PharmD Notes - Pharmacy Freak

Mechanism of Action of Amantadine

April 10, 2026July 3, 2025 Pharmacy Freak Editorial Team Harsh Singh Rajput

Introduction Amantadine is an antiviral agent and antiparkinsonian medication. Initially used for influenza A, it also treats drug-induced extrapyramidal symptoms and Parkinson’s disease. Its mechanism combines viral M2 ion channel inhibition and enhancement of dopaminergic neurotransmission in the central nervous system. Step-by-Step Mechanism of Action Pharmacokinetic Parameters Parameter Value Route Oral (capsule, syrup) Bioavailability ~86% … Read more

Mechanism of Action of Apremilast (Otezla)

April 10, 2026July 3, 2025 Pharmacy Freak Editorial Team Harsh Singh Rajput

Introduction Apremilast (Otezla) is an oral phosphodiesterase-4 (PDE4) inhibitor approved for psoriasis, psoriatic arthritis, and Behçet’s disease‑associated oral ulcers. By modulating intracellular signaling, it reduces inflammation and disease symptoms through balanced cytokine regulation. Step-by-Step Mechanism of Action Pharmacokinetic Parameters Parameter Value Route Oral (delayed-release tablet) Bioavailability ~73% Time to Peak (Tmax) ~2–4 hours Protein Binding … Read more

Mechanism of Action of Wellbutrin (Bupropion)

April 10, 2026July 2, 2025 Pharmacy Freak Editorial Team Harsh Singh Rajput

Introduction Wellbutrin (bupropion) is an atypical antidepressant and smoking cessation aid. It primarily works by inhibiting reuptake of norepinephrine and dopamine, without affecting serotonin. Additionally, it acts as a nicotinic receptor antagonist, reducing nicotine cravings. Step-by-Step Mechanism of Action Pharmacokinetic Parameters Parameter Value Route Oral (IR, SR, XL formulations) Bioavailability ~5–20% Time to Peak (Tmax) … Read more

Mechanism of Action of Januvia (Sitagliptin)

April 10, 2026July 2, 2025 Pharmacy Freak Editorial Team Harsh Singh Rajput

Introduction Januvia (sitagliptin) is an oral dipeptidyl peptidase‑4 (DPP‑4) inhibitor used to improve glycemic control in type 2 diabetes mellitus (T2DM). It enhances incretin levels, thereby increasing insulin secretion and lowering glucagon in a glucose-dependent manner. Step-by-Step Mechanism of Action Pharmacokinetic Parameters Parameter Value Route Oral (tablet) Bioavailability ~87% Time to Peak (Tmax) ~1–4 hours Protein … Read more

Mechanism of Action of Stelara (Ustekinumab)

April 10, 2026July 2, 2025 Pharmacy Freak Editorial Team Harsh Singh Rajput

Introduction Stelara (ustekinumab) is a fully human IgG1κ monoclonal antibody designed to target key cytokines involved in immune-mediated diseases. It selectively binds to the p40 subunit common to interleukin-12 (IL-12) and interleukin-23 (IL-23), blocking their interaction with cell surface receptors. Stelara is approved for several chronic inflammatory conditions including plaque psoriasis, psoriatic arthritis, Crohn’s disease, … Read more