Stimulant Laxatives Classification

Laxatives

• Stimulant laxatives stimulate peristaltic action and can be dangerous under certain circumstances
• They are the most powerful among laxatives and should be used with care, as they can be very habit-forming
• Examples of stimulant laxatives include:
  • Cascara (casanthranol)
  • Senna extract (senna glycoside)
  • Aloe vera (aloin)
  • Bisacodyl (oral) (dulcolax)
  • Castor oil (ricinoleic acid)

Stool Softeners (Lubricant Laxatives)

• Make the stool slippery, so it slides through the intestine more easily
• Examples include mineral oil, which also retards colonic absorption of water, softening the stool
• Mild laxative, good for pregnancy, lactation, and children

Antidiarrheal

• Diarrhea is the condition of having three or more loose or liquid bowel movements per day
• Common causes include:
  • Microorganisms (bacteria, virus, or ameba)
  • Drugs that stimulate the parasympathetic nervous system
  • Broad-spectrum antibiotics
  • Functional simple diarrhea, poor dietary habits, and stress
• Diarrhea can cause dehydration and electrolyte disturbances, such as potassium deficiency or other salt imbalances

Bronchial Asthma

• A common chronic inflammatory disease of the airways
• Characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm
• Common symptoms include:
  • Wheezing
  • Coughing
  • Chest tightness
  • Shortness of breath
• Asthma can be prevented by avoiding triggers, such as allergens and irritants (infections, exercise, various allergens, and psychological factors)

Pathophysiology of Asthma

• Chronic inflammation of the airways, edema of bronchial mucosa
• Increased contractibility of the surrounding smooth muscle, leading to bouts of narrowing of the airway and classic symptoms

Treatment of Asthma

• Correct use of drugs, either given regularly to prevent an attack or intermittently to relieve one
• Bronchodilators, such as beta2-adrenoceptor agonists (β2 agonists), are the first line of treatment for asthma symptoms
• Examples of bronchodilators include salbutamol (ventolin)®

Hematinics

• Vitamins or minerals that are essential for normal erythropoiesis
• Examples include:
  • Iron compounds
  • Vitamin B12
  • Folic acid

Iron Compounds

• Physiological importance:
  • Present in hemoglobin (70% of body iron)
  • Present in mioglobin (5% of body iron)
  • Present in enzymes (cytocrome 0.2%)
  • Stored in reticuloendothelial system and bone marrow as ferritin and hemosederin (25%)
  • 2% lies in the labile iron pool (part of body iron which is readily available)
• Pharmacokinetics:
  • Absorbed from the small intestine (10%); the amount absorbed increases in anemia
  • Ferrous Fe++ is better absorbed than ferric Fe+++
  • Food impairs absorption, and vitamin C enhances it
  • Pregnant women need 5 mg daily during the third trimester
• Uses:
  • Iron deficiency anemia resulting from:
    • Excess demand
    • Reduced stores
    • Defective absorption
• Side effects:
  • Nausea
  • Epigastric pain
  • Constipation

Vitamin B12

• Physiological importance:
  • Required for normal erythropoiesis and maturation of other cell types
  • Required for certain biochemical reactions
  • Facilitates entrance of folic acid into the cell
• Pharmacokinetics:
  • Normal body store is 3 mg
  • Synthesized in the small intestine by normal flora (5 mg/day)
  • The absorption needs the presence of intrinsic factor
• Uses:
  • Used in pernicious anemia resulting from:
    • Deficiency of intrinsic factor (genetic)
    • Nutritional deficiency
    • Mal-absorption
  • Can be given orally or by injection in a dose of 300-1000 mg/day

Folic Acid

• Present in a wide variety of plants and animal tissues
• Required for normal erythropoiesis and many biochemical reactions
• Deficiencies lead to megaloblastic anemia
• Uses:
  • Folate deficiency resulting from:
    • Nutritional deficiency (children, old age, alcoholism)
    • Mal-absorption (diseases of the small intestine)
    • Excessive utilization (pregnancy, hemolytic anemia, malignant diseases, chronic inflammatory diseases)
    • Drugs such as phenytoin, phenobarbitone, nitrofurantoin

Astringents

• Locally applied protein precipitants, causing contraction of tissues and wrinkling of tissues
• Examples include:
  • Calamine
  • Alum
  • Zinc oxide
  • Tannic acid

Counter Irritants, Rubifacient

• Topically applied analgesics, applied to intact skin
• Cause feeling of hotness and burning, masking the pain
• Examples include:
  • Camphor
  • Black mustard
  • Salicylate
  • Turpentine oil
  • Menthol
  • Capsaicin
  • Eucalyptus oil

Protective and Absorbent

• Contain water-repellent substances and may be used to protect the skin
• May absorb moisture, and physical barrier preparations
• Examples include:
  • Talc
  • Zinc oxide
  • Dimethicone
  • Cotton
  • Cellulose
  • Bandage
  • Gauze
  • Plaster
  • Collodions

Caustics

• Topical agents that destroy the upper thick layer of skin
• Examples include:
  • Phenol
  • AgNO3
• Uses:
  • Destroy warts (viral infection causing raised thick layer over skin)
  • Keratosis
  • Fungal infections and eczema

Keratolytics

• Desquamating agents, causing desquamation of dermis, destroying unwanted tissue
• Great care is necessary to avoid ulceration
• Examples include:
  • Titanium dioxide

Psoriasis

• White silvery spots over skin, especially on extensor surfaces, knees, elbows, and scalp
• Due to rapid turnover of epidermis
• Management:
  • Moisturizers
  • Medicated creams and ointments
  • Ointments and creams containing coal tar, dithranol (anthralin), and corticosteroids
  • Activated vitamin D and its analogues

Eczema

• Also known as atopic dermatitis, a form of chronic inflammation of the skin
• Characterized by:
  • Redness
  • Skin edema (swelling)
  • Itching and dryness
  • Crusting
  • Flaking
  • Blistering
  • Cracking
  • Oozing
  • Bleeding
• Management:
  • Corticosteroids
  • Antihistamines
  • Moisturizers, as eczema can be exacerbated by dryness of the skin