EMT DRUGS REVISED Flashcards
adrenaline mechanism
- Adrenaline stimulates alpha and beta receptors, with the predominant effects occurring at alpha 1, beta 1 and beta 2 receptors.
- Alpha 1 stimulation causes smooth muscle contraction, vasoconstriction of blood vessels and stimulation of glycogenolysis and gluconeogenesis.
- Beta 1 stimulation causes an increase in inotropy (cardiac contractility), an increase in chronotropy (heart rate) and an increase in dromotropy (speed of electrical conduction within the heart).
- Beta 2 stimulation causes smooth muscle relaxation, skeletal muscle vasodilation, bronchodilation, and stabilisation of mast cell membranes, reducing histamine release.
adrenaline indication
EMT
Clinically significant epistaxis
Stridor causing moderate to severe respiratory distress
Anaphylaxis
Severe asthma
Clinically significant bleeding from a wound
Other indications
Cardiac arrest
Imminent respiratory arrest from COPD
Severe bradycardia
BP support if unresponsive to metaraminol
Septic shock, cardiogenic shock, and neurogenic shock, unresponsive to 0.9% sodium chloride IV and metaraminol IV
adrenaline contraindications
nil
adrenaline cautions
Myocardial ischaemia. Adrenaline will increase myocardial oxygen consumption.
Tachydysrhythmias. Adrenaline will usually make tachydysrhythmias wors
topical use of adrenaline
Topical: dilute each mg of adrenaline to a total of 10 ml using 0.9% sodium chloride. This solution is 1:10,000 and contains 0.1 mg/ml. Apply topically in addition to direct pressure.
IN admin of adrenaline
IN for epistaxis
drawup with 8mls sodium chloride
0.2 mg (2 mls) aged 12 and over
0.1 mg (1 mls) 5-11 years.
Repeat dose after 20 mins
IM adrenaline admin
IM for asthma/anaphylaxis
Undiluted
0.5 mg
repeat every 5 to 10 mins
Arrest adrenaline admin
Cardiac arrest: 1mg every 4 mins
a) Adults and children whose weight has been rounded to 50 kg or more: administer undiluted as an IV bolus.
b) Children whose weight has been rounded to 40 kg or less: dilute 1 mg of adrenaline to a total of 10 ml using 0.9% sodium chloride. This solution is 1:10,000 and contains 0.1 mg/ml. Draw up the dose from this solution and administer as an IV bolus.
common adverse affects of adrenaline
- Tachycardia.
- Tachydysrhythmia.
- Myocardial ischaemia.
- Ventricular ectopy.
- Hypertension.
- Nausea and vomiting.
- Tremor, anxiety and sweating.
- Hyperglycaemia.
usual onset of adrenaline
- IV: 5-10 seconds.
- IM: 2-5 minutes.
- Nebulised, IN and topical: on contact with the target site.
duration of adrenaline
- The cardiovascular effects last 5-15 minutes.
- The mast cell membrane effects may last for several hours.
pharmokinetics of adrenaline
- Adrenaline is metabolised by the liver and taken up by sympathetic nerve endings.
- There are no significant effects from liver impairment on acute administration.
common interactions with adrenaline
Increased doses may be required if the patient is taking a beta-blocker or a calcium channel blocker. This effect is particularly prominent in the setting of poisoning if a large dose of a beta-blocker and/or calcium channel blocker has been taken.
aspirin mechnism
Aspirin (acetylsalicylic acid) has antiplatelet, antipyretic, anti-inflammatory and analgesic effects. In the out-of-hospital setting aspirin is only administered for its antiplatelet activity.
* Aspirin inhibits the enzyme cyclooxygenase which results in a reduction in the formation of prostaglandins and thromboxane.
indication of aspirin
myocardial ischemia
contraindications of aspirin
Known severe allergy.
pregnancy
cautions of aspirin
^ Known bleeding disorder. Aspirin will increase the risk of bleeding, however the balance of risk is usually in favour of administering aspirin.
^ Clinically significant bleeding. Aspirin will increase the risk of bleeding and the nature and risk of the bleeding must be taken into account.
