Final answer:
Guanethidine lowers blood pressure by inhibiting the release of noradrenaline presynaptically, and its use can lead to orthostatic hypotension, not typically mental depression.
Step-by-step explanation:
The student's question pertains to the drug guanethidine and its pharmacological effects. Guanethidine produces an anti-hypertensive effect primarily by presynaptically inhibiting the release of noradrenaline. This action reduces sympathetic nervous system activity and, consequently, decreases blood pressure. Guanethidine is not highly lipid soluble, and due to its effects on the sympathetic nervous system, a side effect can be orthostatic hypotension, where blood pressure drops significantly upon standing up. Mental depression is not widely documented as a primary troublesome side effect of guanethidine. Instead, other side effects related to its mechanism of action, such as orthostatic hypotension, are more prominent.
which leads to a decrease in blood pressure. This drug is not highly lipid soluble and is more likely to affect the peripheral nervous system (PNS) rather than the central nervous system (CNS). Mental depression can be a troublesome side effect of guanethidine, while orthostatic hypotension is not a prominent side effect.