JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D IV Year PHARMACOTHERAPEUTICS - III Previous Question Paper (April/May - 2019 - R08)

Parkinsonism is primarily characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta of the basal ganglia. This leads to a profound deficiency of dopamine in the striatum, which normally acts to modulate motor activity via the direct and indirect pathways.

Under physiological conditions, dopamine maintains a balance between excitatory cholinergic (acetylcholine) and inhibitory dopaminergic signaling. In Parkinsonism, the loss of inhibitory dopaminergic input results in an overactivity of cholinergic neurons. This imbalance leads to increased inhibitory output from the basal ganglia to the thalamus, which suppresses the motor cortex and manifests as the cardinal clinical features: bradykinesia, resting tremor, rigidity, and postural instability.

A critical molecular component is the accumulation of alpha-synuclein proteins, which aggregate to form Lewy bodies within the surviving neurons. These aggregates contribute to oxidative stress, mitochondrial dysfunction, and neuroinflammation, further accelerating neuronal cell death.

The therapeutic management of peptic ulcer disease (PUD) focuses on eradicating causative factors, primarily Helicobacter pylori infection and NSAID use, while promoting mucosal healing through acid suppression.

1. Eradication of H. pylori: The standard approach is triple therapy consisting of a proton pump inhibitor (PPI) (e.g., omeprazole or pantoprazole) combined with two antibiotics, typically clarithromycin and amoxicillin or metronidazole, for 10 to 14 days. Bismuth-based quadruple therapy is used in areas with high clarithromycin resistance.

2. Acid Suppression: PPIs are the drugs of choice as they provide superior acid inhibition compared to H2-receptor antagonists (e.g., ranitidine, famotidine). They facilitate ulcer healing by maintaining intragastric pH above 3 for extended periods.

3. Mucosal Protective Agents: Agents such as sucralfate, bismuth subsalicylate, or misoprostol may be used as adjuncts. Sucralfate forms a physical barrier over the ulcer crater, while misoprostol, a prostaglandin E1 analog, is particularly useful for preventing NSAID-induced ulcers by enhancing mucus and bicarbonate secretion.

4. Lifestyle Modifications: Patients are advised to discontinue NSAIDs, limit alcohol consumption, and cease smoking, as these factors impair mucosal defense and delay healing.