^ Known worsening of bronchospasm with NSAIDs. Some patients with asthma or COPD have known worsening of bronchospasm with NSAIDs (including aspirin) and a decision must be made based on the balance of risk. If there
is a clear history of significant bronchospasm with NSAIDs, aspirin should be withheld.
aspirin and pregnancy interactions
- May cause harm during pregnancy. Aspirin has been associated with premature delivery and premature closure of the ductus arteriosus, when administered in the third trimester of pregnancy.
- The likelihood of clinically important myocardial ischaemia occurring in a woman who is pregnant is so low that the balance of risk is usually in favour of aspirin being withheld.
- May be administered if the patient is breastfeeding. Advise the patient to stop breastfeeding and seek further advice from their lead maternity carer or GP
aspirin dosage
300mg
common adverse affects of aspirin
- Increased bleeding.
- Although indigestion, gastrointestinal ulceration and gastrointestinal bleeding are commonly listed as adverse effects, these are only associated with long- term administration.
usual onset of aspirin
- 30-60 minutes.
usual duration of aspirin
- 3-5 days for the antiplatelet activity. This is because platelets exposed to aspirin are impaired for the life of the platelet which is 7-10 days. Approximately 10% of platelets are replaced each day.
pharmokinetics of aspirin
- Absorption occurs in the stomach and small intestine. The presence of food in the stomach will delay absorption, but this is not usually clinically significant.
- Aspirin is predominantly metabolised in the liver.
- There are no significant effects from liver impairment on acute administration.
common interactions of aspirin
- Aspirin displaces warfarin from binding sites and increases the activity of warfarin. However, this effect is most prominent with chronic administration and aspirin is indicated if a patient taking warfarin has clinically significant myocardial ischaemia.
glucagon mechnism
- Glucagon increases the blood glucose level by stimulating glycogenolysis (the breakdown of glycogen into glucose), predominantly within the liver.
glucagon indication
Hypoglycaemia when the patient cannot safely swallow glucose/food and IV access cannot be obtained.
glucagon contraindications
Known severe allergy.
glucagon cautions
nil
glucagon dosage
- 1 mg IM once for an adult or child aged greater than or equal to five years.
- 0.5 mg IM once for a child aged less than five years.
NO REPEATS
admin of glucagon
- Dissolve the powder using the syringe within the kit and administer IM.
- The preferred site is the lateral thigh as this has the best absorption. If this site is not suitable use the lateral upper arm.
adverse affects of glucagon
nil
usual onset of glucagon
5-10 mins
usual duration of glucagon
15-60 mins
pharmokinetics of glucagon
- Glucagon is predominantly excreted unchanged into bile and urine.
- There are no significant effects from liver or kidney impairment on acute administration.
Glucagon relies on stored glycogen being available to exert its effect and if glycogen stores are not available, glucagon may be ineffective. Examples include if the patient:
ū Does not have diabetes.
ū Has sepsis.
ū Is a young child.
ū Has undergone strenuous exercise.
ū Has not eaten food for more than 12 hours.
ū Is suffering from adrenal insufficiency.
ū Is suffering from chronic hypoglycaemia.
ū Is suffering from alcohol-induced hypoglycaemia.
indication of glucose gel
Hypoglycaemia in adults and children provided the patient is conscious enough to be able to swallow safely.
Hypoglycaemia in neonates.
cautions and contraindications of glucose gel
nil
dosage of glucose gel
- 10-20 g for all ages.
- Administer one sachet and repeat every ten minutes if hypoglycaemia persists or recurs.
onset and duration of glucose gel
Usual onset of effect
* 5-10 minutes.
Usual duration of effect
* 30-60 minutes.
GTN mechanism
- GTN is a vasodilator. It acts on vascular smooth muscle to cause venous and arterial vasodilation, with the predominant effect being on veins.
- The mechanism of action is not clear, but it appears that GTN results in the formation of nitric oxide which is a vasodilator. GTN causes:
ū A reduction in venous return (preload) to the heart. This reduces ventricular filling and cardiac output which reduces myocardial oxygen demand.
ū Arterial dilation which reduces peripheral resistance (afterload). This reduces the force the left ventricle must overcome to eject blood into the arteries which reduces myocardial oxygen demand.
