Questions tagged [pharmacology]

Pharmacology is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function.

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29 views

Why is therapeutic index a ratio instead of an interval?

The therapeutic index of a drug is defined as its toxic dose ($TD_{50}$) divided by its effective dose ($ED_{50}$). Why is it defined as a ratio rather than the difference $TD_{50} - ED_{50}$? For ...
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What is the difference between Molecular and Cellular tolerance?

Although I've read that there are three types of tolerance, molecular cellular and behavioural, I cannot seem to find any mechanism of cellular other than desensitization of receptors. If someone can ...
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Is PrEP used for anything other than HIV?

In the field of HIV prevention, PrEP is an abbreviation of pre-exposure prophylaxis. This is a very generic term. Are any diseases other than HIV prevented using a similar approach? Do they use the ...
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How does the dopamine spike from drugs compare quantitatively to pleasurable non-drug activities?

I did find this popular press article that quotes a researcher offering the following quantification: "in lab experiments done on animals, sex causes dopamine levels to jump from 100 to 200 units, and ...
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What is the relevance of the constant in the clearance equation?

I have seen the equation for drug half lives described variously as (0.7xVd)/Cl, (0.693xVd)/Cl, and (ln2xVd)/Cl. What is the origin of this numerical constant in the numerator? What does it signify?
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Is it true that ethanol can have some positive effects?

I recently was reading this inforgrafics about excessive alcohol use. It is written: No one should begin drinking or drink more frequently based on potential health benefits I am surprised. Is ...
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Can a drug induce specific mechanism of resistance in tumors?

For example, can a drug that targets a given protein induce overexpression of that protein or increase the copy number of the gene coding that protein? I strongly suspect that antineoplastic ...
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Gaba and Magnesium

I read read that magnesium divalent ion binds to gaba receptors and induces the same effects as if gaba has binded. Does anyone know what happens to the gaba that would have been synthesised and ...
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Could Racemic Epinephrine be used to Treat Anaphylaxis? [closed]

To be clear, this question is not a personal health question nor a question seeking health advice, it is only a theoretical question born of a curiosity for the pharmacology and biochemistry of ...
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50 views

Does ingestion of alcohol with methylphenidate make it act more like dexmethylphenidate?

Methylphenidate (MPH) is a dopamine and norepinephrine reuptake inhibitor. It is the racemic mixture of d-MPH and l-MPH. According to the binding profile info on Wikipedia, based on studies, it is at ...
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Why males are more prone to cardiovascular diseases such as heart attacks than females?

I often see more people of males undergoing treatment for heart disease. It is often said that female reproductive hormone (oestrogen) has some cardio-protective action by preventing constriction of ...
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Can a person be infected with Polio even after vaccination in childhood?

We know that a person develops antibodies by active immunisation after the administration of vaccines (either in dead form / live attenuated form). Is there any chance of developing the same disease ...
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Are there pre-synaptic alpha 2 receptors in the post-ganglionic synapses of the heart?

Are there pre-synaptic alpha 2 receptors in the post-ganglionic synapses of the heart? I haven't found any sources that clearly state whether they do or not. I'm also not sure if they exist in most ...
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Why do some texts say that noncompetitive antagonist dose no change in ED50 of agonist in Dose-respond curve?

Competitive antagonists increase the ED50 while the Emax remains the same. Non-competitive antagonists do not change the ED50 while decreases the Emax. I wonder how does this happen as Non-...
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Pharmacokinetics and cell-membrane permeability of Adenosine triphosphate disodium hydrate

【My Question】 (1) Please tell me the pharmacokinetics of this ATP (or Adenosine triphosphate disodium hydrate) when it is administered orally or intravenously. In particular, Does this material has ...
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421 views

Difference between "controlled release" vs "prolonged release"

My sister is using the epilepsy drug Tegretol which has both CR and retard (previous naming for prolonged release according to https://www.medicines.org.uk/emc/product/5932/smpc) versions in different ...
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Can you predict what the metabolites of pipradrol would be? Are they similar to those of methylphenidate? [closed]

As these drugs are structurally very similar, I am curious about how the body would handle them. Ritalinic acid is a major metabolite of methylphenidate, but that's about all I know. Thanks ...
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Protein inhibitory process

I usually find substances that activates proteins, like ApoA-I, but I don't find substances that inhibit it. So in an experimental design, could I consider the absence of a drug that directly acts ...
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What's the difference between veterinary and human snake antivenom?

