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
17
Q
What is the action and some features of gentamicin?
A
- Antibiotic of the aminoglycoside class.
- Acts at 30s subunit to inhibit translation initiation, therefore also inhibiting protein synthesis.
- Like all aminoglycosides, is ototoxic.
- They are BACTERICIDAL
18
Q
What is the action and some features of heparin?
A
- Anticoagulant.
- A long, unbranched polysaccharide chain composed of repeating disaccharide units.
- Allosterically activates antithrombin-III; stabilises ATIII-thrombin interaction by 2000-4000x, promoting thrombin breakdown by this serpin.
- ATIII (anti-thrombin III) is an endogenous inhibitor of coagulation factors, especially Factor Xa and Thrombin (IIa)
- Heparin stabilises these interactions, slowing the clotting cascade
- Therefore, it is useful for prevention and treatment of thrombosis
- Active in minutes so given to reduce risk of clots in acute MI.
- Given as IV bolus then subcutaneous
- Can cause severe bleeding and Heparin-induced thrombocytopenia (low levels of platelets)
19
Q
What is the action and some features of imatinib?
A
- Aka Glivec
- Targetted chemotherapy drug - small molecule inhibitors of cell cycle enzymes.
- Small-molecule inhibitor of the tyrosine kinase product of the BCR-ABL fusion gene on the Philadelphia chromosome.
- It is also effective against other tyrosine kinases, so it is effective against multiple types of cancer
- Used to treat Philadelphia +ve cancers; almost all chronic myelogenous leukaemias, some chronic lymphoblastic leukaemias.
20
Q
What is the action and some features of isonizid?
A
- Antibiotic, specifically against mycobacteria.
- Works by inhibiting synthesis of long-chain mycolic acids.
- Bactericidal to growing organisms, otherwise bacteriostatic
21
Q
What is the action and some features of maraviroc?
A
- Used to treat HIV.
- Prevents entry by binding and blocking CCR5.
- Fairly significant risk of hepatotoxicity.
22
Q
What is the action and some features of methotrexate?
A
- Antimetabolite used as a cytotoxic chemotherapy agent.
- Close analogue of folic acid - competitive inhibitor of DHFR.
- This inhibits synthesis of purines and dTMP
- Thus, this inhibits RNA synthesis and DNA replication
- Also used as a first-line DMARD in rheumatoid arthritis.
23
Q
What is the action and some features of NSAIDs?
A
- Class of drugs which inhibit COX. Inhibit synthesis of lipid mediators of inflammation - prostaglandins, leukotrienes, PAF. Reduce inflammation and oedema.
- Prostaglandins sensitise C-fibre pain neurons, so NSAIDs reduce inflammatory pain.
24
Q
What is the action and some features of oseltamivir?
A
- Aka Tamiflu
- Antiviral used to treat influenza. Also can be preventative for those at high risk.
- Competitive inhibitor of neuraminidase. Prevents cleavage of sialic acid residues so release of new virions.
25
Q
What is the action and some features of paracetamol?
A
- Analgesic but not considered an NSAID as it doesn’t reduce inflammation. Also has antipyretic properties.
- Appears to inhibit COX (according to spec, “a specific COX”) - action seems to come from inhibition of COX2 in the brain.
- Its metabolite AM404 is a weak cannabinoid receptor agonist, which may also contribute to analgesia.
26
Q
What is the action and some features of penicillin?
A
- 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
27
Q
What is the action and some features of raltegravir?
A
- Inhibits integrase. Used to treat HIV. May also be used as part of post-exposure prophylaxis.
- Prevents integration of viral DNA into the human genome so transcription of viral mRNA.
28
Q
What is the action and some features of rifampicin?
A
- Of the rifamycin class of antibiotics.
- Inhibits bacterial RNA polymerase [DNA-dependent] so inhibits transcription.
- Used particularly for TB.
- They are BACTERICIDAL or BACTERIOSTATIC
29
Q
What is the action and some features of saquinavir?
A
- HIV protease inhibitor, used to treat or prevent HIV.
- Protease required for cleavage of HIV polyproteins to release functional HIV proteins.
30
Q
What is the action and some features of simvastatin?
A
- Statin, so is a HMG-CoA reductase inhibitor.
- Inhibits cholesterol biosynthesis, lowers plasma LDL.
- They also increases hepatic LDL receptor expression
- This leads to decreased plasma LDL and plasma triglycerides, as well as slightly increased plasma HDL
- Reduces risk/slows progression of atherosclerosis and thus coronary heart disease.