ū Dilation of the coronary arteries which may increase coronary blood supply, though this is not usually clinically significant.
indications of GTN
Myocardial ischaemia.
Cardiogenic pulmonary oedema.
Control of hypertension associated with autonomic dysreflexia.
Control of hypertension (usually in conjunction with labetalol or metoprolol) prior to fibrinolytic treatment for STEMI.
Control of hypertension (usually in conjunction with labetalol or metoprolol) during inter-hospital transfer for STEMI.
contraindications of GTN
Known severe allergy.
Systolic BP less than 100 mmHg.
Heart rate less than 40/minute.
Heart rate greater than 150/minute.
Ventricular tachycardia.
cautions of GTN
STEMI, especially RV (If there is low CO then GTN decreases this)
STEMI involving RV can cause significant reduction in RV contractility, this decreases CO
GTN can cause a significant fall in venous pressure which decreases CO
Frail patient
Signs of shock (CO may fall further with GTN)
Dysrhythmia (CO may fall further with GTN)
Phosphodiesterase in the last 24 hours (Severe/prolonged hypotension may occur) (EG phosphodiesterase inhibitors used to treat erectile dysfuntion and pulmonary hypertension)
Known aortic or mitral stenosis (Narrowing of aortic or mitral valves) - (CO may fall further with GTN) (Rheumatic fever can lead to this)
dosage of GTN
Myocardial ischaemia: 0.4 mg every 3-5 mins.
Increase dosing to 10 mins if any cautions
ACPO 0.8 mg every 3-5 mins
HTN 0.4-0.8 mg every 3-5 mins
IF ADMINED IN CAUTION: lie flat, IV acsess, interval 10 mins, fluids ready if needed
common adverse affects of GTN
- Hypotension.
- Flushing.
- Headache.
- Tachycardia.
- Feeling light-headed.
onset of GTN
1-2 mins
duration of GTN
15-30 mins
pharamacokineics of GTN
- GTN is rapidly absorbed from the oral mucosa and reaches the vascular system without passing through the liver.
- GTN is predominantly metabolised in the liver.
- There are no significant effects from liver impairment on acute administration.
common interactions of GTN
The effects may be increased if the patient is taking an antihypertensive medicine.
* Severe and/or prolonged hypotension may occur if a medicine for erectile dysfunction has been taken within the last 24 hours:
ū There is a range of medicines with different names used for erectile dysfunction and some of them (particularly sildenafil) are also used in the treatment of pulmonary hypertension.
ū All of these medicines are long-acting vasodilators and the administration of GTN may cause further vasodilation.
GTN and STEMI cautions
GTN must be used with caution in the presence of STEMI because the risks may outweigh the benefits:
ū GTN may cause a significant fall in cardiac output.
ū GTN has a role in treating symptomatic myocardial ischaemia, but does not
usually have a significant role in treating STEMI.
* Particular caution must be used in the presence of STEMI involving the right ventricle and personnel must have a low threshold for withholding GTN:
ū STEMI involving the right ventricle can result in a significant reduction in right ventricular contractility.
ū When the right ventricle is significantly impaired, it may provide little in the way of contribution to cardiac output and blood may be passively flowing down a pressure gradient between the inferior vena cava (IVC), the superior vena cava (SVC) and the left atrium.
ū This may result in the preload (filling) of the left side of the heart being dependent on the venous pressures within the IVC and SVC.
ū GTN can result in a significant fall in venous pressure (and thus a fall in preload) which may cause a significant fall in cardiac output.
ibuprofen mechnism
- Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that is predominantly used for treating pain.
- Ibuprofen inhibits the activity of the enzyme prostaglandin synthetase, reducing prostaglandin production and causing a reduction in inflammation, pain and fever.
ibuprofen indications
Mild pain (usually in combination with paracetamol), particularly soft tissue pain, musculoskeletal pain or headache.
May be administered in addition to other medicines for moderate to severe pain, particularly when the transport time is long. This is not a priority but will reduce the need for subsequent analgesia and improve the quality of pain relief.
ibuprofen contrindications
Known severe allergy
Pregnancy
Presence of sepsis, dehydration, shock or clinically significant bleeding (Ibuprofen can worsen renal impairment and increase bleeding risk)
Known worsening of bronchospasm with NSAIDS