Drugs list Flashcards
1
Q
What is the action and some features of aciclovir?
A
- Guanosine analogue. Converted by viral thymidine kinase (but not human thymidine kinase) to aciclovir triphosphate, which inhibits DNA polymerase in infected cells.
- During DNA synthesis mediated by the infection, the acyclovir triphosphate is incorporated into the chain
- This terminates synthesis because there is no 3’ carbon on the acyclovir, so no more nucleotides can be added to the chain
- This prevents the virus from completing the cycle
- This is selectively toxic to the virus because the human cell can differentiate between the guanosine and the acyclovir
- Used against HSV-1 and HHV-3 (varicella zoster) herpesviruses.
2
Q
What is the action and some features of adrenaline in reference to immunopathology?
A
- Strong β-adrenoreceptor agonist
- Immediate treatment for type 1 hypersensitivity reactions
- Asthma, acutely - acts at β2, bronchodilatory.
- Anaphylaxis - strong vasoconstrictor, counters the systemic vasodilation to prevent vasodilatory shock
3
Q
What is the action and some features of amoxicillin?
A
- Type of penicillin
- β-lactam antibiotic.
- Binds to and inhibits penicillin-binding proteins (PBP) - transpeptidases involved in peptidoglycan synthesis.
- They are structural analogues of the peptide cross-bridges in peptidoglycan
- Therefore, they can preferentially bind to the transpeptidase enzymes (one of the penicillin binding proteins PBPs)
- This stops transpeptidation, so the peptidoglycan cannot form
- BACTERICIDAL
- More effective against Gram +ve bacteria as target more accessible
- Resistance seen in some bacteria through beta-lactamases
4
Q
What is the action and some features of aspirin?
A
- Cyclooxygenase I and II non-competitive, irreversible inhibitor, acetylates them.
- Reduces synthesis of prostaglandins, reduces inflammation. Prostaglandins sensitise C-fibre pain neurons so aspirin reduces inflammatory pain. NSAID.
- As a NSAID, used in chronic inflammatory diseases such as rheumatoid arthritis.
- Causes ototoxicity at high doses.
- Low doses: mild indigestion, risk of bleeding
- Reduces synthesis of thromboxane A2, a major platelet activator and stimulator of aggregation. Of the antiplatelet agent class of anticoagulants as platelets have no nucleus so cannot synthesise more COX once inhibited.
- Given long-term for prophylactic prevention of clotting for those at risk, or acutely after MI to reduce risk of clots.
- Problems of long-term aspirin:
- Liver/kidney disease
- Uncontrolled bleeding
- GI problems
- Aspirin allergies
- Doesn’t mix well with alcohol
5
Q
What is the action and some features of benzylpenicillin?
A
- Type of penicillin
- β-lactam antibiotic.
- Binds to and inhibits penicillin-binding proteins (PBP) - transpeptidases involved in peptidoglycan synthesis.
- They are structural analogues of the peptide cross-bridges in peptidoglycan
- Therefore, they can preferentially bind to the transpeptidase enzymes (one of the penicillin binding proteins PBPs)
- This stops transpeptidation, so the peptidoglycan cannot form
- BACTERICIDAL
- More effective against Gram +ve bacteria as target more accessible
- Resistance seen in some bacteria through beta-lactamases
6
Q
What is the action and some features of chloroquine?
A
- Antimalarial, both prophylactic and therapeutic.
- In schizogony in erythrocytes, Plasmodium must degrade haemoglobin for its own use, in an acid vesicle.
- Chloroquine concentrates in this vesicle and prevents crystallisation of toxic haem to nontoxic haemozoin; also binds to haem to form highly toxic FP-chloroquine.
- Causes cell lysis and parasite autodigestion.
7
Q
What is the action and some features of chloramphenicol?
A
It is an antibiotic that inhibits bacterial protein synthesis by binding to bacterial ribosomes.
It is a potent, broad-spectrum antibiotic used for eye, ear, and life-threatening infections.
