Mechanisms of action Magnesium Hydroxide

Mechanisms of action

• Antacid (magnesium hydroxide, magnesium oxide): neutralizes or reduces gastric acidity, resulting in an increase in the pH of the stomach and duodenal bulb and inhibition of the proteolytic activity of pepsin.
• Laxative (magnesium citrate, magnesium hydroxide): attracts/retains water in intestinal lumen and distends bowel; causes the duodenal secretion of cholecystokinin, which stimulates fluid secretion and intestinal motility.

Indications

• Symptomatic relief of upset stomach associated with hyperacidity
• Hyperacidity associated with peptic ulcer, gastritis, peptic esophagitis, gastric hyperacidity, and hiatal hernia
• Prophylaxis of GI bleeding, stress ulcers, aspiration pneumonia
• Short-term relief of constipation; evacuation of the colon for rectal and bowel examination

Contraindications/cautions

• Contraindicated in the presence of allergy to magnesium products.
• Use caution in the presence of renal insufficiency.

Adverse effects

• CNS: Dizziness, fainting, sweating
• GI: Diarrhea, nausea, perianal irritation
• Metabolic: Hypermagnesemia and toxicity in renal failure patients

Mechanism of action of aluminum carbonate gel

Mechanism of action of aluminum carbonate gel

Neutralizes or reduces gastric acidity, resulting in an increase in the pH of the stomach and duodenal bulb and inhibiting the proteolytic activity of pepsin, which protects the lining of the stomach and duodenum; binds with phosphate ions in the intestine to form insoluble aluminum-phosphate complexes, lowering phosphate in hyperphosphatemia and chronic renal failure but may cause hypophosphatemia in other states.

Indications

1. Symptomatic relief of upset stomach associated with hyperacidity
2. Hyperacidity associated with peptic ulcer, gastritis, peptic esophagitis, gastric hyperacidity, hiatal hernia
3. Treatment, control, or management of hyperphosphatemia-aluminum carbonate
4. Prevention of formation of phosphate urinary stones, used in conjunction with a low-phosphate diet-aluminum carbonate
5. Unlabeled use for aluminum hydroxide: prophylaxis of GI bleeding, stress ulcer; reduction of phosphate absorption in hyperphosphatemia in patients with chronic renal failure

Contraindications/cautions

• Allergy to aluminum products
• Gastric outlet destruction
• Hypertension
• CHF
• Hypophosphatemia
• Lactation

Adverse effects of aluminum carbonate gel

• GI: Constipation; intestinal obstruction, decreased absorption of fluoride, accumulation of aluminum in serum, bone, and CNS
• MS: Osteomalacia and chronic phosphate deficiency with bone pain, malaise, muscular weakness

Mechanism of action of Acetaminophen

Mechanism of action of Acetaminophen
Inhibits the synthesis of prostaglandins in the central nervous system and peripherally blocks pain impulse generation; produces antipyresis from inhibition of hypothalamic heat-regulating center.

Indications of Acetaminophen

1. Analgesic-antipyretic in patients with aspirin allergy, hemostatic disturbances, bleeding diatheses, upper GI disease, gouty arthritis
2. Arthritis and rheumatic disorders involving musculoskeletal pain (but lacks clinically significant antirheumatic and anti- inflammatory effects)
3. Common cold, "flu," other viral and bacterial infections accompanied by pain and fever
4. Unlabeled use: prophylactic for children receiving DPT vaccination to reduce incidence of fever and pain

Contraindications of Acetaminophen

1. Contraindicated in the presence of allergy to acetaminophen.
2. Use caution in the presence of impaired hepatic function, chronic alcoholism, pregnancy, lactation.

Mechanism of action of ibuprofen

Mechanism of action
Anti-inflammatory, analgesic, and antipyretic activities largely related to inhibition of prostaglandin synthesis; exact mechanisms of action are not known.

Indications

1. Relief of signs and symptoms of rheumatoid arthritis and osteoarthritis
2. Relief of mild to moderate pain
   Treatment of primary dysmenorrhea
3. Fever reduction
4. Unlabeled use: treatment of juvenile rheumatoid arthritis

Contraindications

1. Presence of allergy to ibuprofen, salicylates, or other NSAIDs (more common in patients with rhinitis, asthma, chronic urticaria, nasal polyps)
2. Cardiovascular dysfunction
3. Hypertension
4. Peptic ulceration
5. GI bleeding
6. Pregnancy
7. Lactation

Use caution in the presence of impaired hepatic or renal function.

Mechanism of action of Diclofenac

Mechanism of action of Diclofenac
Inhibits prostaglandin synthetase to cause antipyretic and anti-inflammatory effects; the exact mechanism of action is not known.

