re-exposure to the allergen. *Hodgkin's disease* * While Hodgkin's disease is a **malignancy** that can affect the immune system, it is generally considered a **precaution** or a reason to defer live vaccines, not an absolute contraindication for killed vaccines. * **Killed vaccines** are generally safe in immunocompromised patients, though their efficacy may be reduced. *Pregnancy* * **Pregnancy** is a contraindication for certain **live attenuated vaccines** (e.g., MMR, varicella) due to the theoretical risk of fetal infection. * However, most **killed vaccines** (e.g., inactivated influenza, tetanus, diphtheria, acellular pertussis) are **safe and often recommended** during pregnancy for maternal and fetal protection. *Immunodeficiency* * **Immunodeficiency** (e.g., HIV/AIDS, chemotherapy) is primarily a contraindication for **live attenuated vaccines**, as these can cause disseminated infection in immunocompromised individuals. * **Killed vaccines** are generally safe in immunocompromised individuals, although the **immune response may be suboptimal**, and repeat doses or higher doses may be necessary.

Q: Match List-I with List-II and select the correct answer using the code given below the Lists:

A→4 B→3 C→1 D→2. ***A→4 B→3 C→1 D→2*** - **Oral polio vaccine (OPV)** is a live attenuated vaccine, and a rare but serious adverse effect is vaccine-associated paralytic poliomyelitis (VAPP), which manifests as **paralysis**. - **BCG vaccine** (Bacillus Calmette-Guérin) is used against tuberculosis. A known adverse effect, particularly in immunocompromised individuals, is **suppurative lymphadenitis**, where regional lymph nodes become inflamed and may form abscesses. - **Pertussis vaccine** (whole-cell DTP) can cause reactions such as persistent inconsolable screaming, high fever, and, very rarely, encephalopathy. **Persistent inconsolable screaming** is a recognized adverse reaction to the pertussis component. - **Measles vaccine** is a live attenuated vaccine. While generally safe, rare severe adverse effects include **encephalopathy** (or encephalitis). *A→3 B→4 C→1 D→2* - This option incorrectly associates oral polio vaccine with suppurative lymphadenitis and BCG with paralysis, contradicting established vaccine adverse effects. - Oral polio has a risk of paralysis, not lymphadenitis, whereas BCG can cause lymphadenitis. *A→2 B→1 C→4 D→3* - This option incorrectly links oral polio to encephalopathy and BCG to persistent inconsolable screaming. - Encephalopathy is associated with measles or pertussis, and persistent screaming with pertussis, not oral polio or BCG. *A→1 B→2 C→3 D→4* - This option incorrectly attributes persistent inconsolable screaming to oral polio and encephalopathy to BCG. - Paralysis is a known complication of oral polio, and suppurative lymphadenitis is a key adverse effect of BCG.

Q: Intramuscular injection of iron dextran is given by ‘Z’ technique to:

Reduce the staining. ***Reduce the staining*** - The **Z-track technique** creates a staggered path that prevents the dark iron solution from leaking back into the subcutaneous tissue, which can cause **permanent skin discoloration or staining**. - This method seals the medication deep in the muscle, preventing its reflux along the needle track. *Increase the iron absorption* - The Z-track technique is primarily about preventing **leakage and staining**, not enhancing the absorption rate of the iron. - Iron absorption is largely determined by factors like the patient's iron deficiency status and the form of iron administered, not the injection technique. *Alleviate the pain* - While proper injection technique can minimize discomfort, the Z-track method's primary purpose is not pain reduction but rather **preventing reflux** and associated staining. - Pain during injection is often related to the volume, viscosity, and acidity of the medication, as well as the injection site. *Decrease the incidence of infection* - Standard aseptic techniques, not the Z-track method itself, are crucial for **preventing infection** during intramuscular injections. - The Z-track technique does not inherently reduce the risk of infection beyond what is achieved with good sterile practice.

