ACETAZOLAMIDE

ACTION
Carbonic anhydrase inhibitor. This the enzyme that catalyzes the reversible reaction involving the hydration of carbon dioxide and the dehydration of carbonic acid.

INDICATIONS

  • Diuretic (particularly in the presence of metabolic alkalosis)
  • Correction of severe metabolic alkalosis

COMES AS

  • PO / NG:
    • 250mg tablets (white); for NG use, crush prior to administration.
  • IV:
    • Each vial contains 500 mg of acetazolamide.

Dilute 500-mg vial containing acetazolamide should be reconstituted with at least 5 ml of sterile water for injection prior to use.


DOSAGE

  • For diuresis – 250-375 mg stat.
    • If, after an initial response, the patient fails to continue to diurese, do not increase the dose but allow for kidney recovery by skipping medication for a day. Acetazolamide yields best diuretic results when given on alternate days, or for 2 days alternating with a day of rest.

WARNINGS AND PRECAUTIONS

  • Hypersensitivity to acetazolamide or other sulphonamides
  • Metabolic acidosis
  • Cirrhosis (risk of development of hepatic encephalopathy)
  • RARE
    • Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias.
  • Modifies phenytoin metabolism with increased serum levels of phenytoin.
  • Increases lithium excretion and the lithium levels may be decreased.
  • Acetazolamide and sodium bicarbonate used concurrently increases the risk of renal calculus formation.
  • May elevate cyclosporine levels.

ACETYLCYSTEINE

ACTION

Given for paracetamol O.D. Acetylcysteine likely protects the liver by maintaining or restoring the glutathione levels, or by acting as an alternate substrate for conjugation with, and thus detoxification of, the reactive metabolite.

INDICATIONS

  • Paracetamol overdose
  • Non-paracetamol induced fulminant hepatic failure
  • NOT recommended for use as a preventative agent in contrast-induced nephropathy.

COMES AS

  • IV
    • 10ml vials containing 20% (200 mg/ml) acetylcysteine.
    • Compatible with 5% dextrose.

DOSAGE

  • Paracetamol Overdose:
    • Initial – 150mg/kg in 200ml 5% dex over 15 minutes
    • 2nd – 50mg/kg in 500ml 5% dex over 4 hours
    • 3rd – 100mg per kg in 1000ml 5% dex over 16 hours
    • Total dose 300mg/kg in 20 hours

WARNINGS AND PRECAUTIONS

  • General
    • The total volume administered should be adjusted for patients less than 40 kg and for those requiring fluid restriction

ACYCLOVIR

ACTION
Synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV).

INDICATIONS

  • Herpes Simplex encephalitis
  • Prophylaxis in an allogeneic bone marrow transplant patient (at risk of CMV)
  • Varicella Pneumonia
  • Uncomplicated Herpes Simplex or Varicella Zoster infection in an immunocompromised patient.
  • Treatment of Shingles

COMES AS

  • PO / NG
    • 200mg, 400mg and 800mg tablets
    • 200mg dispersible tablets are also available
  • IV
    • Vial containing 250mg in 10ml.
    • 25mg/ml solution via a controlled rate infusion pump over at least one hour (preferred method if administering via a central line)
    • OR: dilute 25mg/ml solution to make a solution of 5mg/ml using a compatible IV fluid (eg dilute 5ml into 25ml total) and then administer by controlled infusion over at least one hour (preferred method if administering via a peripheral line)
  • TOP
    • Each gram of Zovirax cream 5% contains 50 mg acyclovir in an aqueous cream base. It is supplied in 2 g tubes.

DOSAGE

  • Herpes Simplex Encephalitis
    • 10 mg/kg IV infused at a constant rate over 1 hour, every 8 hours for 10 days.
  • Herpes Simplex Infections in Immunocompromised Patients
    • 5 mg/kg IV infused at a constant rate over 1 hour, every 8 hours for 7 days.
  • Varicella Zoster Infections including Varicella Pneumonia
    • 10 mg/kg IV infused at a constant rate over 1 hour, every 8 hours for 7 days.
  • Uncomplicated Shingles in the non-immunocompromised patient
    • 800 mg five times daily for 10 days (There are no data on treatment initiated more than 72 hours after onset of the zoster rash.)
  • Cold sores (in the non-immunocompromised)
    • Acyclovir cream should be applied 5 times per day for 4 days. Therapy should be initiated as early as possible following onset of signs and symptoms. 

