Essential Pharmacology: Drug Classes and Clinical Uses

Classification of Antifungal Drugs

Dose:

• For adults: 1 to 2 grams given every 8 hours (as directed by the healthcare provider).
• For children: 25 to 50 mg per kilogram of body weight per day, divided into 3 or 4 doses (as directed by the healthcare provider).

Indications:

• Skin and soft tissue infections
• Urinary tract infections
• Respiratory tract infections
• Bone and joint infections
• Endocarditis

Contraindications:

• Diarrhea
• Nausea
• Vomiting
• Indigestion

Aminoglycosides

Aminoglycosides are a class of antibiotics derived from Streptomyces bacteria. Amikin (amikacin) is an aminoglycoside antibiotic used to treat serious bacterial infections.

Classification of Aminoglycosides

1. Systemic: Streptomycin, Amikacin, Gentamicin, Kanamycin, Netilmicin, Tobramycin, Sisomicin.
2. Topical: Neomycin, Framycetin.

Streptomycin

Streptomycin belongs to the aminoglycoside class. It works by killing the organisms that cause infection. This drug may also be used to treat other serious infections such as Mycobacterium avium complex (MAC), tularemia, endocarditis, and plague, along with other medications.

Indications: Tuberculosis, Tularemia, Plague.

Contraindications: Hypersensitivity, neuromuscular disorders, renal impairment, pregnancy, and breastfeeding.

Anti-Tubercular Drugs

Anti-tubercular drugs are a group of medications used in the treatment of tuberculosis (TB), a bacterial infection caused by Mycobacterium tuberculosis.

Classification of Anti-Tubercular Drugs

1. First-line drugs: Isoniazid, Rifampin, Ethambutol, Pyrazinamide.
2. Second-line drugs: Streptomycin, Kanamycin, Capreomycin, Amikacin.
3. Other drugs: Bedaquiline, Delamanid, Linezolid.

Dosage and Indications

1. Isoniazid (INH):

• Adult dose: 5 mg/kg to 15 mg/kg of body weight, up to a maximum of 300 mg per day.
• Pediatric dose: 10 mg/kg to 20 mg/kg of body weight, up to a maximum of 300 mg per day.

Indications of anti-tubercular drugs: Tuberculosis, Gaucher's disease, Mycobacterium avium.

Contraindications: Diarrhea, nausea, vomiting.

Biologics and Hormonal Products

Infectious diseases: Vaccines such as the HPV vaccine and influenza vaccine are used to prevent the spread of respective diseases. Monoclonal antibodies such as infliximab (Remicade) are used to treat viral infections such as hepatitis B and C.

Hormonal deficiencies: Recombinant DNA products such as human growth hormone (HGH) are used to treat growth hormone deficiency. Insulin is used to treat diabetes.

Sulfonamides (Sulfa Drugs)

Sulfonamides are a class of antibiotics that target bacteria causing infections.

Classification of Sulfonamides

1. Short-acting: Sulfisoxazole, Sulfamethoxazole, Sulfadiazine.
2. Intermediate-acting: Sulfadimidine, Sulfamethazine, Sulfamoxole.
3. Long-acting: Sulfadoxine, Sulfamethoxypyridazine, Sulfasalazine.
4. Topical: Silver sulfadiazine, Mafenide.

Dose (Short-acting): Sulfisoxazole: 500-1000 mg orally 2-4 times daily.

Indications: Urinary tract infections (UTIs), malaria, toxoplasmosis, rheumatoid arthritis, otitis media, acute exacerbations of chronic bronchitis, and diarrhea.

Contraindication: Allergy.

Corticosteroids

Corticosteroids are hormones produced naturally by the adrenal cortex, playing an important role in maintaining normal body functions. They are also available in synthetic form for therapeutic use.

Physiological and Pathological Roles

• Physiological roles: Corticosteroids help regulate the metabolism of carbohydrates, fats, and proteins. They regulate the stress response by increasing blood sugar levels and blood pressure while suppressing the immune response.
• Pathological roles: Used for inflammatory disorders such as rheumatoid arthritis, asthma, and autoimmune disorders. They help reduce inflammation, swelling, and pain. They also treat allergic reactions, reducing symptoms like itching and hives.

Antidiuretics

Antidiuretics inhibit water excretion without affecting salt excretion.

Classification of Antidiuretic Drugs

Desmopressin

Desmopressin is used to control excessive thirst and the passage of abnormally large amounts of urine following head injuries or surgery.