Q: Absolute contraindication to combined oral contraceptive is:

History of thrombo-embolism. ***History of thrombo-embolism*** - A history of **thromboembolism** (e.g., DVT, pulmonary embolism) is an **absolute contraindication** to combined oral contraceptives (COCs) due to the increased risk of further thrombotic events associated with estrogen. - COCs, particularly their estrogen component, can increase levels of clotting factors and decrease natural anticoagulants, significantly raising the risk of **venous thromboembolism (VTE)**. *History of gallbladder disease* - A history of **gallbladder disease** is generally considered a **relative contraindication** rather than an absolute one for COCs. - While COCs may exacerbate pre-existing gallbladder conditions or increase the risk of gallstone formation in some individuals, it doesn't preclude their use in all cases. *History of GDM* - A history of **gestational diabetes mellitus (GDM)** is a **relative contraindication** or caution for COC use, particularly in women with additional risk factors for diabetes. - While COCs can affect glucose tolerance, they are not absolutely contraindicated unless the woman has developed overt diabetes or has poorly controlled metabolic issues. *History of previous two caesarean section* - A history of previous **two cesarean sections** is **not a contraindication** to combined oral contraceptive use. - This obstetric history does not impact the metabolic or thrombotic risks associated with COCs, and thus, does not directly interact with their safety profile.

Q: Which of the following drugs should be avoided in the first-line ART regimens because of its well recognized metabolic toxicities ?

Stavudine (d4T). ***Stavudine (d4T)*** - **Stavudine** is a **nucleoside reverse transcriptase inhibitor (NRTI)** that is well-known for its significant **metabolic toxicities**, including **lipoatrophy**, peripheral neuropathy, and lactic acidosis [1]. - Due to these severe side effects, it is no longer recommended for first-line ART regimens and its use is generally avoided. *Tenofovir (TDF)* - While Tenofovir (TDF) can cause **renal toxicity** and **bone mineral density loss** [2], it is generally considered a safer option than stavudine regarding severe metabolic toxicities like lipoatrophy. - TDF is commonly used in first-line ART regimens, often in combination with other drugs. *Zidovudine (AZT)* - **Zidovudine** is associated with side effects such as **bone marrow suppression** (leading to anemia and neutropenia), myopathy, and gastrointestinal upset, but not typically the severe metabolic toxicities seen with stavudine. - It is still used in some ART regimens, particularly for prevention of mother-to-child transmission. *Lamivudine (3TC)* - **Lamivudine** is generally well-tolerated with a favorable side effect profile, primarily mild gastrointestinal symptoms, and is rarely associated with significant metabolic toxicities. - It is a cornerstone drug in many first-line ART regimens due to its efficacy and safety.

Q: Which of the following statements regarding the composition of common crystalloid solutions is correct ?

Normal saline contains 154 mEq/L of Na+. ***Normal saline contains 154 mEq/L of Na+*** - Normal saline (0.9% NaCl) contains **154 mEq/L of both Na+ and Cl-**, making this statement factually correct. - This makes normal saline **hypernatremic and hyperchloremic** compared to plasma (which has ~140 mEq/L Na+ and ~103 mEq/L Cl-). - Normal saline is useful for correcting **hyponatremia** and for significant volume expansion, but large volumes can cause **hyperchloremic metabolic acidosis**. *Hartmann's solution contains 140 mEq/L of Na+* - Hartmann's solution (Lactated Ringer's) actually contains approximately **130 mEq/L of Na+**, not 140 mEq/L. - The sodium content is designed to be closer to that of **plasma**, making it a more physiologically balanced solution. *Hartmann's solution contains 120 mEq/L of Cl-* - Hartmann's solution contains approximately **109-110 mEq/L of Cl-**, not 120 mEq/L. - This **lower chloride content** compared to normal saline, along with the presence of lactate (28 mEq/L), contributes to a reduced risk of hyperchloremic metabolic acidosis. - The lactate is metabolized to bicarbonate, providing a mild alkalinizing effect. *Normal saline contains 140 mEq/L of Cl-* - Normal saline contains **154 mEq/L of Cl-**, not 140 mEq/L. - Its high chloride content can lead to **hyperchloremic metabolic acidosis** with large-volume administration.

