Match List I with List II

Choose the correct answer from the options given below:

A-II, B-IV, C-I, D-III

The correct answer is option 4. A-II, B-IV, C-I, D-III.

Let us explore each drug and its corresponding pharmacological activity in detail:

(A) Norethindrone → (II) Antifertility drug:

Norethindrone is a synthetic form of progesterone, a hormone naturally produced in the body. It is commonly used in oral contraceptives (birth control pills).

Mechanism of Action: Norethindrone works by inhibiting ovulation (the release of an egg from the ovaries), thickening cervical mucus to block sperm, and altering the lining of the uterus to prevent implantation of a fertilized egg.

Use: Because of these effects, Norethindrone is classified as an antifertility drug. It is used for preventing pregnancy, treating menstrual disorders, and managing endometriosis.

(B) Chloramphenicol → (IV) Broad-spectrum antibiotic

Chloramphenicol is an antibiotic that was once widely used due to its effectiveness against a broad range of bacterial infections.

Mechanism of Action: It works by inhibiting protein synthesis in bacteria, specifically by binding to the 50S ribosomal subunit, which prevents the growth and replication of bacteria.

Use: Chloramphenicol is considered a broad-spectrum antibiotic because it is effective against both Gram-positive and Gram-negative bacteria. It is used to treat serious infections such as typhoid fever, meningitis, and eye infections. However, due to its potential severe side effects, like aplastic anemia, its use is now limited.

(C) Luminal (Phenobarbital) → (I) Tranquilizer

Luminal, also known as Phenobarbital, is a barbiturate, a class of drugs that depresses the central nervous system (CNS).

Mechanism of Action: Phenobarbital enhances the action of the neurotransmitter GABA (gamma-aminobutyric acid) by binding to GABA receptors, leading to increased chloride ion flow into neurons and hyperpolarization, which reduces neuronal activity.

Use: It is used as a tranquilizer (or sedative) to treat conditions like anxiety, insomnia, and seizures. Due to its CNS depressant effects, it has a calming effect and can induce sleep or reduce seizure activity in epilepsy.

(D) Seldane (Terfenadine) → (III) Antihistamine drug

Seldane is the brand name for Terfenadine, an antihistamine that was used to treat allergic reactions.

Mechanism of Action: Terfenadine works by blocking H1 histamine receptors, preventing histamine from binding and causing allergic symptoms such as itching, sneezing, and hives.

Use: It is classified as an antihistamine drug. However, Seldane was withdrawn from the market in many countries due to its potential to cause serious cardiac arrhythmias when taken with certain other medications.

Summary

Norethindrone: Antifertility drug (prevents pregnancy by affecting ovulation and the uterine lining).

Chloramphenicol: Broad-spectrum antibiotic (effective against a wide range of bacterial infections).

Luminal (Phenobarbital): Tranquilizer (used to calm the nervous system, treat anxiety, and control seizures).

Seldane (Terfenadine): Antihistamine drug (used to treat allergic reactions).

This corresponds to Option 4: A-II, B-IV, C-I, D-III.