pharmacology - hematologic drugs

Hematologic Drugs

Hematologic drugs

There are numerous agents utilized to maintain, preserve and restore circulation. The three important dysfunction of blood are thrombosis, bleeding and anemia are commonly treated with various agents. The common ones that nurses must REVIEW are the:

• Anticoagulants• Antilipemics• Antiplatelets (antithombotics)• Thrombolytics• Anti-anemics or Hematinics• Drugs to treat bleeding

The Anti-Coagulants

The anticoagulants interfere with the coagulation process by interfering with the clotting cascade and thrombin formation. These agents are used to inhibit clot formation, but they do NOT dissolve existing clots.

• The Anticoagulants commonly used are:• Heparin• Warfarin (Coumadin)• Dicumarol• Anisindione (Miradon)

Heparins

These are anticoagulants given orally or parenterally- SQ and IV.

Heparin is naturally found in the human liver that normally prevents clot formation.

Heparin is strongly acidic because of the presence of sulfate and carboxylic acid groups in the heparin chain.

Heparin

The mechanism of action of HeparinHeparin (Liquamen Sodium) acts

prophylactically to prevent the formation of blood clots in the vasculature.

It combines with ANTITHROMBIN III, a substance in our blood sometimes called heparin factor that inactivates THROMBIN.

By inhibiting the action of thrombin, conversion of fibrinogen to fibrin does not occur and the formation of a fibrin clot is prevented.

Heparins

Clinical Indications of Heparins• deep vein thrombosis • pulmonary embolism• coronary thrombosis, • patients with artificial heart valves and stroke patients

Heparins

Contraindications of heparin• Anticoagulants are not given to patients with bleeding

disorders, peptic ulcers and patients who underwent recent eye/brain/spinal surgery.

• It is NOT given to patients with severe liver and renal disease, hemophilia, and CVA.

• Heparin is a large protein molecule that cannot pass through the placenta easily and can be given to pregnant women.

HeparinsPharmacokinetics: the Adverse Effects of Heparin • INCREASES the clotting time and also DECREASES

the platelet count. In this regard, monitoring of the aPTT/PTT (N= 20-30 seconds) and platelet count is required.

• Hematologic effects: increased bleeding, thrombocytopenia

• Skin-itching and burning• Hypersensitivity reactions like chills, fever, urticaria or

anaphylaxis can occur since heparin is obtained from animal sources.

• Life threatening adverse effect is Hemorrhage

Heparins

The Nursing process and HeparinAssessment• Patient history• Physical examination- the nurse obtains

baseline vital signs and physical assessment.

• She must obtain laboratory results of the complete blood count, platelet count and activated partial thromboplastin time (aPTT), and clotting time.

Heparins

IMPLEMENTATION:• Monitor the aPTT closely (it should be 1.5-2.5

times normal value) • Monitor vital signs and hematological status

regularly. • Monitor signs of bleeding- hematuria,

epistaxis, ecchymoses, Hypotension and occult blood in stool

• Have available ANTIDOTE for heparin- PROTAMIME SULFATE

Heparins

IMPLEMENTATION:• Instruct the client not to use any over the

counter drug without notifying the physician• Administer heparin subcutaneously in the

abdominal region, using a 25-28-gauge needle at a 90-degree angle. DO NOT MASSAGE OR RUB THE AREA as this may cause bruising.

• Advise patient not to smoke, use electric razors to shave, use soft toothbrush and control sudden hemorrhage by direct pressure for 5-10 minutes.

• Provide gently skin and oral care.

Heparins

Evaluation• Monitor the effectiveness of the medication:

– Decreased formation of clot– PTT is 2x the normal

The Oral Anticoagulants

There are three commonly used oral anticoagulant agents in the hospital

• Warfarin- most commonly used, synthesized from dicumarol

• Dicumarol• Anisindone


Pharmacodynamics: the mechanism of Action of the Oral agents

• These agents INHIBIT the liver synthesis of the Vitamin K clotting factors – factors II, VII, IX, and X.


Clinical indications of oral anticoagulants• These drugs are used to prevent blood

clotting in patients with thrombophlebitis• pulmonary embolism and embolism from

atrial fibrillation.• Because Warfarin crosses the placental

barrier, it is NOT given to pregnant mothers.


Contraindications and precautions• Oral anti-coagulants are NOT given to

patients with bleeding disorders, peptic ulcers, severe renal/liver diseases, hemophilia, CVA blood dyscrasias and eclampsia.

• It is NOT given to pregnant mothers because it is teratogenic and can cause abortion


Pharmacokinetics:

• Oral anticoagulants prolong the clotting time and are monitored by the Prothrombine Time (PT- average of 9-12 seconds). This is usually performed before administering the next dose. The PT level should be 1.5-2 times the reference value to be therapeutic.

• The normal INR is 1-2. If the patient is on oral anticoagulant therapy, the INR is maintained at an INR of 2.0-3.0. If the INR is below the recommended range, warfarin is increased. If it is above the recommended range, warfarin should be reduced.