• Pharmacological Action: Binds to V2 receptors in the basolateral membrane of the distal tubule and collecting ducts, stimulating adenylyl cyclase.
• Indications: Polyuria, primary nocturnal enuresis, nocturia, diabetes insipidus, Hemophilia, and Von Willebrand's Disease (Type I).
• Contraindications: Renal disease and cardiac insufficiency.

Vasopressin

Vasopressin (antidiuretic hormone or ADH) is a nonapeptide hormone produced in the hypothalamus. It affects diuresis, hemodynamics, and behavior.

• Pharmacological Action: Increases blood pressure via vasoconstriction; enhances renal fluid reuptake via V1 and V2 receptors.
• Indication: Used to increase blood pressure in adults with vasodilatory shock refractory to fluids.
• Contraindication: Hypersensitivity, vascular disease, especially coronary artery disease.

Vitamin D and Estrogen

Vitamin D

Deficiency can lead to rickets in children and osteomalacia in adults. Low levels are linked to increased risks of falls and fractures.

Clinical Uses: Prescribed for those with limited sun exposure, older adults, or those with absorption issues. Also used to treat osteoporosis.

Estrogen

Produced mainly by the ovaries (women) and testes (men).

• Physiological roles: Development of female reproductive organs (uterus, fallopian tubes, vagina), cardiovascular protection, and cognitive function.
• Pathological effects: High levels may promote breast cancer, endometrial cancer, and blood clots (DVT or pulmonary embolism).
• Clinical uses: Hormone replacement therapy (HRT) for menopause symptoms and contraception (in combination with progestin).

Classification of Anti-Neoplastic Agents

1. Alkylating Agents: Altretamine, Bendamustine, Busulfan, Carmustine, Chlorambucil, Cyclophosphamide, Dacarbazine, Ifosfamide, Trabectedin.
2. Platinum Coordination Complexes: Carboplatin, Cisplatin.
3. Cytotoxic Antibiotics: Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin.
4. Antimetabolites:
   • Antifolates: Methotrexate, Pemetrexed, Pralatrexate, Trimetrexate.
   • Purine Analogues: Azathioprine, Cladribine, Fludarabine, Mercaptopurine, Thioguanine.
   • Pyrimidine Analogues: Azacitidine, Capecitabine, Cytarabine.
5. Biologic Response Modifiers: Aldesleukin (IL-2), Denileukin Diftitox.
6. Histone Deacetylase Inhibitors: Belinostat, Panobinostat, Romidepsin, Vorinostat.
7. Hormonal Agents:
   • Antiandrogens: Abiraterone, Apalutamide, Bicalutamide, Cyproterone, Enzalutamide.
   • Antiestrogens/Aromatase Inhibitors: Anastrozole, Exemestane, Fulvestrant, Letrozole, Raloxifene, Tamoxifen, Toremifene.
   • GnRH Analogues: Degarelix, Goserelin, Histrelin, Leuprolide, Triptorelin.
   • Peptide Hormones: Lanreotide, Octreotide, Pasireotide.
8. Monoclonal Antibodies: Alemtuzumab, Tremelimumab.
9. Protein Kinase Inhibitors: Abemaciclib, Acalabrutinib, Afatinib, Alectinib, Alpelisib, Axitinib, Ruxolitinib.
10. Taxanes: Cabazitaxel, Docetaxel, Paclitaxel.
11. Topoisomerase Inhibitors: Etoposide, Irinotecan, Teniposide, Topotecan.
12. Vinca Alkaloids: Vinblastine, Vincristine, Vinorelbine.
13. Miscellaneous: Asparaginase (Pegaspargase), Bexarotene, Eribulin, Everolimus.

Diuretics and Myasthenia Gravis

Classification of Diuretics

The goal of treatment for conditions like Myasthenia Gravis is to increase muscle function and prevent swallowing or breathing problems. Most patients can lead near-normal lives with proper management.

Treatment Options

• Medicine: Anticholinesterase medicines, steroids, or immunosuppressive drugs.
• Thymectomy: Surgical removal of the thymus gland; reduces symptoms in over 70% of non-cancerous cases.
• Plasmapheresis: Removes abnormal antibodies from the blood and replaces them with normal ones.
• Immunoglobulin: A blood product given intravenously (IV) to decrease the immune system's attack on the nervous system.