NOTE: IV therapy is indicated in the immunocompromised and in patients with Varicella pneumonia


ADENOSINE

ACTION
Adenosine slows conduction time through the A-V node, can interrupt the reentry pathways through the AV node and can restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT), including PSVT associated with Wolff-Parkinson-White Syndrome. Half life is barely more than 10 seconds, thus adverse effects normally rapidly terminate.

INDICATIONS

  • Paroxysmal supraventricular tachycardia (PSVT)
  • PSVT with accessory bypass tracts (Wolff-Parkinson-White Syndrome)

COMES AS

  • IV
    • 6mg in 2mls solution

DOSAGE

Rapid bolus by the peripheral IV route followed by a rapid saline flush 
The recommended IV doses for adults are as follows:

  • Initial dose:
    • 6 mg IV over 1-2 seconds
  • Repeat administration:
    • 12 mg IV over 1-2 seconds 

WARNINGS AND PRECAUTIONS

  • Second- or third-degree A-V block (except in patients with a functioning artificial pacemaker).
    • Patients who develop high-level block on one dose of adensoine should not be given additional doses. Because of the very short half-life of adenosine, these effects are generally self-limiting.
  • Sinus node disease, such as sick sinus syndrome or symptomatic bradycardia (except in patients with a functioning artificial pacemaker).
  • Asystole and VF
    • In most instances, these cases were associated with the concomitant use of digoxin and, less frequently with digoxin and verapamil.As a result, adenosine should be used with caution in patients receiving digoxin or digoxin and verapamil in combination.
  • Arrhythmias at Time of Conversion
    • At the time of conversion to normal sinus rhythm, a variety of new rhythms may appear on the electrocardiogram. They generally last only a few seconds without intervention, and may take the form of premature ventricular contractions, atrial premature contractions, sinus bradycardia, sinus tachycardia, skipped beats, and varying degrees of A-V nodal block. Such findings are seen in 55% of patients.
  • Bronchoconstriction
    • Adenosine has been administered to a limited number of patients with asthma and mild to moderate exacerbation of their symptoms has been reported. Adenosine should be used with caution in patients with obstructive lung disease or asthma. Adenosine should be discontinued in any patient who develops severe respiratory difficulties.
  • Body as a Whole:
    • Apprehension, facial flushing, sweating
  • Cardiovascular System:
    • Palpitations, chest pain, hypotension
  • Respiratory System:
    • Bronchospasm, shortness of breath/dyspnea, chest pressure
  • Digestive System:
    • Nausea, metallic taste, tightness in throat, pressure in groin.
  • Nervous System:
    • Lightheadedness, dizziness, tingling in arms, numbness, blurred vision, burning sensation

ADRENALINE

ACTION
Direct acting catecholamine sympathomimetic with effect on both α and β receptors equally.

The effects of adrenaline include:

  • HR – Increase in heart rate, force of contraction and conduction velocity
  • BP – Systolic pressure is increased but diastolic pressure may drop due to β2 mediated vasodilatation.
  • Vessels – At higher doses effects on α1 receptors in peripheral blood vessels becomes predominant and peripheral resistance is increased.
  • Airway – Effects on β2 receptors causes bronchodilatation
  • Blood – Increases platelet adhesiveness and blood coagulability by increasing the activity of factor V.
  • Renal – Decreases renal blood flow by up to 40% although GFR is often preserved.
  • Metabolic – Decreases insulin secretion and increases glucagon secretion. Plasma rennin activity is increased via a β2 effect. Plasma free fatty acid levels are increased by activation of triglyceride lipase.