Pharmacokinetics: the Adverse Effects of Warfarin– Hematologic effects: increased bleeding,

thrombocytopenia– Anorexia, nausea, vomiting, diarrhea,

abdominal cramps, rash and fever.– Alopecia, bone marrow depression, and

dermatitis.– Life threatening adverse effect is

Hemorrhage


The Nursing process and Warfarin

Assessment• Patient history-. The nurse determines the

current medications taken, PREGNANCY, and history of recent surgery.

• Physical examination- the nurse obtains baseline vital signs and physical assessment.

• laboratory results of the complete blood count, platelet count and Prothrombin time, INR and clotting time.


Implementation• Monitor vital signs and hematological status• Monitor signs of bleeding- hematuria,

epistaxis, black tarry stools, echymoses, Hypotension and occult blood in stool

• Have available ANTIDOTE for warfarin- VITAMIN K or phytonadione.


Implementation• Advise patient not to smoke, use electric

razors to shave, use soft toothbrush and control sudden hemorrhage by direct pressure for 5-10 minutes. Provide gently skin and oral care.

• Instruct the patient to avoid foods high in vitamin K like spinach, nuts


Evaluation• Monitor the effectiveness of the medication

– Decreased formation of blood clots• Check the PT and INR

– Should be 2x the normal

Anti-platelets

These are agents decrease the formation of the platelet plug by decreasing the responsiveness of the platelets to various stimuli that would cause them to stick and combine together on a vessel wall– Aspirin– Dipyridamole– Sulfinpyrazone– Ticlopidine– Clopidogrel– Glycoprotein receptor antagonists

• Abciximab• Eptifibatide• Tirofiban

Anti-platelets

The mechanism of action of platelet inhibitors

• These agents INHIBIT the aggregation of platelets in the clotting process by blocking receptor sites on the platelet membrane, preventing platelet-to-platelet interaction, thereby prolonging the bleeding time.

Anti-platelets

Clinical indications• Prevention of myocardial infarction and

stroke• Prevention of a repeat myocardial infarction• Prevention of stroke for those with transient

ischemic attack• In patients with graft to maintain its patency.

Anti-platelets

Pharmacodynamics: the adverse effects of Antiplatelets

• Bleeding is the most common side effect• GIT- gum bleeding, gastric bleeding, tarry

stools• CNS- headache, dizziness and weakness• Skin- petechiae, bruising, allergy• ASPIRIN toxicity: tinnitus

Anti-platelets

Nursing considerations• Determine if the patient is allergic or sensitive

to the medications• Monitor closely the vital signs and bleeding

areas• Instruct the patient to take drug with food • Monitor the bleeding time, clotting time and

platelet count

Anti-platelets

Nursing considerations• Suggest safety measures including the use of

an electric razor and avoidance of contact sports.

• Provide increased precautions against bleeding during invasive procedures.

• Use pressure dressings and ice to decrease excessive blood loss.

• Monitor for tinnitus

The Thrombolytics

These thrombolytic agents are used to activate the natural anticlotting fibrinolytic mechanism to convert plasminogen to plasmin, which destroys and breaks down the fibrin threads in the blood clot (FIBRINOLYSIS). The result is clot disintegration.

The commonly used thrombolytics “---ase”• Streptokinase• Urokinase• Tissue plasminogen activator (t-PA) or alteplase• Anistreplase• Reteplase

The Thrombolytics

The mechanisms of actions of each agent• Streptokinase and urokinase are ENZYMES that act

SYSTEMICALLY to dissolve the blood clots by activating plasminogen to plasmin.

The Thrombolytics

Clinical indications of thrombolytics• Myocardial infarction• Pulmonary embolism• Thromboemboilic stroke• Peripheral arterial thrombosis and • to open clotted IV catheters.

The Thrombolytics

Pharmacokinetics: The adverse effects of Streptokinase

• CVS- Hypotension and dysrhythmias (usually upon reperfusion of the heart)

• Hematological: increased bleeding- the most common effect.

• Headache, nausea, flush, rash and fever• Allergic reaction- especially steptokinase and

urokinase• Major adverse effect- hemorrhage.

The Thrombolytics

Implementation.• Monitor signs of active bleeding from mouth and

rectum bleeding- hematuria, epistaxis, echymoses• Have available ANTIDOTE for thrombolytics:

AMINOCAPROIC ACID! • Have available blood for emergency use. • Advise patient not to smoke, use electric razors to

shave, use soft toothbrush and control sudden hemorrhage by direct pressure for 5-10 minutes.

• Provide gently skin and oral care. As much as possible, avoid frequent venipuncture.

The Thrombolytics

Evaluation• Monitor the effectiveness of the medication

– Clot lysis

The Agents to treat bleeding

• Aminocaproic acid and tranexamic acid– These are fibrin stabilizers that maintain or

stabilize the clot in the bleeding vessels


• Protamine sulfate– This agent antagonizes the anticoagulant

effects of heparin. It is derived from fish testis and is high in arginine content.

