Pharmacology Flashcards

Question

What is Paracetamol: An analgesic and Antipyretic compound?

Answer 1

Another name for paracetamol: Acetaminophen or Tylenol Paracetamol drug class: COX inhibitor Background: Cyclo-oxygenase is an enzyme that converts arachidonic acid into prostaglandins, which are part of the bodies inflammatory respone, contributing towards pain. COX exists in 2 forms, COX-1 and COX-2. They both possess long channels, COX-2's channel being slightly wider. COX-1 is involved in tissue homeostasis and is responsible for prostaglandin production in gastric cytoprotection and platelet aggregation. COX is also involved in the formation of thromboxanes - lipids that are involved in clot formation. Drug mechanism: Paracetemol is a weak inhibitor or prostaglandin synthesis, the exact mechanism is not clear. Paracetemol has no demonstratable anti-inflammatory activity. Indications (uses) : Mild-moderate pain and reduction of fever. Side effects: Side effects are rare. Rashes, blood disorders, hypotension. Contra-indications: Alcohol dependence Paracetamol is used when NSAIDs cannot be. An example is a patient with peptic ulcer. It has analgesic and antipyretic effects, but lacks ant platelet, anti-inflammatory, and gastric ulcerative effects. The mechanism of action is complex and not well understood. There are three possible mechanisms 1) It indirectly inhibits COX, which is ineffective in the presence of peroxides. This could explain why it does not work well within platelets. 2) It inhibits COX-3. This enzyme is not well understood. 3) Its antipyretic effects are due to effects on the hypothalamus, resulting in peripheral vasodilation and sweating.

Answer 2

A Pyridostigmine is a quaternary amine. As such it is poorly absorbed in the gut and doesn't cross the blood-brain barrier. However the mode of action of Pyridostigmine is the reversible inhibition of acetylcholinesterase in the synaptic cleft by competing with acetylcholine for attachment to acetylcholinesterase. This inhibition leads to a reduction in the hydrolysis of acetylcholine, prolonging its effects. Furthermore this reduction in hydrolysis increases efficiency of cholinergic transmission in the neuromuscular junction. Pyridostigamine has a slightly longer duration of action than neostigmine and is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.

Answer 3

Rifampicin is a broad spectrum antibiotic (targets both gram-positive and gram-negative organisms), which is easily absorbed and distributed within the body. Its mode of action is via the inhibition of DNA-dependent RNA polymerase, leading to a suppression of RNA synthesis and cell death. Importantly Rifampicin can target bacterial but not mammalian versions of the enzyme. Due to the emergence of resistant bacteria, the use of Rifampicin is restricted to Tuberculosis. Rifampin is metabolized in the liver and eliminated mainly in bile and, to a limited extent, in urine.

Answer 4

Summary: Fluconazole is a triazole antifungal used to treat various fungal infections including candidiasis. Candidiasis: fungal infection caused by yeast. Fluconazole Drug class : triazole antifungal Indication (reason) : - Treatment of the following fungal infections: Fluconazole can be administered in the treatment of the following fungal infections27: 1) Vaginal yeast infections caused by Candida 2) Systemic Candida infections 3) Both esophageal and oropharyngeal candidiasis 4) Cryptococcal meningitis 5) UTI (urinary tract infection) by Candida 6) Peritonitis (inflammation of the peritoneum) caused by Candida Mechanism of action: Fluconazole is a very selective inhibitor of fungal cytochrome P450 dependent enzyme lanosterol 14-α-demethylase. This enzyme normally works to convert lanosterol to ergosterol, which is necessary for fungal cell wall synthesis. These accumulated sterols negatively affect the structure and function of the fungal cell plasma membrane Contraindications ( reasons cant have): - If you've had an allergic reaction to fluconazole or any other medicines in the past. - heart disease, including heart rhythm problems (arrhythmia) -kidney or liver problems -a rare, inherited blood disorder called acute porphyria -had a blood test that showed you have abnormal levels of potassium, calcium or magnesium Side effects: headache diarrhea nausea or upset stomach dizziness stomach pain vomiting changes in the way food tastes severe rash in people with lowered immunity

Answer 5

Summary: Rivastigmine is a cholinesterase inhibitor used to treat mild to moderate dementia in Alzheimer's and Parkinson's. Rivastigmine drug class: cholinesterase inhibitor Indication (reason): For the treatment of mild to moderate dementia associated with Parkinson's disease or of the Alzheimer's type. Mechanism of action: Rivastigmine is a carbamate derivative that is structurally related to physostigmine, but not to donepezil and tacrine. The precise mechanism of rivastigmine has not been fully determined, but it is suggested that rivastigmine binds reversibly with and inactivates chlolinesterase (eg. acetylcholinesterase, butyrylcholinesterase), preventing the hydrolysis of acetycholine, and thus leading to an increased concentration of acetylcholine at cholinergic synapses. The anticholinesterase activity of rivastigmine is relatively specific for brain acetylcholinesterase and butyrylcholinesterase compared with those in peripheral tissues. Contraindications ( reason you cant have): Cardiac conduction conditions. Bradyarrhythmia or sick sinus syndrome. Chronic obstructive pulmonary disease or asthma. Bleeding ulcer history or risk. Seizure risk or history. Patient weight under 50 kg. Side effects: Rivastigmine may cause nausea, vomiting, diarrhea, stomach pain, loss of appetite, or weight loss.

Answer 6

Summary: Pyridostigmine is a cholinesterase inhibitor used for symptomatic treatment of myasthenia gravis and congenital myasthenic syndromes and to reverse neuromuscular blockade by nondepolarizing muscle relaxants. Pyridostigmine drug class: Anticholinesterases Cholinesterase inhibitor What is an acetylcholinesterase: acetylcholine is broken down by acetylchlinesterase in 2 steps - 1) acetylcholine is hydrolysed to free choline and acetylated enzyme. 2) The covalent acetyl-enzyme bond is split with the addition of water. Pyridostigmine drug mechanism: Has the same action as acetylcholine, except that the breakdown of the acetyl-enzyme bond is much slower, occupying up the acetylchlinesterase and preventing it from binding to acetylcholine. Indication (reason): Treatment of Myasthenia gravis. Contraindications: Asthma, bradycardia, arrythmias, recent MI, epilepsy, hypotension, intestinal or Side effects: nausea, vomitting,, increased salivation, abdominal cramps.

Answer 7

Myasthenia gravis is a rare long-term condition that causes muscle weakness. It most commonly affects the muscles that control the eyes and eyelids, facial expressions, chewing, swallowing and speaking. But it can affect most parts of the body Common symptoms: droopy eyelids double vision difficulty making facial expressions problems chewing and difficulty swallowing slurred speech weak arms, legs or neck shortness of breath and occasionally serious breathing difficulties The symptoms tend to get worse when you're tired. Many people find they're worse towards the end of the day, and better the next morning after getting some sleep.

Pharmacology Flashcards

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