INDICATIONS

  • Cardiac arrest
  • Anaphylaxis
  • Upper airway obstruction
  • Inotrope / vasopressor

COMES AS

  • IV
    • Vials containing 1mg in 1ml (1:1000)
    • Vials containing 1mg in 10ml (1:10000)
    • Mini-jets containing 1mg in 10ml
  • IM
    • Use 1:1000 solution undiluted for administration by the IM route.

***Notes on infusion

The standard dilution for adrenaline by infusion in the ICU is 10mg in 100ml of compatible IV fluidTypical starting dose 0.01 micrograms/kg/minute. Titrate the infusion rate to target MAP. Adrenaline MUST be administered via a syringe driver through a central venous catheter. Peripheral veins should NOT be used.

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DOSAGE

ADULT DOSE

  • Cardiac arrest
    • IV – 10ml of 1:10000 (i.e 1mg). Give bolus doses of 1ml of 1:10000 and uptitrate gently if circulation is not restored.
    • Down ETT – 3-10mg of 1:1000
  • Anaphylaxis
    • IV – .5-1ml of 1:10000 IV with dose titrated to effect followed by IV infusion if required.
    • IM – 0.5-1ml of 1:1000 IM
  • Post-extubation stridor or other upper airway obtruction:
    • 1:1000 vial, make up to max. dose 5ml and administer via a nebuliser
  • IV Infusion
    • 10mg in 100ml of D5W or normal saline at up to 20ml/hr titrated to effect

ADVERSE REACTIONS

  • Body as a Whole:
    • Apprehension, nervousness, anxiety and sweating.
  • Cardiovascular System:
    • Palpitations, tachycardia, pallor.
  • Respiratory System:
    • Hyperventilation, pulmonary oedema
  • Digestive System:
    • Nausea and vomiting,
  • Nervous System:
    • Headache, tremor, dizziness, weakness, cerebrovascular haemorrhage

ALFENTANIL

ACTION

Opiate receptors are coupled with G-protein receptors and binding of the opiate stimulates the exchange of GTP for GDP on the G-protein complex. This decreases intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine and noradrenaline is inhibited. Opioids also inhibit the release of vasopressin, somatostatin, insulin and glucagon.

Alfentanil’s analgesic activity is, most likely, due to its conversion to morphine. Opioids close N-type voltage-operated calcium channels (OP2-receptor agonist) and open calcium-dependent inwardly rectifying potassium channels (OP3 and OP1 receptor agonist). This results in hyperpolarization and reduced neuronal excitability.

COMES AS

  • 1mg in 2mL
  • 5mg in 1ml
  • 5mg in 10mL

 


DOSAGE

  • Painful procedures
    • 5-10mcg/kg IV (approx 250-500mcg)
  • Sedation

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ALLOPURINOL

ACTION

  • Allopurinol is a structural analogue of the natural purine base, hypoxanthine.
  • Inhibitor of xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and of xanthine to uric acid, the end product of purine metabolism in man.
  • Allopurinol is approximately 90% absorbed from the gastrointestinal tract.

ROUTE

  • PO, NG

ICU INDICATIONS:

1. Prophylaxis against gout
2. The management of patients with leukaemia, lymphoma and malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels.

PRESENTATION AND ADMINISTRATION:

  • 100mg and 300mg tablets (white); tablets may be crushed and administered via the nasogastric tube.

DOSAGE:

  • Gout:

The minimal effective dosage is 100-200 mg daily and the maximal recommended dosage is 800 mg daily. The appropriate dosage may be administered in divided doses or as a single equivalent dose with the 300 mg tablet. Dosage requirements in excess of 300 mg should be administered in divided doses.

  • Prevention of hyperuricaemia in patients at risk of tumour lysis syndrome:

For the prevention of uric acid nephropathy during the vigorous therapy of neoplastic disease, treatment with 600-800 mg daily for 2-3 days is advisable together with a high fluid intake.


DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose in renal impairment [GFR (ml/min)]

<10 100mg daily / alternate days 10-20 100-200mg daily
>20-50 200-300mg/daily
Dose in renal replacement therapy

CONTRAINDICATIONS:

1. Hypersensitivity to allopurinol

WARNINGS
The most frequent adverse reaction to allopurinol is skin rash. Skin reactions can be severe and sometimes fatal. Therefore, treatment with allopurinol should be discontinued immediately if a rash develops.

 

 

AMINOPYLLINE

ACTION
After ingestion, theophylline is released from aminophylline, and theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels and reduces airway responsiveness to histamine, methacholine, adenosine, and allergen. Theophylline competitively inhibits type III and type IV phosphodiesterase (PDE), the enzyme responsible for breaking down cyclic AMP in smooth muscle cells, possibly resulting in bronchodilation. Theophylline also binds to the adenosine A2B receptor and blocks adenosine mediated bronchoconstriction. In inflammatory states, theophylline activates histone deacetylase to prevent transcription of inflammatory genes that require the acetylation of histones for transcription to begin. It has also been demonstrated that aminophylline has a potent effect on diaphragmatic contractility in normal persons and may then be capable of reducing fatigability and therapy improve contractility in patients with chronic obstructive airway disease.

INDICATIONS

  • Management of acute life threatening asthma
  • Long term treatment for emphysema and chronic bronchitis

COMES AS

  • IV
    • 250mg/10ml (solution)
    • For adult administration dilute 500mg in 500ml of compatible IV fluid to make a concentration of 1mg/ml.

DOSAGE

  • Asthma and COPD
    • 0.5-1mg/kg/hr (usually 0-40ml/hr)

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ADVERSE EFFECTS

  • Body as a Whole
    • Irritability, restlessness, insomnia
  • Cardiovascular System
    • Palpitation, tachycardia, extrasystoles, flushing, hypotension, circulatory failure, ventricular arrhythmias
  • Respiratory System
    • Tachypnoea
  • Digestive System
    • Nausea, vomiting, epigastric pain, haematemesis, diarrhoea.
  • Nervous System
    • Headaches, reflex hyperexcitability, muscle twitching, clonic and tonic generalized convulsions.

AMIODARONE

ACTION

An antianginal and antiarrhythmic drug. Amiodarone belongs to a class of drugs called Vaughan-Williams Class III antiarrhythmic agents (spans all 4 classes however). It is used in the treatment of a wide range of cardiac tachyarhthmias, including both ventricular and supraventricular (atrial) arrhythmias. After intravenous administration in man, amiodarone relaxes vascular smooth muscle, reduces peripheral vascular resistance (afterload), and slightly increases cardiac index. Amiodarone prolongs phase 3 of the cardiac action potential, slowing heart rate. It has numerous other effects however, including actions that are similar to those of antiarrhythmic classes Ia, II, and IV. Amiodarone shows beta blocker-like and calcium channel blocker-like actions on the SA and AV nodes, increases the refractory period via sodium- and potassium-channel effects, inhibiting Na,K-activated myocardial adenosine triphosphatase.

INDICATIONS

  • VT
  • VF
  • Atrial tachycardias
  • AF

COMES AS

  • PO / NG
    • 200mg tablets; tablets may be crushed for NG administration
  • IV
    • 150mg in 3ml vials.
    • For stat dose (usually 300mg) add to a standard 100ml plastic bag of D5W.

DOSAGE

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  • Transition from IV to oral therapy
    • 200mg PO 8 hourly for 1 week followed by 200mg PO 12 hourly for one week followed by 200mg PO 12-24 hourly thereafter

Note – higher oral dosages (up to 1600mg per day can be used in patients who have not received a full IV load). An overlap of intravenous and oral medication of up to two days is recommended.


WARNINGS

  • Hypotension
    • Hypotension is the most common adverse effect seen with amiodarone. Hypotension should be treated by vasopressor drugs, positive inotropic agents, and volume expansion. Slowing the rate of infusion may also be effective.
  • Bradycardia and AV Block
    • Drug-related bradycardia should be treated by discontinuing amiodarone. Additional measures including drug therapy and/or temporary pacing may be required if bradycardia does not resolve.

