Furosemide Oral Solution

For some patients, swallowing tablets can be difficult, making a liquid formulation a more practical option for long-term treatment. Furosemide oral solution is a prescription-only liquid loop diuretic containing the same active ingredient as furosemide tablets. It is used to treat oedema associated with heart failure, liver disease, and kidney disease, and to support blood pressure control in adults and children where a liquid formulation is clinically appropriate. This page provides factual information about furosemide oral solution to support an informed conversation with a prescriber. A prescription can only be issued following a clinical consultation.

Furosemide oral solution is a liquid prescription medicine containing furosemide as the active ingredient. It belongs to the loop diuretic class of medicines, which work by acting on the kidneys to increase the production of urine. Liquid furosemide is available as an alternative to furosemide tablets for patients who have difficulty swallowing solid oral dosage forms, for whom dose titration in smaller increments is required, or where a liquid formulation has been specifically recommended by their prescriber.

Furosemide oral solution is available in two strengths through this service: 20 mg per 5 ml and 40 mg per 5 ml. The licensed indications are the same as for furosemide tablets: oedema (fluid retention) associated with heart failure, liver cirrhosis, and kidney disease, and hypertension. The solution may also be used in children when prescribed by a specialist, though this service is for adult patients only.

Because furosemide oral solution contains the same active ingredient as furosemide tablets, the same monitoring requirements apply. Regular blood tests to check kidney function, potassium, sodium, and other electrolytes are an important part of safe treatment with this medicine.

Important: Furosemide oral solution requires ongoing clinical monitoring. Regular blood tests to check kidney function, electrolytes (particularly potassium and sodium), and fluid balance are an essential part of safe treatment. Your prescriber will determine the appropriate monitoring schedule for you. Online prescribing is only appropriate where an adequate clinical history is available and where regular monitoring is in place. Your prescriber will assess this as part of the consultation.

Furosemide oral solution delivers furosemide in liquid form. Once absorbed into the bloodstream, it works by the same mechanism as furosemide tablets.

Action on the Loop of Henle

Furosemide acts on a structure inside the kidney called the loop of Henle, where sodium, potassium, and chloride are normally reabsorbed from the kidney filtrate back into the body. Furosemide blocks the sodium-potassium-chloride co-transporter in the thick ascending limb of the loop of Henle. This prevents reabsorption of these electrolytes. Water follows the electrolytes out of the body in urine, resulting in a significant increase in urine production. This is why loop diuretics are sometimes called water tablets.

Effects on Fluid Retention and Blood Pressure

By increasing urine production, furosemide reduces the amount of excess fluid retained in the tissues and in the blood vessels. In patients with oedema, this relieves swelling, breathlessness, and discomfort. In patients with high blood pressure, the reduction in circulating fluid volume lowers the pressure within blood vessels, reducing the strain on the heart. This makes furosemide a key medicine in cardiovascular therapy for patients with heart failure, fluid retention, and certain forms of hypertension.

The oral solution reaches the bloodstream via absorption from the gastrointestinal tract. The bioavailability of furosemide oral solution is generally similar to that of furosemide tablets, though individual absorption can vary. Your prescriber will monitor your response to treatment and adjust the dose if necessary.

Always take furosemide oral solution exactly as your prescriber instructs. The information below summarises key points from the current UK SmPC. Read the Patient Information Leaflet supplied with your medicine before starting treatment.

• Measure each dose carefully using the oral syringe or measuring device provided with the medicine. Do not use a household teaspoon, as this does not give an accurate dose.
• Take furosemide oral solution once or twice daily as directed by your prescriber. If you take it once daily, take it in the morning. If twice daily, take the second dose no later than mid-afternoon. Taking the dose late in the day increases the likelihood of needing to pass urine during the night.
• Furosemide oral solution can be taken with or without food.
• You may take the solution diluted in a small amount of water or juice if preferred. Check with your prescriber that this is appropriate with your specific product.
• If you miss a dose, take it as soon as you remember on the same day. If you only remember the following day, skip the missed dose and continue with your normal schedule. Do not take two doses on the same day.
• Do not stop taking furosemide oral solution without speaking to your prescriber first. Stopping suddenly can cause fluid to accumulate rapidly, worsening breathlessness and swelling.
• Attend all blood test appointments arranged by your prescriber. Furosemide can affect potassium, sodium, and kidney function, and these require regular monitoring throughout treatment.
• Furosemide oral solution will cause you to pass urine more frequently, particularly in the first few hours after each dose. Plan your daily routine to accommodate this, especially when first starting treatment or following a dose increase.

