NEET MDS Lessons
Pharmacology
Procoagulant Drugs:
Desmospressin Acetate
• Is a synthetic analogue of the pituitary antidiuretic hormone (ADH).
• Stimulates the activity of Coagulation Factor VIII
• Use for treatment of hemophilia A with factor VIII levels less than or equal to 5%, treatment of hemophilia B or in clients who have factor VIII antibodies. Treatment of severe classic von Willebrand's disease (type I) and when an abnormal molecular form of factor VIII antigen is present. Use for type IIB von Willebrand's disease.
Erythromycin
used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea.
Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.
Paracetamol
Paracetamol or acetaminophen is analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains.
paracetamol acts by reducing production of prostaglandins, which are involved in the pain and fever processes, by inhibiting the cyclooxygenase (COX) enzyme.
Metabolism Paracetamol is metabolized primarily in the liver. At usual doses, it is quickly detoxified by combining irreversibly with the sulfhydryl group of glutathione to produce a non-toxic conjugate that is eventually excreted by the kidneys.
Mefenamic acid
Analgesic, anti‐inflammatory properties less effective than aspirin
Short half‐lives, should not be used for longer than one week and never in pregnancy and in children.
Enhances oral anticoagulants
Used to treat pain, including menstrual pain. It decreases inflammation (swelling) and uterine contractions.
Class IV Calcium Channel Blockers
• Block the movement of calcium into conductile and contractile myocardial cells
• Treatment: treatment of supraventricular tachycardia
– Diltiazem
– Verapamil
Adverse Effects
• Adverse effects associated with vasodilation of blood vessels throughout the body.
• CNS – dizziness, weakness, fatigue, depression and headache,
• GI upset, nausea, and vomiting.
• Hypotension CHF, shock arrhythmias, and edema
Thrombolytic Agents:
Tissue Plasminogen Activator (t-PA, Activase)
t-PA is a serine protease. It is a poor plasminogen activator in the absence of fibrin. t-PA binds to fibrin and activates bound plasminogen several hundred-fold more rapidly than it activates plasminogen in the circulation.
Streptokinase (Streptase)
Streptokinase is a protein produced by β-hemolytic streptococci. It has no intrinsic enzymatic activity, but forms a stable noncovalent 1:1 complex with plasminogen. This produces a conformational change that exposes the active site on plasminogen that cleaves a peptide bond on free plasminogen molecules to form free plasmin.
Urokinase (Abbokinase)
Urokinase is isolated from cultured human cells.Like streptokinase, it lacks fibrin specificity and therefore readily induces a systemic lytic state. Like t-PA, Urokinase is very expensive.
Contraindications to Thrombolytic Therapy:
• Surgery within 10 days, including organ biopsy, puncture of noncompressible vessels, serious trauma, cardiopulmonary resuscitation.
• Serious gastrointestinal bleeding within 3 months.
• History of hypertension (diastolic pressure >110 mm Hg).
• Active bleeding or hemorrhagic disorder.
• Previous cerebrovascular accident or active intracranial bleeding.
Aminocaproic acid:
Aminocaproic acid prevents the binding or plasminogen and plasmin to fibrin. It is a potent inhibitor for fibrinolysis and can reverse states that are associated with excessive fibrinolysis.
Hypothalamic - Pituitary Drugs
Somatropin
Growth hormone (GH) mimetic
Mechanism
agonist at GH receptors
increases production of insulin growth factor-1 (IGF-1)
Clinical use
GH deficiency
increase adult height for children with conditions associated with short stature
Turner syndrome
wasting in HIV infection
short bowel syndrome
Toxicity
scoliosis
edema
gynecomastia
increased CYP450 activity
Octreotide
Somatostatin mimetic
Mechanism
agonist at somatostatin receptors
Clinical use
acromegaly
carcinoid
gastrinoma
glucagonoma
acute esophageal variceal bleed
Toxicity
GI upset
gallstones
bradycardia
Oxytocin
Mechanism
agonist at oxytocin receptor
Clinical use
stimulation of labor
uterine contractions
control of uterine hemorrhage after delivery
stimulate milk letdown
Toxicity
fetal distress
abruptio placentae
uterine rupture
Desmopressin
ADH (vasopressin) mimetic
Mechanism
agonist at vasopressin V2 receptors
Clinical use
central (pituitary) diabetes insipidus
hemophilia A (factor VIII deficiency)
increases availability of factor VIII
von Willebrand disease
increases release of von Willebrand factor from endothelial cells
Toxicity
GI upset
headache
hyponatremia
allergic reaction