General Pharmacology Practice Questions

Q: Which of the following drugs has a narrow therapeutic index?

Lithium. **Explanation:** The **Therapeutic Index (TI)** is the ratio of the dose that produces toxicity to the dose that produces the clinically desired effect ($TI = TD_{50} / ED_{50}$). A **narrow therapeutic index** indicates that the margin between the effective dose and the toxic dose is very small, requiring precise dosing and frequent monitoring. **Why Lithium is Correct:** Lithium is a classic example of a drug with a very narrow therapeutic index (0.6 to 1.2 mEq/L). Levels above 1.5 mEq/L can lead to severe toxicity (tremors, ataxia, seizures). Because its therapeutic range is so close to its toxic range, **Therapeutic Drug Monitoring (TDM)** is mandatory to ensure patient safety. **Analysis of Incorrect Options:** * **Desipramine:** While Tricyclic Antidepressants (TCAs) can be toxic in overdose, they generally have a wider safety margin compared to Lithium. * **Penicillin:** This is a "large therapeutic index" drug. It is remarkably safe even at very high doses (except in cases of hypersensitivity/allergy), as it targets bacterial cell walls which humans do not possess. * **Diazepam:** Benzodiazepines have a high therapeutic index. Even massive ingestions rarely cause fatal respiratory depression unless combined with other CNS depressants like alcohol. **NEET-PG High-Yield Pearls:** * **Mnemonic for Narrow Therapeutic Index drugs:** "**W**arfarin, **T**heophylline, **D**igoxin, **L**ithium, **P**henytoin" (**W**ith **T**he **D**og **L**ucy **P**laying). * Other notable NTI drugs: Aminoglycosides, Carbamazepine, Cyclosporine, and Amphotericin B. * Drugs with a high TI (e.g., Penicillin, Paracetamol) are generally safer and do not require routine TDM.

Q: What is the shelf life of salbutamol in this preparation?

3 years. ***3 years*** - The **drug label** clearly indicates a **shelf life of 3 years**, which is the standard duration for salbutamol preparations under proper storage conditions. - **Shelf life** refers to the period during which the medication maintains its **potency**, **safety**, and **stability** when stored according to manufacturer specifications. *14 years* - This duration is **unrealistically long** for most pharmaceutical preparations, including salbutamol inhalers. - Pharmaceutical products typically have shelf lives ranging from **1-5 years**, with 14 years being far beyond acceptable stability limits. *5 years* - While **5 years** is within the typical range for some medications, it is **not indicated** on this specific salbutamol preparation label. - The **actual shelf life** is determined by **stability testing** and varies between different formulations and manufacturers. *Cannot be known from the information* - The shelf life **can be determined** from the information provided on the drug label, making this option incorrect. - Pharmaceutical labels are **legally required** to display **expiration dates** and shelf life information for patient safety.

Q: A farmer presented in the OPD clinic with sweating, lacrimation, and pinpoint pupils. What type of poisoning is suspected?

Organophosphate poisoning. **Explanation:** The clinical presentation of **sweating, lacrimation, and pinpoint pupils (miosis)** represents a classic **Cholinergic Toxidrome**. This occurs due to the excessive accumulation of acetylcholine at the synaptic cleft, leading to overstimulation of muscarinic and nicotinic receptors [1]. **Why Organophosphate (OP) Poisoning is Correct:** Organophosphates are irreversible inhibitors of the enzyme **Acetylcholinesterase** [3]. In a rural setting, a farmer is frequently exposed to these compounds via pesticides [1], [4]. The symptoms follow the **DUMBELS** mnemonic: Diarrhea, Urination, Miosis, Bradycardia/Bronchospasm, Emesis, Lacrimation, and Salivation/Sweating [1]. The presence of pinpoint pupils and excessive secretions is pathognomonic for OP poisoning. **Why Other Options are Incorrect:** * **Dhatura and Atropine Poisoning:** These are **Anticholinergic** agents. They present with the exact opposite symptoms: dry skin (no sweating), dry mouth, and **mydriasis** (dilated pupils). The classic description is "Dry as a bone, Red as a beet, Blind as a bat, Mad as a hatter." * **Cocaine Poisoning:** Cocaine is a sympathomimetic stimulant. It causes **mydriasis** (dilated pupils) due to increased sympathetic activity, along with tachycardia and hypertension [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** The specific antidote is **Atropine** (to reverse muscarinic effects) and **Pralidoxime (2-PAM)** (to regenerate cholinesterase, must be given before "aging" of the enzyme occurs) [5]. * **Monitoring:** The adequacy of atropinization is best monitored by the **drying of pulmonary secretions** and an increase in heart rate, rather than pupil size alone. * **Diagnosis:** Confirmed by measuring **Red Blood Cell (RBC) cholinesterase levels**, which is more specific than plasma cholinesterase.

Q: All the following regarding prostaglandin analogues are true except?