ADVERSE REACTIONS

  • Body as a Whole:
    • Fever
  • Cardiovascular System:
    • Bradycardia, congestive heart failure, hypotension, ventricular tachycardia
  • Respiratory System:
    • Dyspnea, cough, haemoptysis, wheezing, hypoxia, pulmonary infiltrates
  • Digestive System:
    • Nausea, deranged LFTs
  • Nervous System:
    • Hallucinations, confusional state, pseudotumour cerebri
  • Endocrine System:
    • Hypothyroidism, hyperthyroidism, SIADH
  • Skin:
    • Toxic epidermal necrolysis

 

AMITRYPTILLINE

ACTION

  • TCAs are potent inhibitors of serotonin and norepinephrine reuptake.
  • Tertiary amine TCAs, such as amitriptyline, are more potent inhibitors of serotonin reuptake than secondary amine TCAs, such as nortriptyline.
  • TCAs also down-regulate cerebral cortical β-adrenergic receptors and sensitize post-synaptic serotonergic receptors with chronic use.
  • The antidepressant effects of TCAs are thought to be due to an overall increase in serotonergic neurotransmission. TCAs also block histamine-H1receptors, αadrenergic receptors and muscarinic receptors, which accounts for their sedative, hypotensive and anticholinergic effects (e.g. blurred vision, dry mouth, constipation, urinary retention), respectively.

ROUTE

PO, NG

INDICATIONS

1. Neurogenic pain (eg GBS)

2. Nocturnal sedation

DOSAGE

  • Neurogenic pain and nocturnal sedation in the ICU:

Commence at 10mg at night; increase to 25mg to 50mg as tolerated
Note – the usual dose for treatment of depression is up to 75-300mg per day (this dose is rarely appropriate in ICU patients)

CONTRAINDICATIONS

  • Hypersensitivity to amitriptyline
  • Should not be given concomitantly with monoamine oxidase inhibitors.

 

AMLODIPINE

ACTIONS
Amlodipine is a dihydropyridine calcium channel blocker. It does not cause significant negative inotropy. Peak plasma concentrations occur between 6 and 12 hours after oral administration, so it rarely causes acute hypotension.

  • Dilates peripheral arterioles acting on their smooth muscle. Reduces total peripheral resistance (afterload) against which the heart works.
    • Since the heart rate remains stable, this unloading of the heart reduces myocardial energy consumption and oxygen requirements.
  • Dilates main coronary arteries and coronary arterioles, both in normal and ischaemic regions. This dilation increases myocardial oxygen delivery in patients with coronary artery spasm (Prinzmetal’s or variant angina).
    • In patients with angina, once daily administration of amlodipine increases total exercise time, time to angina onset, and time to 1mm ST segment depression, and decreases both angina attack frequency and glyceryl trinitrate tablet consumption.

INDICATIONS

  • Hypertension
  • Afterload reduction
  • Angina refractory to nitrate therapy (rarely used for this)

COMES AS

  • Oral
    • 5mg and 10mg

DOSAGE

  • 5-10mg OD

WARNINGS

  • Increased Angina and/or Myocardial Infarction
    • Rarely, patients, particularly those with severe obstructive coronary artery disease, have developed documented increased frequency, duration and/or severity of angina or acute myocardial infarction on starting calcium channel blocker therapy or at the time of dosage increase. The mechanism of this effect has not been elucidated.

