Inhibitors of the ADP receptor pathway include clopidogrel and ticlopidine. It is believed that covalent alteration and inactivation of the platelet P2Y ADP receptor caused the irreversible suppression of the ADP-dependent mechanism of platelet activation. This receptor and the suppression of adenylyl cyclase are linked. Both medications are prodrugs that the liver transforms into active metabolites. But in order for clopidogrel to become active, hepatic P450 enzymes must oxidize it.
The choice of antidepressant medicine for older persons should be made with a number of factors in mind, most importantly side effects and the possibility of drug-drug interactions. As was mentioned in response to question 50, the tricyclic antidepressants (TCAs) have a number of adverse effects, such as aberrant cardiac conduction and drug-drug interactions, which render them unsuitable for the treatment of depression in older persons. In this patient, a selective serotonin reuptake inhibitor is preferable to a TCA. Escitalopram does not have a high risk of drug-drug interactions like fluvoxamine does. Due to its strong protein binding capacity, fluvoxamine may interact with drugs that prevent blood clotting, such warfarin. Escitalopram is thus the drug that is most suitable for this patient out of those listed. Psychotropic drugs for older persons should be begun at a low dose and gradually increased to the lowest therapeutic dose.
The primary pathway is glucuronidation, which the liver's UDP-glucuronyl transferase catalyzes. The second most frequent method is sulfation, and NAC treatment targets this mechanism. The liver necrosis brought on by acetaminophen overdose is induced by the synthesis of N-acetyl-p-benzoquinone imine, which is produced as a result of cytochrome P-450 oxidation. About 5% of acetaminophen metabolism is represented by direct renal excretion. In most cases, acetaminophen does not undergo plasma metabolism.
Dapsone competes with para-aminobenzoate for the dihydropteroate synthetase active site, which prevents bacteria from producing dihydrofolic acid. Against M, dapsone is both bacteriostatic and somewhat bactericidal. leprae. These effects are not brought about by any of the above mechanisms. Clofazimine, a drug with anti-leprosy and anti-inflammatory properties, is only marginally bactericidal against M. leprae, not by directly adhering to DNA polymerase, but by attaching to the guanine nucleotides of bacterial DNA. By limiting RNA synthesis and preventing DNA-dependent RNA polymerase, rifampin kills bacteria.
Acute sinusitis symptoms are seen in this patient. Viruses are the most frequent cause of these diseases. A shorter incubation period (less than 10 days) and the absence of purulent discharge (hers is watery) are signs that an infection is viral as opposed to bacterial. She doesn't display any signs of a problem arising and even mentions that her symptoms are getting better. If her symptoms were caused by a bacterium, Streptococcus pneumoniae, Haemophilus influenza, and Moraxella catarrhalis are the most frequent causes of acute sinusitis. Patients with chronic sinusitis (sinusitis lasting more than 12 weeks) are more likely to have anaerobic bacteria such Bacteroides fragilis and Staphylococcus aureus in their systems. Before giving these people antibiotics randomly, it's crucial to understand this.
It is not required that all medications administered orally are fully absorbed. Many of them have only partially been absorbed. With oral intake of medications, the degree of absorption ranges from 5 to less than 100%. Atenolol is an example of a medicine that is excessively hydrophilic and cannot pass the lipid barrier, which results in inadequate absorption. Similar to this, medications like acyclovir that are very lipophilic are not soluble enough to pass through the water layer next to the cell. P-glycoprotein, an efflux transporter, is found in enterocytes and prevents drugs from being absorbed. In addition, it goes by the names export transporter and reverse transporter. Its substrate is a wide variety of medicines. In reality, grape juice inhibits P-glycoprotein in the intestine, reducing P-glycoprotein's ability to remove drugs from cells. Therefore, drinking grape juice may considerably boost the drug's absorption.
The American Thyroid Association (ATA) recommends propylthiouracil (PTU) for the treatment of hyperthyroidism in pregnant women who are in their first trimester. Methimazole is contraindicated in the first trimester because it has been linked to congenital malformations, including aplasia cutis in rare instances. The use of PTU has a risk of liver damage, hence the ATA advises switching to methimazole once in the second trimester.
