Pharmacology of Diuretics and Opioid Antagonists

Diuretics

• Mannitol: Alters osmosis, reduces water volume and intracranial pressure (ICP).
• Indications: Cerebral oedema, increased ocular pressure.
• Risk: Fluid leaking back into interstitial spaces, potentially worsening cerebral oedema.
• Loop Diuretic (Frusemide): Blocks sodium reabsorption in the loop of Henle.
• Thiazide (Hydrochlorothiazide): Acts in the distal tubule, depletes potassium.
• K-Sparing (Spironolactone): Counteracts potassium loss.
• Indications: Hypertension, chronic renal failure.

Opioid Antagonist

• Naloxone: Blocks opioid effects at mu opioid receptors, prevents G protein coupling.
• Indications: Opioid overdose.
• Characteristics: Quick onset, short-acting; requires repeated dosing.

Anti-Seizure Medications

• Sodium Valproate (Epilim): Increases GABA, blocks sodium channels. Used for seizures, epilepsy, and mania.
• Phenobarbital (Barbital): Enhances GABA action, reduces seizure spread. Indicated for epilepsy and sedation.
• Phenytoin (Dilantin): Modulates sodium channels, stabilizing nerve excitability. Used in tonic-clonic seizures and post-surgery.
• Carbamazepine: Reduces nerve impulses, treats seizures, nerve pain, schizophrenia, and bipolar disorder.
• Gabapentin: Blocks nerve signals, treats seizures and nerve pain. Risk of dependence and suicidal thoughts.
• Lamotrigine: Modulates sodium channels, reduces glutamate release. Treats seizures, nerve pain, and bipolar disorder.

Dopamine Precursor and Decarboxylase Inhibitor

• Levodopa (Sinemet): Converts to dopamine in the brain, used for Parkinson's disease.
• Carbidopa: Inhibits peripheral conversion of levodopa.

Sedative

• Midazolam: Acts on GABA A receptors, calming the brain.
• Indications: Seizures, anesthesia.

Gastrointestinal (GIT)

• Histamine H2 Blockers (Ranitidine, Famotidine): H2 receptor antagonists inhibit gastric acid production.
• Indications: Gastric ulcers, heartburn, GERD.
• Anti-Diarrheal (Loperamide): Activates opioid receptors in the gut, reduces stool frequency.
• Indications: Diarrhea.
• Proton Pump Inhibitors (Pantoprazole): Suppresses gastric acid secretion.
• Indications: GI lesions, ulcers, GERD.
• Laxative (Lactulose): Prevents ammonia absorption, softens stools.
• Indications: Hepatic encephalopathy, stool softening.

Endocrine

• Insulin: Regulates glucose metabolism, lowers blood glucose levels (BGL).
  • Short-Acting: Actrapid, Novorapid
  • Long-Acting: Solostar, Optisulin
  • Indications: Type 1 and Type 2 diabetes mellitus (T1DM, T2DM).
• Biguanide (Metformin): Reduces liver glucose production, increases insulin sensitivity.
  • Indications: First-line treatment for T2DM.
• Sulfonylureas (Glipizide): Increases insulin secretion.
  • Indications: Adjunct for T2DM.
• SGLT2 Inhibitor (Dapagliflozin): Reduces glucose reabsorption in kidneys.
  • Indications: T2DM, weight loss, fluid management.

Renal

• Erythropoietin: Stimulates RBC production.
  • Indications: Anemia in chronic renal failure or cancer.
• Vitamin D: Increases calcium and phosphate absorption.
  • Indications: Vitamin D and calcium deficiency.
• Colloid (Albumin): Increases osmotic pressure, retains fluid intravascularly.
  • Indications: Fluid resuscitation, shock, rehydration.

Electrolytes and Fluids

• Electrolyte (Potassium): Maintains muscle and nerve function.
  • Indications: Potassium deficiency.
• Crystalloid Solutions (NS 0.9%, CSL, Dex5%): Match osmolarity of blood, no fluid shifts.
  • Indications: Fluid resuscitation, shock.
• Hypotonic Solutions (10% Dextrose, 50% Dextrose): Move water into cells.
  • Indications: Hyponatremia, cellular dehydration.
• Hypertonic Solutions (0.45% N/S): Move water out of cells.
  • Indications: Hypernatremia, reduce intracranial pressure.

This quiz covers essential pharmacology concepts related to diuretics, opioid antagonists, and anti-seizure medications. It focuses on the mechanisms of action, indications, and risks associated with these drugs. Test your knowledge on crucial medication management and related clinical applications.