Classification of Drugs and Diseases

 

Anatomical Classification of Drugs

    Drugs can be classified anatomically based on their primary site of action or target organ within the body. Here are some common anatomical classifications of drugs:

1. Central Nervous System (CNS) Drugs:

These drugs primarily affect the brain and spinal cord. They can be further classified into various subcategories such as: 

a) Psychotropic Drugs: 

These drugs are used to treat mental disorders and affect the brain's neurotransmitter systems. Examples include antidepressants, antipsychotics, anxiolytics (anti-anxiety drugs), and mood stabilizers.

b) Analgesics:

These drugs are used to relieve pain and can act on the CNS. They include opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and local anesthetics.

c) Sedatives and Hypnotics:

These drugs depress the CNS activity, leading to relaxation, sleep induction, or sedation. Examples include benzodiazepines, barbiturates, and some antihistamines.

2. Cardiovascular Drugs:

These drugs act on the heart or blood vessels to treat conditions related to the cardiovascular system. They include:

a Antiarrhythmics:

These drugs are used to regulate abnormal heart rhythms. They are classified into different classes based on their mechanism of action

b) Analgesics:

These drugs are used to relieve pain and can act on the CNS. They include opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and local anesthetics

c) Sedatives and Hypnotics:

These drugs depress the CNS activity, leading to relaxation, sleep induction, or sedation. Examples include benzodiazepines, barbiturates, and some antihistamines

3. Cardiovascular Drugs: 

These drugs act on the heart or blood vessels to treat conditions related to the cardiovascular system. They can include:

a) Antiarrhythmics:

These drugs are used to regulate abnormal heart rhythms. They are classified into different classes based on their mechanism of action

b) Antihypertensives:

These drugs help lower blood pressure and can include various classes such as beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and diuretics.

c) Vasodilators:

These drugs relax and widen blood vessels, improving blood flow. Nitroglycerin and calcium channel blockers are examples of vasodilators.

4. Gastrointestinal Drugs:

These drugs primarily target the digestive system and include:

a. Antacids:

These drugs neutralize stomach acid and are used to relieve heartburn and indigestion

b. Antiemetics:

These drugs prevent or relieve nausea and vomiting. They can be used to treat motion sickness, chemotherapy-induced nausea, and other conditions.

c. Laxatives:

These drugs promote bowel movements and relieve constipation

5. Respiratory Drugs:

These drugs are used to treat conditions affecting the respiratory system, including:

a. Bronchodilators:

These drugs relax the smooth muscles of the airways, helping to widen them and improve airflow. They are commonly used in the treatment of asthma and chronic obstructive pulmonary disease (COPD).

b. Corticosteroids:

These drugs have anti-inflammatory effects and are used to manage chronic respiratory conditions such as asthma

c. Antitussives:

These drugs suppress or relieve coughing

Therapeutic Classification of Drugs

Drugs can be classified based on their therapeutic use or the medical conditions they are primarily used to treat. Here are some common therapeutic classifications of drugs

 1.   Analgesics: 

     These drugs are used to relieve pain. They can be further classified into opioid analgesics (e.g., morphine, oxycodone) and non-opioid analgesics such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and acetaminophen.

    2.   Antibiotics: 

          These drugs are used to treat bacterial infections. They include various classes such as penicillins, cephalosporins, macrolides, and fluoroquinolones.

    3.   Antidepressants: 

        These drugs are used to treat depression and other mood disorders. They can be categorized into selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs).

    4.   Antihypertensives: 

            These drugs are used to lower high blood pressure. They include classes such as angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, calcium channel blockers, and diuretics.

    5.   Antidiabetic drugs: 

                These drugs are used to manage diabetes mellitus. They include insulin (used in type 1 diabetes) and various classes of oral hypoglycemic agents such as biguanides, sulfonylureas, and dipeptidyl peptidase-4 (DPP-4) inhibitors.

    6.   Anticoagulants: 

            These drugs are used to prevent or treat blood clot formation. They include warfarin, heparin, and newer oral anticoagulants such as rivaroxaban and apixaban.

    7.   Antipsychotics: 

            These drugs are used to manage psychotic disorders such as schizophrenia. They can be classified as typical antipsychotics (first generation) and atypical antipsychotics (second generation).

    8.   Antiviral drugs: 

            These drugs are used to treat viral infections. Examples include antiretroviral drugs used in the treatment of HIV/AIDS, as well as drugs used to manage infections caused by herpes viruses, influenza viruses, and hepatitis viruses.

    9.   Antihistamines: 

            These drugs are used to treat allergies and allergic reactions. They can be classified as first-generation (e.g., diphenhydramine) or second-generation (e.g., loratadine), with differing sedative effects.

    10.      Anticonvulsants: 

        These drugs are used to manage seizures and epilepsy. Examples include phenytoin, carbamazepine, and valproic acid.

International Classification of Diseases

                The International Classification of Diseases (ICD) is a standardized system used worldwide for classifying and coding diseases, health conditions, and related factors. It provides a common language for reporting and analyzing health information. The current version of the classification is called ICD-10, which was endorsed by the World Health Organization (WHO) and implemented by many countries.

