What is pharmacodynamic drug tolerance?
Pharmacodynamic tolerance occurs when the intrinsic responsivity of the receptor system diminishes over time. Acute tolerance is mediated predominantly by pharmacodynamic mechanisms, manifested as a decreased response following a single administration of the agent or during repeat-dosing but over a short time frame.
How does pharmacodynamic tolerance develop?
Pharmacodynamic tolerance begins when the cellular response to a substance is reduced with repeated use. A common cause of pharmacodynamic tolerance is high concentrations of a substance constantly binding with the receptor, desensitizing it through constant interaction.
What is acute tolerance to nicotine?
Acute Tolerance to Nicotine is Dose-Dependent and Region-Specific. Repeated nicotine administration induced profound tachyphylaxis development. Figures 4b and c and Table 2 depict the time courses and biphasic nature of the peak effects as well as the tolerance profiles associated with the repeated nicotine injections.
How does pharmacodynamic tolerance develop quizlet?
Concentration of drug in blood vs response curve shifts to the right for pharmacodynamic tolerance. The tolerance mechanism is at the site of action, opposing the effect of the drug at its locus or receptor. Need more drug in blood to get the same response.
When does nicotine tolerance develop?
Tolerance to nicotine-induced decreases in locomotor activity and body temperature were observed. Tolerance to the effects of nicotine on both of these measures developed rapidly, with maximal changes occurring within 2-4 days after initiation of treatment.
What is the mechanism of action of nicotine?
Nicotine mainly shows its action through specific nicotinic acetylcholine receptors located in brain. It stimulates presynaptic acetylcholine receptors thereby enhancing Ach release and metabolism. Dopaminergic system is also stimulated by it, thus increasing the concentration of dopamine in nuclear accumbens.
When tolerance to one drug results in tolerance to another drug What is it referred to as?
Cross-tolerance is a phenomenon that occurs when tolerance to the effects of a certain drug produces tolerance to another drug. It often happens between two drugs with similar functions or effects—for example, acting on the same cell receptor or affecting the transmission of certain neurotransmitters.
What does drug tolerance refer to?
Listen to pronunciation. (… TAH-leh-runts) A condition that occurs when the body gets used to a medicine so that either more medicine is needed or different medicine is needed.
Can you build a tolerance to nicotine?
Your body is able to build up a high tolerance to nicotine, so you’ll need to smoke more cigarettes to get that same buzz. This up and down cycle happens over and over. That’s what leads to addiction.
Which best describes the pharmacokinetic profile of nicotine?
Nicotine pharmacokinetics were best described with a one‐compartment model with absorption based on a Weibull distribution and first‐order elimination and a single compartment for the major metabolite, cotinine.
What is the physiological basis of the short term effects of nicotine?
Immediately after exposure to nicotine, there is a “kick” caused in part by the drug’s stimulation of the adrenal glands and resulting discharge of epinephrine (adrenaline). This rush of adrenaline stimulates the body and causes an increase in blood pressure, respiration, and heart rate.
What are the three types of tolerance to a drug?
Tolerance typically is divided into three functional categories (acute, rapid, and chronic), but determining precisely which molecular underpinning underlies which class of tolerance (or if they are exclusive) can be difficult.
What is mechanism of tolerance?
Generally, tolerance leads to increasing doses of a drug being required to produce the same effect. Other possible mechanisms are a decrease in binding affinity between a drug and receptor and a decrease in the number of receptors. The mechanisms responsible for drug tolerance are not always known.
What is the mechanism of tolerance?
Tolerance is defined as the diminished response to alcohol or other drugs over the course of repeated or prolonged exposure. This mechanism allows physiological processes to achieve stability in a constantly changing environment.
What is pharmacodynamics testing?
Pharmacodynamic studies in general represent a very heterogenic group of methods, highly dependent on the drug’s specific pharmacological effect. These tests are also related to the amount of the free, unbound drug, which will be able to produce the therapeutic effect and subsequently certain behavioral symptoms.