Cholecalciferol Cholecalciferol (vitamin D₃) is a fat‑soluble secosteroid used to correct or prevent vitamin D deficiency and to provide therapeutic dosing in selected bone disorders. Mechanism of Action Active Metabolite Formation 1. Hepatic 25‑hydroxylation → 25‑hydroxycholecalciferol (calcidiol) 2. Renal 1α‑hydroxylation → 1,25‑dihydroxycholecalciferol (calcitriol), the biologically active form Receptor Binding – Binds to intracellular vitamin D receptor (VDR) in … Read more
Chlorthalidone Chlorthalidone is a thiazide‑like diuretic widely used for hypertension and edema. It excels in patient adherence due to its long half‑life and once‑daily dosing. — Mechanism of Action Inhibition of sodium‑chloride cotransporter (Na⁺/Cl⁻) in the distal convoluted tubule ↓ Na⁺ reabsorption → ↑ Na⁺ & water excretion Resultant natriuresis and diuresis Reduced intravascular volume … Read more
Chlorpheniramine Chlorpheniramine (Trade names: Chlor-Trimeton®, Chlorphen) is a first‑generation, centrally-acting antihistamine that blocks peripheral histamine H₁ receptors and possesses modest anticholinergic activity. — Mechanism of Action H₁ receptor antagonism: Competitively blocks peripheral and central H₁ receptors, reducing vasodilation, capillary permeability, and smooth‑muscle contraction. Anticholinergic effect: Inhibits muscarinic (M₁–M₄) receptors, contributing to sedation, xerostomia, and anticholinergic … Read more
Cetirizine Cetirizine is a second‑generation, selective H1‑histamine receptor antagonist widely used for allergic disorders. It offers potent antihistamine activity with minimal sedation and a favorable safety profile. Mechanism of Action Cetirizine competitively binds the H1 receptor at the same site as histamine, preventing histamine‑mediated vasodilation, increased vascular permeability, and nerve stimulation. It exhibits high affinity … Read more
Cequa Cequa is the branded, 10 mg chewable tablet of the second‑generation antihistamine cetirizine. It is widely prescribed for seasonal allergic rhinitis and chronic urticaria due to its rapid onset, minimal sedation, and once‑daily dosing. Mechanism of Action Selective H1‑receptor antagonist: Cetirizine binds to peripheral and central H1 histamine receptors, competitively inhibiting histamine release from mast … Read more
Cephalexin Cephalexin is a first‑generation cephalosporin antibiotic. It is widely used for uncomplicated skin and soft‑tissue infections, urinary tract infections, and respiratory tract infections. The drug offers broad coverage against gram‑positive organisms and some gram‑negative rods, with a favorable safety profile for outpatient use. Mechanism of Action Inhibits bacterial cell‑wall synthesis by binding to penicillin‑binding … Read more
Celexa Celexa (citalopram) is a selective serotonin reuptake inhibitor (SSRI) widely used for major depressive disorder, panic disorder, and other anxiety conditions. Mechanism of Action Selective serotonin reuptake inhibition: Inhibits the presynaptic serotonin transporter (SERT) with high affinity, enhancing extracellular serotonin levels primarily in the CNS. Improves serotonergic neurotransmission, contributing to mood elevation and anxiolysis. … Read more
Celecoxib Mechanism of Action Celecoxib is a selective cyclo‑oxygenase‑2 (COX‑2) inhibitor that attenuates the synthesis of pro‑inflammatory prostaglandins (PGE2, PGI2, and PGF2α) by competitively binding to the COX‑2 enzyme’s catalytic site. Reduced edema and pain by limiting prostaglandin‑mediated nociceptor sensitization. Preserves COX‑1 activity, thereby minimizing gastrointestinal prostaglandin‑mediated mucosal protection and platelet aggregation. Pharmacokinetics Absorption: Oral … Read more
Celebrex Celebrex (celecoxib) is a selective cyclo‑oxygenase‑2 (COX‑2) inhibitor used primarily for pain and inflammation in arthritis and other musculoskeletal conditions. Mechanism of Action Selective COX‑2 inhibition: Reduces prostaglandin E₂ synthesis, decreasing inflammation and pain. Reduced gastric prostaglandin: Preservation of COX‑1 activity limits gastrointestinal (GI) mucosal injury compared with non‑selective NSAIDs. Modest anti‑inflammatory profile: Lower … Read more
Cefuroxime A second‑generation cephalosporin with broad gram‑positive and select gram‑negative activity, commonly used for community‑acquired bacterial infections. Mechanism of Action Cefuroxime competitively inhibits bacterial transpeptidase (penicillin‑binding proteins), disrupting peptidoglycan cross‑linking in the cell wall. Result: loss of structural integrity → bacterial lysis, especially in actively dividing organisms. Sub‑typical Gram‑negative coverage: Haemophilus influenzae, Streptococcus pneumoniae, and … Read more