• Shruti GOCHHWAL

Drugs

A substance that, when either ingested, inhaled, injected or absorbed by the body, alters the functioning of the body either physically or psychologically.

The effects of drugs are very strong but that is not necessarily a good thing.

Some strong drugs, when taken in certain amounts, are not beneficial to the body. In fact, they produce harmful negative side effects and are often followed by overdosing and death.

This is known as drug abuse and it leads to drug addiction when people start to crave the feeling of euphoria, numbness and hallucinations that they experience during intoxication.

On the positive side, drugs are extremely effective when administered correctly by doctors. They are one of the most important and valuable medical items.

Drugs are used for important diagnosis, cure, treatment and prevention of diseases. They are also used in derma products and cosmetics.

Drugs in India

To avoid misbranding, use of harmful ingredients, adulterations and substandard quality of drugs and cosmetics, the parliament of India established the drugs and cosmetics act in 1940.

The act has been changed many times but stays the same in essence.

The Drugs and Cosmetics Act

It is an Act of the Indian Parliament that governs the import, production and distribution of drugs in India.

Objective: 

  1. To monitor the marketing and licensing of medications and cosmetics

  2. To ensure the manufacturer, distribution and sale by qualified persons only.

  3. To maintain high standards of production.

  4. To govern Ayurvedic, Siddha and Unani production and distribution.

  5. Establishment of Drugs Technical Advisory Board and Drug Consultative Committees.

Features:

  1. To maximize the sentence and impose a fine of Rs. 10 lakhs or 3 times the amount of the items confiscated.

  2. Authorization for the initiation of prosecution under the Act by gazette officers and the Drug Controller Office;

  3. Special courts for prosecution of crimes protected by the Act and provision for mixed offenses.

Credit: foter caption: drug and cosmetics act

Some important terms defined by the act:

Drugs: 

  1. Both internal or external use of drugs to human and animal and all chemicals used to diagnose, cure, mitigate or avoid any illness in humans and animals.

  2. This material is meant (other than food) to influence the body’s structure or some other feature, or is intended to be used for removal of vermin or insects that cause disease in people or animals.

  3. All the substances intended for use as components of drug including empty gelatin capsule 

Pharmaceutical Drugs

They are drugs used in the medical field to improve a patient’s health by restoring, correcting and biologically modifying organic functions.

They can be naturally occurring or artificially synthesized for beneficial purposes and are commonly known as medicine.

Drugs can be classified according to their level of control. 

Prescription drugs can be used or obtained only with a doctor’s prescription. They are stronger in nature with more side effects and must be taken in calculated quantities.  Over-the-counter drugs are medicines that can be self-administered and they significantly have lesser risk of negative side effects.

Credits: unsplash Caption: pharmaceutical drugs

Various types of pharmaceutical drugs

  1. Antiarrhythmic drugs are compounds used to treat cardiac arrhythmias.

Arrhythmia is the disturbance in the irregular rate, rhythm and impulse of the heartbeat. They can damage the cardiac function and be extremely life-threatening.

Disturbances in the heartbeat or arrhythmias can either be caused when the sinus node in the atria sends excess or insufficient impulse for a heartbeat or when the muscles of the heart wall fail to respond to the impulse and contract irregularly.

The sole purpose of antiarrhythmic drugs is to bring the electrical impulse of the heart back to normal.

These drugs can be classified into 4 types: 

  1. Class 1 – Sodium-channel blockers: They slow the electrical conduction of the heart.

  2. Class 2 – Beta blocker: they block the electrical impulse of the heart and induce hormonal influences like adrenaline in the heart muscles.

  3. Class 3 – Potassium- channel blockers: They slow down the electrical impulse of the heart by blocking potassium channels.

  4. Class 4 – Calcium channel blockers: they are similar to class 3 drugs but block the heart’s calcium channels instead.

Credit: pexels Caption : heartbeat

  1. Antiplatelet drugs are medicines that prevent the formation of thrombus or blood clots.

During the time of injury, the skin gets inflamed and blood rushes to the area. The platelets are an important component of the blood that forms a cloth in order to stop the bleeding. 

This similar action can take place when blood vessels or arteries are injured but the formation of blood clots in the blood vessels or arteries could block the blood flow and lead to heart attack or strokes.

This is why antiplatelet drugs are important to ensure that the blood does not clot and block the arteries.

The medication is especially used during valve replacement and angioplasty.

  1. Cholinergic drugs are drugs which inhibit, improve or imitate the effects of acetylcholine, the neurotransmitter.

Neurotransmitters are chemical substances released by the end of nerve cells between the synapse or junction of two nerves to enable transmission of nerve impulse which is received by the receptor of the nearby nerve cell.

Cholinergic antagonist/drugs are of three types:

  1. Direct acting- They mimic the effects of acetylcholine by binding to the receptors.

Ironically, one of the drugs itself is known as acetylcholine. Its mechanism duration is very small as the drug is easily broken down by acetylcholinesterases.

Other drugs are carbachol and pilocarpine and are less susceptible to enzymatic breakdown.

  1. Indirect acting reversible and Irreversible – These drugs simply bind to acetylcholinesterase, the enzyme that breakdowns acetylcholine into acetate and choline.

Hence, since the breakdown enzyme has become inactivated after binding with the drug, it leads to a buildup of acetylcholine and enhances nerve impulse.

Credits: foter Caption: Neurotransmission through synapse

  1. Antidiabetic drugs are medicines developed to control and check the blood glucose levels in diabetic patients.

They are not designed to cure diabetes but keep all the levels in control and prevent complications related.

