Levodopa can cause

Correct Answer: D

Rationale: The correct answer is D: On-Off phenomenon. Levodopa is a medication used to treat Parkinson's disease by increasing dopamine levels in the brain. The On-Off phenomenon refers to the fluctuation between periods of good symptom control (On) and poor symptom control (Off) experienced by some patients taking levodopa. Tremor (choice A) is a symptom of Parkinson's but not directly caused by levodopa. Spasticity (choice B) is not typically associated with levodopa use. Akinesia (choice C) is a symptom of Parkinson's but not a direct effect of levodopa. Therefore, the correct answer is D due to levodopa's potential to cause the On-Off phenomenon in Parkinson's disease treatment.

Correct Answer: C

Rationale: The correct answer is C: Olanzapine. Olanzapine is an atypical antipsychotic medication, not an SSRI. SSRIs (Selective Serotonin Reuptake Inhibitors) are a class of antidepressants that specifically target serotonin reuptake. Fluvoxetine, Paroxetine, and Fluvoxamine are all SSRIs used to treat depression and anxiety disorders. Olanzapine, on the other hand, is primarily used to treat schizophrenia and bipolar disorder by targeting dopamine and serotonin receptors. Therefore, C is the correct answer as it does not belong to the class of selective SSRIs.

Correct Answer: C

Rationale: The correct answer is C: PAF. Platelet-activating factor (PAF) is the most potent agent increasing capillary permeability due to its ability to induce endothelial cell contraction and disruption of tight junctions. PAF also activates mast cells to release histamine, further enhancing vascular permeability. LTD4 can also increase capillary permeability but is less potent than PAF. PGD2 and TXA2 do not directly increase capillary permeability.

Correct Answer: D

Rationale: Bradykinin is a peptide that primarily causes smooth muscle contraction, dilatation of blood vessels, and pain by binding to its receptors. However, it does not directly cause liver cirrhosis. Liver cirrhosis is a chronic disease characterized by liver scarring due to various factors like alcohol abuse or hepatitis, not by the action of bradykinin. Therefore, the correct answer is D. Smooth muscle contraction, dilatation of blood vessels, and pain are all known effects of bradykinin based on its physiological functions, making them incorrect choices for this question.

Correct Answer: A

Rationale: The correct answer is A: Prostaglandins. Prostaglandins are known to induce uterine contractions, playing a crucial role in the process of labor. They stimulate smooth muscle contraction, including that of the uterus, leading to the initiation and progression of labor. Thromboxanes are involved in platelet aggregation, not uterine contractions. Leukotrienes are associated with inflammation and immune responses, not uterine contractions. NSAIDs inhibit prostaglandin synthesis, therefore, they would not cause uterine contractions.