Carboprost: Peptic ulcer. This question tests your knowledge of prostaglandin (PG) analogues and their specific clinical applications, a high-yield topic in General Pharmacology. [1] ### **Explanation of the Correct Answer** **Option B (Carboprost: Peptic ulcer)** is the incorrect statement. **Carboprost** is a **PGF2̱̱ analogue** primarily used in obstetrics for the management of **Postpartum Hemorrhage (PPH)** and for mid-trimester abortions due to its potent uterine-contracting properties. [4] For **Peptic Ulcer**, the prostaglandin analogue used is **Misoprostol (PGE1 analogue)**. [1] Misoprostol acts as a cytoprotective agent by increasing bicarbonate and mucus secretion and inhibiting gastric acid production. It is specifically indicated for preventing NSAID-induced gastric ulcers. [2] ### **Analysis of Other Options** * **A. Alprostadil (PGE1):** Used for **Erectile Dysfunction** (via intracavernosal injection) and to maintain the patency of the **Ductus Arteriosus** in neonates with congenital heart defects. [1] * **C. Iloprost (PGI2/Prostacyclin):** A potent vasodilator used in the treatment of **Pulmonary Arterial Hypertension (PAH)** and Buerger's disease. [1] * **D. Travoprost (PGF2̱̱):** Along with Latanoprost and Bimatoprost, it is a first-line agent for **Open-Angle Glaucoma** as it increases uveoscleral outflow. [1] [2] ### **NEET-PG High-Yield Pearls** * **Latanoprost Side Effect:** Can cause permanent darkening of the iris (increased pigmentation) and thickening/lengthening of eyelashes. * **Dinoprostone (PGE2):** Used for cervical ripening and induction of labor. [3] * **Epoprostenol (PGI2):** Used in pulmonary hypertension; has a very short half-life. [1] * **Misoprostol Contraindication:** Absolutely contraindicated in pregnancy (unless used for abortion) as it is highly **teratogenic** and can cause uterine rupture.

Q: Which of the following drugs is not administered sublingually?

Isosorbide-5-mononitrate. **Explanation:** The correct answer is **Isosorbide-5-mononitrate (ISMN)**. **Why Isosorbide-5-mononitrate is not given sublingually:** The primary rationale for sublingual administration is to bypass **first-pass metabolism** in the liver, ensuring rapid onset of action. Isosorbide-5-mononitrate is the active metabolite of Isosorbide dinitrate. It possesses **100% oral bioavailability** and is not subject to significant first-pass metabolism. Therefore, there is no clinical advantage to administering it sublingually; it is designed for oral use to provide a sustained effect for the prophylaxis of angina. **Analysis of Incorrect Options:** * **Isosorbide dinitrate (ISDN):** This drug undergoes extensive first-pass metabolism. The sublingual route is commonly used for the acute termination of an angina attack due to its rapid absorption into the systemic circulation. * **Buprenorphine:** This is a highly lipid-soluble opioid with high first-pass metabolism. Sublingual tablets are a standard formulation for treating opioid dependence and severe pain. * **Ergotamine tartrate:** Used in the treatment of acute migraine attacks, it is administered sublingually to ensure rapid absorption and to bypass the gastric stasis often associated with migraine. **High-Yield Clinical Pearls for NEET-PG:** * **Sublingual Route Advantages:** Rapid onset, bypasses first-pass metabolism, bypasses gastric acid, and can be self-terminated by spitting out the tablet. * **Nitrate Comparison:** * **GTN (Nitroglycerin):** Drug of choice for acute angina (Sublingual). * **ISDN:** Used for both acute (Sublingual) and chronic (Oral) management. * **ISMN:** Used only for chronic prophylaxis (Oral) due to its long half-life and excellent bioavailability. * **Other Sublingual Drugs:** Desmopressin, Nifedipine (historically for hypertensive emergencies, though now discouraged), and Fentanyl.

Question 1

What is acute or rapidly developing tolerance to a drug?

Accepted Answer

Teratogenic effects

Answer

Anaphylaxis

Answer

Induction

Answer

Supersensitivity

Question 2

Which of the following drugs has a narrow therapeutic index?

Accepted Answer

Lithium

Answer

Desipramine

Answer

Penicillin

Answer

Diazepam

Question 3

A widely used drug that suppresses cellular immunity, inhibits prostaglandin and leukotriene synthesis, and increases the catabolism of IgG antibody is:

Accepted Answer

Prednisone

Answer

Cyclophosphamide

Answer

Cyclosporine

Answer

Infliximab

Question 4

Most essential medicines should be formulated as which of the following?

Accepted Answer

Single compound

Answer

No compound

Answer

Multiple compounds

Answer

Fixed dose combinations

Question 5

Which drug possesses antagonistic action at histamine, serotonin, and muscarinic receptors?

Accepted Answer

Cyproheptadine

Answer

Promethazine

Answer

Terfenadine

Answer

Hydroxyzine

Question 6

What is the shelf life of salbutamol in this preparation?

Accepted Answer

3 years

Answer

14 years

Answer

5 years

Answer

Cannot be known from the information

Question 7

A farmer presented in the OPD clinic with sweating, lacrimation, and pinpoint pupils. What type of poisoning is suspected?

Accepted Answer

Organophosphate poisoning

Answer

Dhatura poisoning

Answer

Atropine poisoning

Answer

Cocaine poisoning

Question 8

What is the typical sequence of clinical trials for a new drug?

Accepted Answer

FDA approval - NDA submission - Post marketing surveillance

Answer

New Drug Application (NDA) - Food and Drug Administration (FDA) approval - NDA resubmission

Answer

FDA approval - NDA submission - FDA approval

Answer

FDA approval - Marketing - NDA submission

Question 9

All the following regarding prostaglandin analogues are true except?

Accepted Answer

Carboprost: Peptic ulcer

Answer

Alprostadil: Erectile dysfunction

Answer

Iloprost: Pulmonary hypertension

Answer

Travoprost: Glaucoma

Question 10

Which of the following drugs is not administered sublingually?

Accepted Answer

Isosorbide-5-mononitrate

Answer

Isosorbide dinitrate

Answer

Buprenorphine

Answer

Ergotamine tartrate

General Pharmacology — MCQs

General Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?