Since the endocrine system cannot contain insulin, diabetes is triggered. The regulation of your blood sugar levels in your body is crucial for insulin.

Lack of insulin makes the body hyperglycemic(high levels of sugar)

There are two types of diabetes: 

  1. Type 1 is characterized by the lack of production of insulin

  2. The resistance of the tissue to the insulin released by the pancreas is characteristic of type2.

The most commonly antidiabetic drug is insulin that is artificially made from recombinant DNA techno. 

It cannot be taken orally as it’s polypeptide property will be destroyed by enzymes in the stomach. 

Hence, insulin is injected directly into the bloodstream and reaches the cells.

  1. The treatment of hypertension or high blood pressure is based on Antihypertensive drugs.

In order to understand antihypertensive drugs, we must first under the regulation of blood pressure.

In blood pressure regulation, several mechanisms are involved. Pressure-sensitive neurons called baroreceptors, situated in the aortic arch and carotid sinuses of the heart, controls blood pressure.

When blood pressure is irregular, baroreceptors send signals to the adrenal medulla to increase sympathetic activity through activation of alpha and beta receptors.

Activation of Beta 1 receptors allow heart rate and stroke volume to increase heart rate and stroke volume. Therefore increasing blood pressure.

Activation of Alpha 1 receptors causes vasoconstriction which increases vascular resistance. Therefore, it also increases blood pressure.

Another system that regulates blood pressure is the renin-angiotensin-aldosterone system. Here the baroreceptors present in the kidneys get activated and release enzymes called renin and angiotensin-converting enzyme (ACE)  which ultimately increases blood pressure.

There are different antihypertensive drugs which target different systems that regulates blood pressure:

  1. Alpha 1 blockers – They block alpha one receptors on smooth muscles and hence decrease blood pressure.

  2. Selective and non selective beta blockers- They block alpha receptors causing a decrease in cardiac output and vascular resistance, leading to low blood pressure.

  3. Centrally acting adrenergic drugs- They block sympathetic activity within the brain which decreases cardiac output, again leading to decrease in blood pressure.

  4. Calcium channel blockers – When calcium ions enter smooth muscle cells, the muscles contract. 

This leads to an increase in vascular resistance and therefore blood pressure increases.

Calcium channel blocker blocks the entry of these calcium ions.

  1. Diuretics – They reduce the reabsorption of sodium chloride in the nephrons. This leads to a decrease in vascular space volume which causes less blood to flow back to the heart.

  2. Renin-angiotensin-aldosterone system – Renin inhibitors and ACE inhibitors prevent angiotensin to convert to angiotensin 1 and 2 respectively.

  3. Anticancer drugs: Cancer is a condition where specific cells in the body undergo vigorous and uncontrollable division and do not get specialised.

Anticancer drugs are chemicals that can denature cancer cells by stopping or slowing down its growth and multiplication.

Though anticancer drugs are aimed to target cancerous cells, sometimes, normal cells are also affected in the process.

Chemotherapy is known as the use of anticancer medications to cure cancer. Whenever a new cell is created, a number of steps pass to become a fully developed cell. 

These drugs target cells at different phases very quickly. However, they also cannot differentiate between normal cells sometimes but since cancer cells tend to divide quickly, it makes them a better target, so it’s easier to find balance and spare the normal cells.

In addition, most human cells can regenerate over time from chemical damage, while cancer cells do not recover from chemo effects.

Credits : unsplash Caption: Anticancer drugs

  1. Antianginal drug is used to treat angina pectoris, a type of chest pain caused due to decreased blood flow supply in the heart.

This causes a shortage of oxygen supply in the cardiac cells as they receive oxygen supply through the blood.

The drugs work in two ways:

  1. They increase blood flow and prevent clot formation and vasospasm

  2. They reduce myocardial oxygen demand to make up for the lack of oxygen supply and ease the chest pain.

They do so by dilating arteries and veins with vasodilators, reducing heart rate and contractility and preventing thrombus formation with anticoagulants.

Credit: unsplash Caption: Birth control pills

  1. Antifertility drugs are also known as “birth control pills”.

These drugs prevent pregnancy by suppress the action of hormones that promotes it.

They consist of derivatives of synthetic progesterone or a combination of progesterone and estrogen which is the most effective type.

Mechanism of antifertility drugs: When progesterone pills are taken, the hormone increases the level of mucus produced in the cervix, the opening into the virginal tract. 

As the mucus accumulates and gets thickened, it is very difficult for the sperm to enter the uterus and fertilize the egg.

In addition, these hormones interfere and inhibit ovulation in the menstrual cycle.

This is because progesterone and estrogen suppresses levels of FSH and LH hormone. FFSH encourages the maturation of the egg and LH causes egg release during ovulation.

Thus, when these levels are suppressed, no egg will be formed or released. It is almost a fool-proof way to ensure no chances of getting pregnant.

Nephrotoxic drugs: Side effects of drugs

Some drugs have poisonous effects on the kidneys, causing renal injuries and effects on its function.

This is known as nephrotoxicity and it is caused by different mechanisms of actions of drugs. It could even lead to acute kidney failure.

They are three ways drugs can damage the kidneys;

  1. Some drugs decrease the amount of blood that flows to the kidneys. Example: NSAIDs, ACE inhibitors and ARBs.

  2. There are drugs that injure the kidneys directly. Example: penicillin and contrast dyes.

  3. Some drugs obstruct the flow of urine in the kidneys.

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