Recently, out of curiosity, I looked online if snake antivenom for humans were actually sold for individuals. I found out they aren't. Not only that, but bills can get really high on countries that ...
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What would happen if VEGF was injected into a person?

Couldn't VEGF help with ligament recovery? I looked it up and found some studies in rats, but nothing on people. VEGF inhibitors tend to be used more often then VEGF. Why isn't VEGF being used in ...
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1answer
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Application of molecular dynamics simulation (or alternatives) for the full pathways of protein interactions?

If one would like to control the biological system (e.g. to treat disease or aging/senescence) then one should introduce the drugs in the system, that initiate complex protein interaction pathways ...
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What physiological pathways lie behind inhalants hallucinogenic effect?

I searched through the web and surprisingly I found pretty much nothing on the physiology of hallucinogenic effects of inhalants. Any idea how people get high with inhalants (household and industrial ...
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1answer
453 views

What exactly does 'reverse use-dependence' mean?

I understand 'use-dependence' related to a drug, for instance, more angiotensin2 effects in a hypertensive more prominent is the action of angiotensin2 receptor blockers. But I do not get the term, '...
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What structural features make a molecule a potent opioid receptor agonist?

For instance, take morphine. It is used as a baseline for measuring the potency of opioid agonists. Its structure looks like this: But then, take heroin, around three times as potent, its structure ...
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Is it impossible to increase skeletal bone mass, as opposed to just bone density? [closed]

I've heard exercise and resistance/strength training increases the density, but doesn't increase mass. So basically, experimentally or theoretically possible at least, can modern science do this/is it ...
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Could certain drugs enable one to consistently eat above TDEE or BMR without fat gains?

I heard anabolic steroids and stuff like DNP and ephedrine and etc. can somewhat enable one to eat more and get away with it without much or any fat gain, despite eating more than the body would ...
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How are drugs distributed in regards to bone marrow?

I know that as volumes of distribution increase they correspond to the blood, then the vascular rich group (heart, kidneys, liver, brain if BBB permeable), then muscle then adipose. But things like ...
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Why does our body absorb toxic substances or toxic concentrations of a substance if it is capable of regulating gastrointestinal absorption?

Our gastrointestinal system is filled with regulatory molecules that place brakes in the absorption process. For instance, the food that we consume daily is filled with harmful substances that our ...
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1answer
2k views

What is a Archival Tumor Tissue ? For What Purpose is it collected?

Over the course of Conducting trials various tissue and tumor samples are collected from the patients. One such sample is the Archival Tumor Tissue. Could someone kindly clarify what is the meaning ...
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Do antimuscarinic drugs increase cAMP or cGMP

Activation of muscarinic receptors M2 and M4 inhibits adenylate cyclase which reduces cAMP levels. It would be expected that antimuscarinics such as ipratropium would increase cAMP levels. However, ...
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How does the body detect irreversible binding to receptors?

I have read an article on Wikipedia about irreversible agonists and antagonists. These permanently bind to a target receptor on a cell. However, the receptor protein is then internalized and recycled ...
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Can (or have) antiviral drugs created drug-resistant viruses?

Evolution/emergence of antibiotic-resistance in bacteria is a known effect of extensive use of pharmaceutical antibiotics. Pharmaceutical antivirals have come into extensive use in recent decades – e....
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Influenza infections and drug design

Why is the neuraminidase used as a target for drugs against influenza virus instead of haemagglutinin? Is there some basic reason that this will make a more effective drug?
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Is reverse senescence/"anti-aging" actually scientifically possible among humans yet?