        ICD-10 organizes diseases and health conditions into chapters, each representing a broad category. Some of the chapters in ICD-10 include:

1. Certain infectious and parasitic diseases

2. Neoplasms (cancers)

3. Diseases of the blood and blood-forming organs

4. Endocrine, nutritional, and metabolic diseases

5. Mental and behavioral disorders

6. Diseases of the nervous system

7. Diseases of the eye

8. Diseases of the ear and mastoid process

9. Diseases of the circulatory system

10. Diseases of the respiratory system

11. Diseases of the digestive system

12. Diseases of the skin and subcutaneous tissue

13. Diseases of the musculoskeletal system and connective tissue

14. Diseases of the genitourinary system

15. Pregnancy, childbirth, and the puerperium

16. Certain conditions originating in the perinatal period

17. Congenital malformations, deformations, and chromosomal abnormalities

18. Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified

19. Injury, poisoning, and certain other consequences of external causes

20. External causes of morbidity and mortality

• 

       
        The WHO periodically updates the ICD to reflect advancements in medical knowledge and changes in healthcare practices. The next version, ICD-11, was released in 2018 and is gradually being implemented globally. ICD-11 incorporates improvements in terminology, usability, and coding structure compared to ICD-10.
    Here are some examples of conditions and diseases classified in the International Classification of Diseases (ICD-10) system

1. Certain infectious and parasitic diseases (Chapter I):

•   Malaria (Code: B54)
•   Tuberculosis (Code: A15-A19)
•   Influenza (Code: J10-J11)
•   HIV infection (Code: B20-B24)

2. Neoplasms (Chapter II):

•    Malignant neoplasm of breast (Code: C50)
•    Colorectal cancer (Code: C18-C21)
•    Lung cancer (Code: C34)
•    Prostate cancer (Code: C61)

3. Diseases of the circulatory system (Chapter IX):

•   Hypertension (Code: I10)
•   Coronary artery disease (Code: I25)
•   Stroke (Code: I63)
•   Heart failure (Code: I50)

4. Mental and behavioral disorders (Chapter V):

•   Major depressive disorder (Code: F32)
•   Schizophrenia (Code: F20)
•   Anxiety disorders (Code: F40-F41)
•    Bipolar disorder (Code: F31)

5. Diseases of the musculoskeletal system and connective tissue (Chapter XIII):

•     Osteoarthritis (Code: M15-M19)
•     Rheumatoid arthritis (Code: M05-M06)
•     Osteoporosis (Code: M81)
•     Fibromyalgia (Code: M79.7)

6. Diseases of the respiratory system (Chapter X):

•     Asthma (Code: J45)
•     Chronic obstructive pulmonary disease (COPD) (Code: J44)
•     Pneumonia (Code: J12-J18)
•     Lung cancer (Code: C34)

7. Diseases of the digestive system (Chapter XI):

•    Gastric ulcer (Code: K25)
•    Gallstones (Code: K80)
•    Crohn's disease (Code: K50)
•     Hepatitis (Code: B15-B19)

8. Diseases of the genitourinary system (Chapter XIV):

•     Chronic kidney disease (Code: N18)
•     Urinary tract infection (Code: N39)
•     Prostate enlargement (Code: N40)
•     Endometriosis (Code: N80)

9. Pregnancy, childbirth, and the puerperium (Chapter XV):

•     Preterm labor (Code: O60-O64)
•     Gestational diabetes mellitus (Code: O24)
•     Postpartum depression (Code: F53)
•     Maternal hypertension (Code: O10-O16)

10. Injury, poisoning, and certain consequences of external causes (Chapter XIX):

•     Fracture of the wrist (Code: S52)
•     Head injury (Code: S06)
•     Poisoning by drugs or medications (Code: T36-T50)
•     Burns (Code: T20-T32)

Daily Defined Doses

        Daily Defined Dose (DDD) is a measurement unit used in pharmacology and pharmacoepidemiology to standardize the prescribed daily dose of a medication. The World Health Organization (WHO) developed the concept of DDDs to allow for comparisons and analysis of drug utilization patterns across different populations and healthcare settings.

        The DDD represents the assumed average maintenance dose per day for a specific medication in adults for its main indication. It is expressed in terms of the drug's active ingredient. DDDs are not intended to be a recommended or prescribed dose but serve as a standardized unit for research and comparative purposes.

        The DDD is typically determined through expert consensus based on available clinical data and therapeutic guidelines. It may vary for different formulations, routes of administration, or patient populations.

        The International Nonproprietary Names (INN) system, established by the World Health Organization (WHO), provides unique and universally recognized generic names for pharmaceutical substances. The INN system helps to ensure clarity, accuracy, and consistency in the identification of drugs across different countries and languages. Here are a few examples of drugs and their INN

    1. Paracetamol: 

        INN for the active ingredient used in many over-the-counter pain relievers, known as acetaminophen in the United States.

    2. Ibuprofen: 

        INN for a nonsteroidal anti-inflammatory drug (NSAID) commonly used to relieve pain, reduce inflammation, and lower fever.

    3. Metformin: 

            INN for an oral antidiabetic medication used to manage type 2 diabetes.

    4. Sertraline: 

        INN for an antidepressant medication belonging to the selective serotonin reuptake inhibitor (SSRI) class.

    5. Atorvastatin: 

        INN for a statin medication used to lower cholesterol levels in the management of cardiovascular diseases.

    6. Omeprazole:

        INN for a proton pump inhibitor (PPI) used to reduce gastric acid secretion and treat conditions such as gastroesophageal reflux disease (GERD) and peptic ulcers.

    7. Metoprolol: 

            INN for a beta-blocker medication used to treat hypertension, angina, and certain heart conditions.

    8. Amoxicillin: 

            INN for a broad-spectrum antibiotic belonging to the penicillin class.

    9. Ciprofloxacin: 

            INN for an antibiotic in the fluoroquinolone class, commonly used to treat various bacterial infections.

    10. Simvastatin: 

        INN for a statin medication prescribed for reducing cholesterol levels and managing cardiovascular diseases.