ADVERSE REACTIONS

  • Body as a Whole:
    • Allergic reaction, back pain, hot flushes, malaise, pain, rigors, weight gain, weight decrease.
  • CVS
    • Arrhythmia (including ventricular tachycardia and atrial fibrillation), bradycardia, chest pain, hypotension, peripheral ischemia, syncope, tachycardia, postural dizziness, postural hypotension, vasculitis.
  • GIT
    • Anorexia, constipation, dyspepsia, dysphagia, diarrhoea, flatulence, pancreatitis, vomiting, gingival hyperplasia.
  • CNS
    • Hypoesthesia, neuropathy peripheral, paraesthesia, tremor, vertigo.
  • Skin
    • Angioedema, erythema multiforme, pruritus, rash.
  • RS
    • Dyspnea, epistaxis
  • Musculoskeletal System
    • Arthralgia, arthrosis, muscle cramps, myalgia

AMOXICILLIN

ACTIONS
Amoxicillin is a semisynthetic penicillin (beta-lactam antibiotic) that inhibits one or more enzymes (often referred to as penicillin-binding proteins, PBPs) in the biosynthetic pathway of bacterial peptidoglycan, which is an integral structural component of the bacterial cell wall. Inhibition of peptidoglycan synthesis leads to weakening of the cell wall, which is usually followed by cell lysis and death. Diffuses into most body tissues and fluids but not CSF unless meninges are inflamed.

Amoxicillin is susceptible to degradation by beta-lactamases produced by resistant bacteria and therefore the spectrum of activity of amoxicillin alone does not include organisms which produce these enzymes.

Will Kill:

  • Aerobic Gram-Positive Microorganisms:
    • Enterococcus faecalis / Staphylococcus spp*. (beta-lactamase-negative strains only) / Streptococcus pneumoniae / *Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.
  • Aerobic Gram-Negative Microorganisms:
    • Escherichia coli (beta-lactamase-negative strains only) / Haemophilus influenzae (beta-lactamase-negative strains only) / Neisseria gonorrhoeae (beta-lactamase-negative strains only) / Proteus mirabilis (beta-lactamase-negative strains only).

COMES AS

  • IV
    • 1g vial (powder). Dilute to total of 5ml if part dose is required (making concentration of 200mg/ml). Inject slowly over 3-4 minutes or in 100ml of compatible fluid over 30-60 minutes
  • PO
    • 250mg tablets & 500mg tablets
    • Suspension (125mg/5ml and 250mg/ml)

 


DOSAGE

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ADVERSE REACTIONS

  • Body as a Whole:
    • Serum sickness like reactions, Anaphylaxis
  • Digestive System:
    • Nausea, vomiting, diarrhoea, and haemorrhagic/pseudomembranous colitis. Hepatic dysfunction including cholestatic jaundice, hepatic cholestasis and acute cytolytic hepatitis have been reported.
  • Nervous System:
    • Reversible hyperactivity, agitation, anxiety, insomnia, confusion, convulsions, behavioral changes, and/or dizziness have been reported rarely.
  • Skin:
    • Stevens-Johnson Syndrome, exfoliative dermatitus, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, hypersensitivity vasculitis and urticaria have been reported
  • Haematological System:
    • Anaemia, including haemolytic anaemia, thrombocytopaenia, thrombocytopenic purpura, eosinophilia, leukopaenia, and agranulocytosis have been reported during therapy with penicillins.

ASPIRIN

ACTIONS

Aspirin is a salicylate that has demonstrated antiplatelet, antiinflammatory, analgesic and antipyretic activity.

  • Anti platelet effect
    • Low doses (typically 75 to 81 mg/day) are sufficient to irreversibly acetylate serine 530 of cyclooxygenase (COX)-1. This effect inhibits platelet generation of thromboxane A2 (platelet aggregating agent), resulting in an antithrombotic effect.
    • Since platelets lack the ability to synthesize new proteins, the effects persist for the life of the exposed platelets (7-10 days). Acetylsalicylic acid may also inhibit production of the platelet aggregation inhibitor, prostacyclin (prostaglandin I2), by blood vessel endothelial cells; however, inhibition prostacyclin production is not permanent as endothelial cells can produce more cyclooxygenase to replace the non-functional enzyme.
  • Analgesic effect
    • Intermediate doses (650 mg to 4 g/day) inhibit COX-1 and COX-2, blocking prostaglandin (PG) production, and have analgesic and antipyretic effects.