I have been very interested in this since I myself am interested in reversing my skin's aging/genes/damage/etc. I also am interested in volunteering any future genetic altering of skin quality. ...
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What happens to drug metabolism when CYP450 enzymes are presented with two substrates

What happens when two substances, both substrates for Cytochrome P450 metabolism, are both present in the bloodstream? For example, with sertraline and cannabidiol (CBD), if someone took a sertraline ...
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Does reversion of resistant strains to wild-type only occur when no more drug pressure is exerted

We always read that wild-type reversion of a resistant strain occurs when no more drug pressure is exerted. Could resistance reversion also occur under drug pressure, but from a drug other than the ...
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How does alcohol interact with sympathomimetics to affect the cardiovascular system?

There is a fair amount of information on the cardiovascular effects of alcohol, and of sympathomimetics. How do they work? And how do their mechanisms interact? We know that similar pathologies ...
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Why are $\beta_2$ receptors present on bronchial smooth muscles , considering that they have only parasympathetic innervation?

It is well known that the bronchial muscles have only parasympathetic innervation. But they still express $\beta_2$ receptors. How does this system still cause bronchial relaxation? What is the exact ...
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1answer
199 views

What characteristic(s) of inverse agonists allow for inhibitory effects?

I know that inverse agonists have similar structure to its complement agonist; and, as a result, they have the ability to bind to the same receptor, causing an inhibition of the pathway considered. ...
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1answer
2k views

Why are semi log graphs used in drug Dose response curves?

Why are Dose response curves, as well as most biological graphs shown in semi log graphs and not normal graphs? What is the advantage of semi log graphs over regular graphs? I still haven't gotten an ...
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664 views

Why is atropine a CNS stimulant, although it blocks the muscarinic receptors in the brain?

I know that atropine is a muscarinic antagonist, so why does atropine have excitatory actions on the brain while it is blocking muscarinic receptors?
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Hematuria due to Nitric Oxide

Drug interactions between properly dosed NO and other medications are not expected, but side effects may include noisy breathing, hematuria, or possibly atelectasis. (pg.no:577; Goodman and Gilman ...
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Umbrella term for agonist, antagonist, inverse antagonist, etc.

For most receptors there exist different ligands that induce different responses. Depending on the response these different ligands can be classified into different groups such as agonists, ...
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1answer
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Which kind of drugs get absorbed through epidermis?

Some drugs such as nicotine can be administered through skin. I thought the layers of skin are designed to prevent in-flow of any chemical/germs. Not all drugs get absorbed in this fashion. So do ...
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Humans have Cannabinoid receptors. Does that mean we're meant to consume cannabis?

I know the answer is no. But what then explains the name of these receptors being specific to Cannabinoid found in cannabis? Aren't Cannabinoid receptors exclusive to Cannabinoid? Why are they named ...
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1answer
549 views

İrreversible dopamine antagonist vs. Dopamine agonist

Can a dopamine agonist reverse the effects of an irreversible dopamine antagonist?
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1answer
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How long does it take for a blocked dopamine receptor to be broken down by the body?

Do the blocked dopamine receptors get broken down by the body and if so how often ? In other words how long does it take for the dopamine receptors blocked by irreversible dopamine antagonists to ...
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463 views

Why do new atypical antipsychotics like Zyprexa cause TD at lower rates?

When the d2 receptors are blocked for long periods of time they tend to up regulate. This is what causes tardive dyskinesia. Why do the newer atypical anti psychotics cause such at a lower rate? ...
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Mechanism by which hypokalemia reduces insulin secretion

Is there any known mechanism by which hypokalemia reduces insulin secretion? This video explains a mechanism, but its inherently wrong because ATP dependent K+ channels will allow movement of K+ from ...
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Is an X ml dose of a drug at 50% bioavailability roughly equivalent to a 2X ml dose at 25% bioavailability?

For the sake of simplicity, assume: The two doses are the same drug metabolized in the exact same way, and the only difference is the amount that reaches the bloodstream (and thereafter the brain). ...

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