Indications of Diclofenac

1. Acute or long-term treatment of mild to moderate pain, including dysmenorrhea
2. Rheumatoid arthritis
3. Osteoarthritis
4. Ankylating spondylitis

Contraindications of Diclofenac

1. Contraindicated in the presence of significant renal impairment, pregnancy, lactation.
2. Use caution in the presence of impaired hearing, allergies, hepatic,
   cardiovascular, and GI conditions.

Adverse effects of Diclofenac

• CNS: Headache, dizziness, somnolence, insomnia, fatigue, tiredness, dizziness, tinnitus, ophthamologic effects
• GI: Nausea, dyspepsia, GI pain, vomiting, constipation, flatulence
• Hematologic: Bleeding, platelet inhibition with higher doses
• GU: Dysuria, renal impairment
• Dermatologic: Rash, pruritus, sweating, dry mucous membranes, stomatitis
• Other: Peripheral edema, anaphylactoid reactions to fatal anaphylactic shock

Mechanism of action of Aspirin

Mechanism of action of Aspirin
Analgesic and antirheumatic effects are attributable to aspirin's ability to inhibit the synthesis of prostaglandins, important mediators of inflammation. Antipyretic effects are not fully understood, but aspirin probably acts in the thermoregulatory center of the hypothalamus to block effects of endogenous pyrogen by inhibiting synthesis of the prostaglandin intermediary. Inhibition of platelet aggregation is attributable to the inhibition of platelet synthesis of thromboxane A2, a potent vasoconstrictor and inducer of platelet aggregation.

This effect occurs at low doses and lasts for the life of the platelet (8
d). Higher doses inhibit the synthesis of prostacyclin, a potent
vasodilator and inhibitor of platelet aggregation.

Indications of Aspirin

1. Mild to moderate pain
2. Fever
3. Inflammatory conditions-rheumatic fever, rheumatoid arthritis,
   osteoarthritis
4. Reduction of risk of recurrent TIAs or stroke in males with history of
   TIA due to fibrin platelet emboli
5. Reduction of risk of death or nonfatal MI in patients with history of
   infarction or unstable angina pectoris
6. Unlabeled use: prophylaxis against cataract formation with long-term use

Contraindications of Aspirin

1. Allergy to salicylates or NSAIDs (more common in patients with nasal polyps, asthma, chronic urticaria);
2. allergy to tartrazine (cross-sensitivity to aspirin is common);
3. hemophilia, bleeding ulcers, hemmorhagic states, blood coagulation defects, hypoprothrombinemia, vitamin K deficiency (increased risk of bleeding);
4. impaired or renal function;
5. chickenpox, influenza (potential risk of Reye's syndrome in children and teenagers); children with fever accompanied by dehydration;
6. surgery scheduled within 1 wk; pregnancy (maternal anemia, antepartal and postpartal hemorrhage, prolonged gestation, and prolonged labor have been reported; readily crosses the placenta; possibly teratogenic; maternal ingestion of aspirin during late pregnancy has been associated with the following adverse fetal effects: low birth weight, increased intracranial hemorrhage, stillbirths, neonatal death);
7. lactation.

Adverse effects of Aspirin

• GI: Nausea, dyspepsia, heartburn, epigastric discomfort, anorexia, hepatotoxicity
• Hematologic: Occult blood loss, hemostatic defects
• Hypersensitivity: Anaphylactoid reactions to fatal anaphylactic shock
• Aspirin intolerance: Exacerbation of bronchospasm, rhinitis (in patients with nasal polyps, asthma, rhinitis)
• Salicylism: Dizziness, tinnitus, difficulty hearing, nausea, vomiting, mental confusion, lassitude (dose related)
• Acute aspirin toxicity: Respiratory alkalosis, hyperpnea, tachypnea, hemorrhage, excitement, confusion, asterixis, pulmonary edema, convulsions, tetany, metabolic acidosis, fever, coma, cardiovascular collapse, renal and respiratory failure (dose related 20-25 g in adults, 4 g in children).

Name: Propoxyphene hydrochloride

Therapeutic actions

Acts as agonist at specific opioid receptors in the CNS to produce analgesia, euphoria, sedation; the receptors mediating these effects are thought to be the same as those mediating the effects of endogenous opioids (enkephalins, endorphins).

Indications

Relief of mild to moderate pain

Contraindications/cautions

Contraindicated in the presence of hypersensitivity to narcotics, pregnancy (neonatal withdrawal has occurred in infants born to mothers who used narcotics during pregnancy; safety for use in pregnancy not
established), labor or delivery (especially when delivery of a premature
infant is expected; administration of narcotics to the mother can cause
respiratory depression of neonate; may prolong labor), lactation.

Use caution in the presence of renal or hepatic dysfunction, emotional depression.

Adverse effects

• CNS: Dizziness, sedation, lightheadedness, headache, weakness, euphoria, dysphoria, minor visual disturbances
• GI: Nausea, vomiting, constipation, abdominal pain, liver dysfunction
• Dermatologic: Skin rashes
• Other: Tolerance and dependence, psychological dependence