INDICATIONS

 

COMES AS

  • PO:
    • 75 and 300mg tablets (non-enteric coated)
    • Aspirin Ethics 100mg (enteric coated)

DOSAGE

  • Anti platelet effect:
    • 75/150/300mg NG/PO OD
  • Analgesic effect:
    • 625mg-1g PO/NG QDS

ADVERSE REACTIONS

  • Hypersensitivity to aspirin!
  • Gastrointestinal bleeding!
  • Body as a Whole:
    • Headache and fever, anaphylaxis.
  • Digestive System:
    • Dyspepsia, thirst, nausea, vomiting, diarrhoea, acute reversible hepatotoxicity, gastrointestinal bleeding, and/or ulceration.
  • Nervous System:
    • Mental confusion, drowsiness, and dizziness
  • Skin:
    • Urticaria, angioedema, and pruritus.
  • Haematological System:
    • Prolongation of bleeding time, leukopaenia, thrombocytopaenia, purpura, decreased plasma iron concentration and shortened erythrocyte survival time.
  • Special Senses:
    • Tinnitus, vertigo, reversible hearing loss, and dimness of vision.

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  • The lethal dose of acetylsalicylic acid is 25-30 grams. 
  • A toxic dose is about 200 mg/kg in adults and 100 mg/kg in children
  • Common features include
    • Vomiting, dehydration, tinnitus, vertigo, deafness, sweating, warm extremities with bounding pulses, increased respiratory rate and hyperventilation. Headache, nausea and abode pain also common.
  • Some degree of acid-base disturbance is present in most cases.
    • A mixed respiratory alkalosis and metabolic acidosis with normal or high arterial pH (normal or reduced hydrogen ion concentration) is usual in adults and children over the age of four years.
    • In children aged four years or less, a dominant metabolic acidosis with low arterial pH (raised hydrogen ion concentration) is common. Acidosis may increase salicylate transfer across the blood brain barrier.
  • Central nervous system features
    • including confusion, restlessness, hallucinations, disorientation, coma, cardiovascular collapse, respiratory arrest and convulsions 

Management

  • Hospital admission is required
  • Give activated charcoal if an adult presents within one hour of ingestion of more than 250 mg/kg.
  • The plasma salicylate concentration should be measured, although the severity of poisoning cannot be determined from this alone and the clinical and biochemical features must be taken into account.
  • Elimination is increased by urinary alkalinisation, which is achieved by the administration of 1.26% sodium bicarbonate.
    • The urine pH should be monitored.
    • Correct metabolic acidosis with intravenous 8.4% sodium bicarbonate (first check serum potassium).
    • Forced diuresis should not be used since it does not enhance salicylate excretion and may cause pulmonary oedema.
  • Haemodialysis is the treatment of choice for severe poisoning and should be considered in patients with plasma salicylate concentrations >700 mg/L (5.1 mmol/L), or lower concentrations associated with severe clinical or metabolic features. 
  • Other symptoms to be treated symptomatically.

 

ATENOLOL

ACTIONS
Atenolol is a beta 1-selective (cardioselective) beta-adrenergic receptor blocking agent without membrane stabilizing or intrinsic sympathomimetic (partial agonist) activities.  However, and at higher doses, atenolol inhibits beta 2-adrenoreceptors, chiefly located in the bronchial and vascular musculature. Peak blood levels are reached between 2 and 4 hours after ingestion. It has negative inotropic effects (and is therefore contraindicated in uncontrolled heart failure). It is probably the action of atenolol in reducing cardiac rate and contractility, which makes it effective in eliminating, or reducing the symptoms of patients with angina.

Early intervention with Atenolol in acute myocardial infarction reduces infarct size and decreases morbidity and mortality. Fewer patients with a threatened infarction progress to frank infarction; the incidence of ventricular arrhythmias is decreased and marked pain relief may result in reduced need of opiate analgesics. Early mortality is decreased. Atenolol is an additional treatment to standard coronary care.ICU INDICATIONS

 

INDICATIONS

  • Hypertension
  • Acute myocardial infarction
  • Secondary prevention in patients with coronary artery disease
  • Angina
  • Rate control

COMES AS

  • PO
    • 50mg and 100mg tablets. Tablets may be crushed and administered via nasogastric tube.