31
Q
What is the action and some features of streptokinase?
A
- Thrombolytic agent.
- The enzyme of beta-haemolytic Streptococci - dissolves blood clots by converting plasminogen to plasmin.
- Used in treatment of acute MI with aspirin.
- However most individuals have anti-streptokinase antibodies. Not recommended to be used twice in a person’s lifetime.
- Administration: IV infusion or via catheter at site of arterial blockage
- Side-effects: increased risk of bleeding, nausea.
- Contraindictions:
- Recent Strep infection
- Stroke
- Pregnancy
32
Q
What is the action and some features of streptomycin?
A
- Antibiotic of the aminoglycoside class.
- Acts at 30s subunit to inhibit translation initiation and therefore prevents protein synthesis.
- Like all aminoglycosides, is ototoxic.
- BACTERICIDAL
33
Q
What is the action and some features of tamoxifen?
A
- Hormonal therapy for breast cancer
- Oestrogen receptor modulator.
- In breast tissue, acts as an ER antagonist. Used to treat ER-positive breast cancer.
- Thus, it stops the growth of breast cells
- It is metabolised to hydroxytamoxifen
- It may also have other unknown mechanisms of action
34
Q
What is the action and some features of tetracycline?
A
- Antibiotic of the tetracycline class.
- Acts at ribosomal 30s subunit to inhibit tRNA binding.
- Inhibits protein synthesis
- BACTERICIDAL
- Can be exported by membrane pumps
- [[spec incorrectly classifies this as an aminoglycoside, it acts at the same ribosomal subunit but is its own class]]
35
Q
What is the action and some features of trastuzumab?
A
- Aka Herceptin
- Anti-HER2/Neu monoclonal antibody.
- Blocks the growth factor receptor HER2, inhibits neoplasia where growth is driven by its overexpression.
- This down-regulates the growth factor signals that are mediated by the HER2 receptors and it also induces antibody-dependent cellular cytotoxicity (ADCC)
- HER2+ breast cancer and HER2+ stomach cancer
36
Q
What is the action and some features of trimethoprim?
A
- Antibiotic of the 2,4-diaminopyridine class.
- Dihydrofolate reductase (DHFR) inhibitor - this converts dihydrofolate to tetrahydrofolate so inhibits nucleotide synthesis.
- They are BACTERIOSTATIC (but bactericidal when combined with sulfonamides)
37
Q
What is the action and some features of vincristine?
A
- Vinca alkaloid
- Used as a cytotoxic chemotherapy agent.
- Binds to tubulin and prevents polymerisation into microtubules, so prevents movement and separation of chromatids in metaphase and leads to apoptosis.
- Side-effects: hair loss, change in sensation/neuropathic pain, difficulty walking, headaches.
- Dangers of vinca alkaloids such as vincristine:
- They are severely neurotoxic, since they inhibit microtubules, which are essential in neurons for neurotransmitter transport.
- Therefore they cannot be administered into the CSF, but must be administered via IV
38
Q
What is the action and some features of warfarin?
A
- Vitamin K epoxide reductase inhibitor.
- This re-reduces oxidised vitamin K to reduced vitamin K. Requires oxidation of NADH.
- In coagulation factors, the glutamic acid residues must be gamma carboxylated into order to bind calcium, which is necessary for formation of complexes with platelet surfaces.
- This gamma carboxylation is dependent on vitamin K.
- Reduced Vitamin K is a cofactor for factors 2, 7, 9 and 10 (2 is thrombin) - anticoagulant.
- Used for prophylaxis/treatment of:
- DVT, pulmonary embolism
- Thrombosis after heart valve replacement or MI/AF
- Problems:
- Narrow therapeutic window
- Risk of haemorrhage
- Many drug-drug interactions as it binds to albumin in plasma
- Contraindictions - pregnancy, alcoholism
39
Q
What is the action and some features of zanamivir?
A
- Aka Relenza
- Antiviral used to treat influenza. Also can be preventative for those at high risk.
- Competitive inhibitor of neuraminidase. Prevents cleavage of sialic acid residues so release of new virions.
40
Q
What is the action and some features of zidovudine?
A
- Aka Azidothymidine/AZT
- Of the chain terminator class of RT inibitors. Also known as nucleoside RT inhibitors.
- Thymidine analogue that prevents DNA chain extension.
- Used for treatment and prevention of HIV, prevents viral replication.
