FUROSEMIDE
presentation - what the drug is sealed in, its concentration and how it might look
Furosemide can come in many presentations, however most NHS Ambulance Services prefer the following:
5ml ampoule containing 10mg/1ml furosemide for injection
NB: Furosemide has been removed from JRCALC due to a national shortage, it is not known when this will be amended again.
INDICATIONS - reasons you should administer this drug
Furosemide in it’s many different presentations can be used to treat a wide range of fluid retentive illnesses including oedema and hypertension, however UK Ambulance Services tend to only use IV Furosemide for the treatment of:
Acute pulmonary oedema.
Congested Hear Failure (CHF).
CONTRAINDICATIONS - reasons you should not administer this drug
Known hypersensitivity or allergy to furosemide or other sulfonamide-type loop diuretics.
Severe hypovolaemia or dehydration.
Anuria (no urine output) or severe renal failure with no response to previous loop diuretics and suspected complete obstruction.
Severe hypotension (local cut-offs usually SBP < 90 mmHg, but check your guideline).
Hepatic coma or pre-coma (risk of precipitating/worsening encephalopathy).
Significant hypokalaemia or hyponatraemia that is known and untreated.
Pregnancy – usually avoided unless clear benefit outweighs risk and directed by a doctor.
cautions - reasons that if you administer this drug you must monitor for side effects more than usual
Borderline / mild hypotension.
Renal impairment (CKD, AKI) – risk of further kidney injury and large electrolyte shifts.
Hepatic cirrhosis / liver disease (risk of encephalopathy; often requires very careful titration in hospital).
Elderly or frail patients – prone to dehydration, postural hypotension, AKI and electrolyte imbalance.
Diabetes mellitus – risk of hyperglycaemia and masking of worsening renal function.
Gout or hyperuricaemia – furosemide increases uric acid levels.
Pre-existing electrolyte disturbances (especially low K⁺, Na⁺, Mg²⁺, Ca²⁺).
Concomitant ototoxic drugs (e.g. high-dose aminoglycosides): IV furosemide at high doses/rapid injection can add to ototoxicity.
Concomitant antihypertensives / vasodilators / nitrates – additive hypotensive effect.
Known allergy to sulfonamides – cross-sensitivity is uncommon but often listed as a caution
pharmacological action - what does it to the body and what does the body do to it?
FREC 3 and FREC 4:
Furosemide is a strong diuretic, meaning it helps the body get rid of extra fluid. It works in the kidneys by blocking the reabsorption of salt and water, so more of it is passed out as urine. This reduces the amount of fluid in the blood, which helps lower the pressure in the lungs and makes breathing easier in conditions like pulmonary oedema.
FREUC 5 and L4 AAP
Pharmacokinetics:
Absorption: Intravenous. ~5 minutes; peak ~30 minutes; duration 2–3 hours.
Distribution: Highly protein-bound (~95%); low volume of distribution.
Metabolism: Minimal hepatic metabolism.
Elimination: Mainly renal excretion (unchanged); half-life ~1–2 hours (longer in renal impairment).
Pharmacodynamics
Class: Loop diuretic.
Mechanism: Blocks the Na⁺-K⁺-2Cl⁻ co-transporter in the thick ascending limb of the loop of Henle which stops reabsorption of sodium, chloride and potassium.
Effects:
Potent diuresis with increased excretion of water, Na⁺, K⁺, Cl⁻.
Venodilation → reduced preload → improved pulmonary congestion.
Risk of hypotension, electrolyte loss (K⁺, Na⁺, Mg²⁺, Ca²⁺) and AKI if over-diuresed.
side effects - unwanted secondary effects of this drug
Increased urination.
Thirst or dehydration.
Dizziness or light-headedness.
Headache.
Nausea.
Low blood pressure.
Muscle cramps or weakness (from low potassium).
Fatigue.
Raised blood sugar.
Raised uric acid (can trigger gout).
Tinnitus (ringing in the ears).
dosage and administration - how much do we give and how do we give it?
Adults:
Route: Intravenous
Initial dose: 40mg
Repeat dose: NA
Dose Interval: NA
Concentration: 10mg/1ml
Volume: 4ml
Max dose: 40mg
legislation and regulations - what legal class of drug is it, who can possess it and who can give it?
Furosemide is a Prescription-Only Medicine (POM). It is not a Controlled Drug. It is listed in Schedule 17 of the Human Medicines Regulations 2012, which authorises certain healthcare professionals, including paramedics, to administer specific POMs without a prescription. Therefore:
It is a Prescription-Only Medicine (POM):
POMs would normally require a prescription from an authorised prescriber such as a medical doctor or Advanced Paramedic.
It is listed in Schedule 17 of the Human Medicines Regulations 2012:
Paramedics may possess and administer furosemide in the course of their duties without needing an individual prescription.
NB: Administration must still follow local clinical guidelines, governance processes and organisational policy.