DOSAGE

  • Hypertension and dysrhythmias
    • Commence at 50mg daily; increase to 100mg daily as tolerated.
  • Myocardial Infarction
    • Initial – 5–10 mg should be given by slow intravenous injection (1 mg/minute)
    • 15 min later – 50 mg orally 
    • 12h later – 50 mg orally 
    • 24h hours later – 100 mg orally, once daily to continue. 

WARNINGS

  • Sinus bradycardia
  • Heart block greater than first degree
  • Cardiogenic shock
  • Overt cardiac failure
  • Asthma

ADVERSE REACTIONS

  • Body as a Whole:
    • Tiredness, Fatigue
  • Cardiovascular System:
    • Bradycardia , Cold extremities, Hypotension, Leg pain
  • Respiratory System:
    • Wheeziness, Dyspnoea
  • Digestive System:
    • Diarrhoea, Nausea
  • Nervous System:
    • Dizziness, Vertigo, Light-headedness

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  • The symptoms of overdosage may include bradycardia, hypotension, acute cardiac insufficiency and bronchospasm.
  • General treatment
    • Close supervision; treatment in an intensive care ward
    • Gastric lavage; activated charcoal and a laxative to prevent absorption of any drug still present in the gastrointestinal tract
    • Plasma or plasma substitutes to treat hypotension and shock. The possible uses of haemodialysis or haemoperfusion may be considered.
  • Excessive bradycardia
    • Atropine 1–2 mg intravenously and/or a cardiac pacemaker.
    • If necessary, this may be followed by a bolus dose of glucagon 10 mg intravenously.
    • If required, this may be repeated or followed by an intravenous infusion of glucagon 1–10 mg/hour depending on response.
    • If no response to glucagon occurs or if glucagon is unavailable, a beta-adrenoceptor stimulant such as dobutamine 2.5 to 10 micrograms/kg/minute by intravenous infusion may be given. Dobutamine, because of its positive inotropic effect could also be used to treat hypotension and acute cardiac insufficiency.
  • Bronchospasm can usually be reversed by bronchodilators.

AUGMENTIN

ACTIONS

(See Amoxicillin). Clavulanic acid is combined here to form Augmentin (Co-amoxiclav) a beta-lactam structurally related to penicillins. It inactivates some beta-lactamase enzymes thereby preventing inactivation of amoxicillin. This it is bactericidal. Clavulanic acid alone does not exert a clinically useful antibacterial effect.

Will Kill

  • Gram-Positive Aerobes:
    • Staphylococcus aureus (beta-lactamase and non-beta-lactamase producing).*
      *Staphylococci which are resistant to methicillin/oxacillin must be considered resistant to amoxicillin/clavulanic acid.
  • Gram-Negative Aerobes:
    • Enterobacter species. (Although most strains of Enterobacter species are resistant in vitro, clinical efficacy has been demonstrated with Augmentin in urinary tract infections caused by these organisms.) / Escherichia coli (beta-lactamase and non-beta-lactamase producing) / Haemophilus influenzae (beta-lactamase and non-beta-lactamase producing) / Klebsiella species (all known strains are beta-lactamase producing) / Moraxella catarrhalis (beta-lactamase and non-beta-lactamase producing).

COMES AS

  • IV
    • 600mg and 1.2gm vials (powder). Reconstitute by adding 10ml of water for injection to 600mg vial (final volume 10.5ml) or 20ml to 1.2gm vial (final volume 20.9 ml) and agitating until dissolved.
  • PO
    • 625mg (500mg amoxicillin, 125mg clavulanic acid) white tablets
    • Augmentin forte syrup 250 (250mg amoxicillin, 62.5mg clavulanic acid)

DOSAGE

  • IV
    • 1.2gm IV 8hrly
  • PO
    • 500mg/125mg PO 8hrly