*It binds to the 23 S rRNA on the 50S subunit.
8
Q
What is the action and some features of chlorpheniramine?
A
- First-generation antihistamine, H1 antagonist. Aka chlorphenamine.
- Inhibits type I hypersensitivity reactions. Usually used for mild allergic conditions such as allergic rhinitis (hayfever).
- Side-effects: sleepiness, weakness, dry mouth.
9
Q
What is the action and some features of ciprofloxacin?
A
- Antibiotic of the fluoroquinolone class.
- Binds to DNA gyrase, causing introduction of double-strand breaks in DNA.
- They are BACTERICIDAL or BACTERIOSTATIC
10
Q
What is the action and some features of cisplatin?
A
- Alkylating agent used in cytotoxic chemotherapy.
- Platinum bound to two NH3 and two Cl. Cl displaced by water, cross-links DNA bases.
- Remarkably effective in testicular cancer, even metastatic.
- Increased cure rate from 10% to 80%
- Displacement of the chlorine allows cross-linking of the DNA strands
- This leads to cytotoxicity
11
Q
What is the action and some features of cromoglicate?
A
- Described as a mast cell stabiliser, inhibits degranulation.
- Used to prevent type I hypersensitivity reactions, as chronic prophylaxis in asthma.
- Long-term treatment
- Largely replaced by leukotriene receptor antagonists due to their convenience - cromoglicate must be taken 4 times a day.
12
Q
What is the action and some features of cyclophosphamide?
A
- Alkylating agent used in cytotoxic chemotherapy.
- Chloride atoms displaced to crosslink nitrogens of guanine bases.
- In vivo it is oxidised to phosphoramide mustard
- The chlorines can take part in displacement reaction, which cross-link the DNA strands and can induce damage
- It is effective in treating cancer and other conditions (e.g. rheumatoid arthritis)
- Selectivity is determined by:
- The aldophosphamide intermediate is detoxified by aldehyde dehydrogenase (ALDH)
- This confers some selectivity for cells with low ALDH
13
Q
What is the action and some features of dexamethasone?
A
- Steroid - synthetic glucocorticoid.
- Acts at nuclear glucocorticoid receptors, reduces phospholipase A2 synthesis. Reduces synthesis of lipid mediators of inflammation - prostaglandins, leukotrienes, platelet activating factor. Reduces inflammation and oedema.
- Prostaglandins sensitise C-fibre pain neurons, so reduces inflammatory pain. Analgesic.
- Side-effects:
- Immune depression, susceptibility to infection
- Hypertension - action at mineralocorticoid receptor, sodium/fluid retention
- Bone resorption, diabetes, peptic ulcers, impaired skin healing
14
Q
What is the action and some features of doxorubicin?
A
- Aka Adriamycin
- Used as cytotoxic chemotherapy.
- Very planar and intercalates between base pairs.
- Stabilises DNA topoisomerase II at reaction intermediate with double-strand breaks.
- Prevents detangling of sister chromatids and induces double-strand breaks.
- Topoisomerase is expressed most during G2 of the cell cycle.
- This means that the cells in this phase are most susceptible to doxorubicin
15
Q
What is the action and some features of erythromycin?
A
- Antibiotic of the macrolide class.
- Acts at ribosomal 50s subunit to inhibit translocation of tRNA, preventing protein synthesis
- They are BACTERICIDAL/BACTERIOSTATIC
16
Q
What is the action and some features of flucloxacillin?
A
- Type of penicillin
- β-lactam antibiotic.
- Binds to and inhibits penicillin-binding proteins (PBP) - transpeptidases involved in peptidoglycan synthesis.
- They are structural analogues of the peptide cross-bridges in peptidoglycan
- Therefore, they can preferentially bind to the transpeptidase enzymes (one of the penicillin binding proteins PBPs)
- This stops transpeptidation, so the peptidoglycan cannot form
- BACTERICIDAL
- More effective against Gram +ve bacteria as target more accessible
- Resistance seen in some bacteria through beta-lactamases