Q: Absolute contraindication for the use of OCPs is:

Thromboembolism. ***Thromboembolism*** - A **current or past history of thromboembolism** (e.g., DVT, pulmonary embolism) is an **absolute contraindication (WHO MEC Category 4)** for combined oral contraceptive pills (OCPs) due to the significantly increased risk of recurrent thrombotic events. - Exogenous **estrogen** in OCPs increases the synthesis of clotting factors (II, VII, IX, X, fibrinogen) and decreases anticoagulant proteins (protein S, antithrombin), thereby promoting a hypercoagulable state. - Even a remote history of VTE makes OCPs absolutely contraindicated. *Diabetes* - Diabetes **with vascular complications** (retinopathy, nephropathy, neuropathy) or diabetes of >20 years duration is a contraindication (WHO MEC Category 3/4). - However, **uncomplicated diabetes without vascular disease** is not an absolute contraindication for OCPs. - Among the options listed, thromboembolism is the clearest absolute contraindication. *Epilepsy* - Epilepsy itself is **not a contraindication** for OCPs (WHO MEC Category 1). - However, some **enzyme-inducing antiepileptic drugs** (phenytoin, carbamazepine, phenobarbital, topiramate) can reduce OCP efficacy by increasing hepatic metabolism of contraceptive hormones. - In such cases, higher-dose OCPs, alternative methods, or non-enzyme-inducing AEDs should be considered. *Hypertension* - **Severe or uncontrolled hypertension** (≥160/100 mmHg) or hypertension with vascular disease is an absolute contraindication (WHO MEC Category 4). - **Adequately controlled and monitored hypertension** is a relative contraindication (WHO MEC Category 3), not an absolute one. - Among the given options, thromboembolism represents a clearer and more universally accepted absolute contraindication.

Question 1

Toxic shock syndrome occurs after one of the following vaccinations :

Accepted Answer

DPT

Answer

Measles vaccine

Answer

BCG vaccine

Answer

Recombinant DNA Vaccine against Hepatitis B

Question 2

Misoprostol can be used in obstetric practice by the following routes except:

Accepted Answer

Intravenous

Answer

Vaginal

Answer

Sub-lingual

Answer

Oral

Question 3

Which of the following local anaesthetics causes irreversible cardiac arrest if it is given intravenously ?

Accepted Answer

Bupivacaine

Answer

Lignocaine

Answer

Cocaine

Answer

Prilocaine

Question 4

Which one of the following is an absolute contraindication for administration of killed vaccine?

Accepted Answer

Severe reaction to a previous dose

Answer

Hodgkin's disease

Answer

Pregnancy

Answer

Immunodeficiency

Question 5

Match List-I with List-II and select the correct answer using the code given below the Lists:

Accepted Answer

A→4  B→3  C→1  D→2

Answer

A→3  B→4  C→1  D→2

Answer

A→2  B→1  C→4  D→3

Answer

A→1  B→2  C→3  D→4

Question 6

Intramuscular injection of iron dextran is given by ‘Z’ technique to:

Accepted Answer

Reduce the staining

Answer

Increase the iron absorption

Answer

Alleviate the pain

Answer

Decrease the incidence of infection

Question 7

Absolute contraindication to combined oral contraceptive is:

Accepted Answer

History of thrombo-embolism

Answer

History of gallbladder disease

Answer

History of GDM

Answer

History of previous two caesarean section

Question 8

Which of the following drugs should be avoided in the first-line ART regimens because of its well recognized metabolic toxicities ?

Accepted Answer

Stavudine (d4T)

Answer

Tenofovir (TDF)

Answer

Zidovudine (AZT)

Answer

Lamivudine (3TC)

Question 9

Which of the following statements regarding the composition of common crystalloid solutions is correct ?

Accepted Answer

Normal saline contains 154 mEq/L of Na+

Answer

Hartmann's solution contains 120 mEq/L of Cl-

Answer

Hartmann's solution contains 140 mEq/L of Na+

Answer

Normal saline contains 140 mEq/L of Cl-

Question 10

Absolute contraindication for the use of OCPs is:

Accepted Answer

Thromboembolism

Answer

Diabetes

Answer

Epilepsy

Answer

Hypertension

Clinical Pharmacology and Drug Toxicity — MCQs

Clinical Pharmacology and Drug Toxicity — MCQs

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