Pharmacology S8 Flashcards
Fibrinolytic Drugs mechanism of action
Amplify the conversion of an inactive enzyme precursor plasminogen to active enzyme plasmin.
1 st generation thrombolytics
Streptokinase
Urokinase
Clinical uses of thrombolytics
Myocardial infarction
- Pulmonary embolus ( massive )
- Acute ischaemic stroke
Plasminogen
Plasmin
A single chain glycoprotein. 790 AA.
Converted to plasmin by cleavage of ARG560-Valine561 peptide band
Serine protease with trypsin like activity.
Attacks lysyl & arginyl bands of fibrin.
Streptokinase
From -haemolytic streptococci
available as streptokinase ™
• Antigenic (bacterial origin) so only used once per patient *
Non enzymatic protein of beta-haemolytic streptococci.
Activates fibrinolytic system by forming 1:1 stoichiometric complex with plasminogen converting to active enzyme plasmin
Urokinase
Trypsin –like serine protease of 2 polypeptide chains activates plasminogen directly converting it to plasmin.
2 nd generation Thrombolytics
Anistrelplase
APSAC acetylation of plasminogen. T1/2 = 90mins. Permit bolus dosing. Less bradykinin produced than with Streptokinase ( hypotension )
3 rd generation thrombolytics
Reteplase – recombinant plasminogen activator.
Half life 18mins 2 iv bolus injections 30mins apart Tenecteplase – multipoint mutation of parent
tPA
3 rd generation thrombolytics
Give E
Reteplase
Tenecteplase
phase-specific ca drugs
S-specific
M-specific
cytaribine
Vincristine
Cell cycle specific drugs
Give examples
Antimetabolites Bleomycin peptide Antibiotics Vinca alkaloids Etoposide
Cell cycle non specific drugs
Alkylation agents
Antibiotics
Cisplatin
Nitrosoureas
Anthracyclines mechanism of action
Topoisomerase inhibition prevents the enzyme from religating cleaved DNA
Anthracyclines
Give examples
doxorubicin
Alkylating agents
mechanisms of action
formation of DNA cross links – interferes with cellular replication
Alkylating agents
Give examples of
cyclophosphamide
Antimetabolites
mechanisms of action
disrupt the synthesis of essential compounds required for cell synthesis
- methotrexate inhibits the enzyme required to convert folate to its active form
- cytarabine inhibits DNA synthesis
Antimetabolites
Give examples
methotrexate inhibits the enzyme required to convert folate to its active form
• - cytarabine inhibits DNA synthesis
Vinca Alkaloids
mechanisms of action
bind to tubulin – prevent formation of the mitotic spindle
Vinca Alkaloids give examples
vincristine
Reversal of heparin therapy with
Protamine sulphate
Antidote of thrombolytics
tranexamic acid
Major bleeds may need:
blood, fresh plasma plasma, cryoprecipitate, recombinant clotting factors