– The positive charge interacts with the negative charge of heparin to forma stable inactive complex.


• Vitamin K– Vitamin K is given to antagonize the effects of

the oral anticoagulants. – The response to Vitamin K is slow, requiring

about 24 hours– thus, if immediate hemostasis or bleeding

control is required, fresh frozen plasma should be ordered by the physician.

AntihyperlipidemicsThese drugs target the problem of elevated serum lipids• Resins and bile acid sequestrants

– Cholestyramine– Colestipol

• Fibric Acid Derivatives– Clofibrate– Gemfibrozil– Fenofibrate

• HMG CoA reductase inhibitors= “statins”– Atorvastatin– Cerivastatin– Fluvastatin– Lovastatin– Pravastatin– Simvastatin

• Nicotinic acid• Probucol

statins

Pharmacodynamics: The mechanism of action of the Statins

• These agents INHIBIT the enzyme HMG CoA reductase in the synthesis of cholesterol.

• By inhibiting the important enzyme in cholesterol production in the liver, the statins decrease the plasma concentration of cholesterol and lower the LDL level with slight increase in the HDL level.

statins

Therapeutic indications• These agents are given to patients with

CORONAY ARTERY DISEASE and hyperlipidemia, hypercholesterolemia

• These statins are very effective in all types of hyperlipidemias.

The antianemics: Iron preparations and Epoetin

Iron preparations• Iron is important for hemoglobin formation.

The iron preparations are:• Ferrous sulfate• Ferrous fumarate• Ferrous gluconate


Side-effects: GIT- constipation (usually), diarrhea, vomiting,

epigastric pain, gastric ulceration and darkening of stools.

• Liquid preparation can stain the teeth, and injectable iron can cause tissue discoloration

• Other- dizziness


Drug-Drug interaction• Tetracyclines and penicillamine- combine with iron

preparations and render the iron unabsorbable. • Antacids and cimetidine- decrease iron absorption

and effects• Foods can impair iron absorption but they should

be taken with iron to reduce GI discomfort. • Milk containing foods, coffee, tea and eggs are

NOT given with iron because they delay iron absorption.


Implementation• Encourage the patient to eat iron-rich foods like liver, lean

meat, egg yolk, dried beans, green leafy vegetables.• Administer iron preparations orally with foods to decrease GI

discomfort. • If increased absorption is necessary, administer IN BETWEEN

meals with full glass of water or juice. • It is best to offer citrus juices because the vitamin C

content can increase iron absorption. • Instruct the patient to swallow the whole tablet and remain

upright for 30 minutes to prevent esophageal corrosion from reflux.

• DO NOT administer iron together with or within 1 hour of ingesting tetracyclines, antacids, milk and milk-containing products.

• Advise clients to increase fluid intake and consume fiber rich foods if constipation becomes a problem.


Implementation• Warn the patient of possible iron poisoning if tablets

are left within child’s reach. Emphasize that the therapeutic effect of iron therapy may not be apparent until several weeks.

• If injecting a parenteral iron preparation, inject DEEP IM utilizing the Z-track method to avoid leakage into the subcutaneous tissues and skin.

• Offer straw if giving liquid iron preparation to avoid staining the teeth.

• To prevent undue alarm, instruct the patient that the stools may turn black or dark green. This is a harmless occurrence.


Evaluation• The nurse evaluates the effectiveness of the

drug therapy by determining that the client is not fatigued, with absence of pallor, and with hemoglobin results within desired range.

ErythropoietinThe mechanism of action of epoetin alfa

(Epogen)

• This drug acts like the natural glycoprotein erythropoietin to stimulate the production of RBC in the bone marrow.

Erythropoietin

Clinical indications

• It is given SUBCUTANEOUSLY or INTRAVENOUSLY for the treatment of anemia associated with renal failure or for patients on dialysis.

• It is also used in patients for blood transfusion to decrease the need for blood in surgical patients.

Erythropoietin

Pharmacodynamics: the adverse effects of epoetin alfa

• CNS- headache, fatigue, asthenia, dizziness and seizures- these are due to the cellular response to the glycoprotein.

• GIT- nausea, vomiting and diarrhea

• CVS- hypertension, edema and chest pain due to increase RBC number

ErythropoietinImplementation• Administer the drug SC or IV usually 3 times per week.• Monitor the IV access line if given IV. Do not mix with

other solutions• Determine periodically the level of hematocrit and iron

stores during therapy. If patient does not respond to the drug, reevaluate the cause of anemia.

• Maintain seizure precaution on stand by as seizure can occur.

• Provide comfort measures like small frequent feedings and pain medications for headache.

• Provide thorough health teaching: need for lifetime injection

Erythropoietin

Evaluation

• Monitor patient response to the drug= increased hemoglobin

pharmacology - hematologic drugs

Documents

oral agents

heparin chain

heparin factor

oral anticoagulantsthere

oral anticoagulant agents

oral care

blood clotting

adverse effects of heparin