Furosemide oral solution is available in two strengths. Your prescriber will select the appropriate strength and dose volume based on the condition being treated, your kidney function, and your response to treatment.

Furosemide Oral Solution 20 mg/5 ml

Each 5 ml of this solution contains 20 mg of furosemide. This strength allows flexible dosing in smaller increments and is particularly useful when a lower starting dose is clinically appropriate, for example in older adults, patients with mild kidney impairment, or patients initiating diuretic therapy who may be sensitive to fluid shifts. The prescriber can calculate an exact volume to deliver the intended dose.

Furosemide Oral Solution 40 mg/5 ml

Each 5 ml of this solution contains 40 mg of furosemide. This is a more concentrated formulation and is typically used when the prescribed dose requires a smaller volume of liquid. A dose of 40 mg, for example, is delivered in just 5 ml of this strength, compared to 10 ml of the 20 mg/5 ml strength. Both strengths contain the same active ingredient at equivalent doses.

For most adults with oedema related to heart failure, the standard starting dose of furosemide is 40 mg once daily. For hypertension, lower doses are often used. Doses may be adjusted by your prescriber over time based on your clinical response. All dosing decisions are made by your prescriber. Do not adjust your dose or the volume you take without medical advice.

Furosemide oral solution contains the same active ingredient as furosemide tablets, and the side effect profile is the same. The information below is based on the current UK SmPC. Refer to the Patient Information Leaflet for the full list of side effects.

Common Side Effects (may affect up to 1 in 10 people)

• Increased frequency of passing urine, particularly in the first few hours after each dose. This is the intended therapeutic effect of the medicine.
• Dizziness or lightheadedness, particularly on standing up quickly. This may be more noticeable at the start of treatment or after a dose increase.
• Low potassium levels in the blood (hypokalaemia), which can cause muscle cramps, weakness, or heart palpitations. Regular blood tests are required to monitor this.
• Low sodium levels (hyponatraemia) and low magnesium, which may cause symptoms including fatigue, confusion, and muscle weakness
• Thirst and dry mouth due to fluid loss
• Raised blood uric acid levels, which may trigger or worsen gout in susceptible patients

Uncommon Side Effects (may affect up to 1 in 100 people)

• Nausea, vomiting, or diarrhoea
• Raised blood glucose levels, which may be relevant for patients with or at risk of diabetes
• Skin rash or itching

Serious Side Effects: Seek Urgent Medical Attention

Contact your prescriber or go to your nearest accident and emergency department promptly if you experience any of the following:

• Signs of severe electrolyte disturbance such as muscle weakness, significant cramps, confusion, or an irregular heartbeat
• A marked reduction in urine output, which may indicate a worsening of kidney function
• Signs of severe dehydration including extreme thirst, very dark urine, dizziness, and confusion
• Signs of a serious allergic reaction such as sudden swelling of the face, lips, tongue, or throat, difficulty breathing, or a severe skin reaction
• Hearing problems or ringing in the ears. Although more commonly associated with high-dose intravenous furosemide, any hearing changes during oral treatment should be reported to your prescriber promptly.

Report any suspected side effect to your prescriber, pharmacist, or via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Furosemide Oral Solution May Be Suitable If You:

• Are an adult with a confirmed diagnosis of oedema associated with heart failure, liver cirrhosis, or kidney disease
• Have hypertension and have been assessed as requiring diuretic therapy
• Have difficulty swallowing tablets and have been recommended a liquid formulation by your prescriber or pharmacist
• Are already prescribed furosemide oral solution and require a repeat prescription through an online prescribing service, with recent monitoring results available

Furosemide Oral Solution Is Not Suitable If You:

• Are anuric (producing no urine) or have severe kidney failure where diuretic therapy is contraindicated
• Have severely low potassium or sodium levels that have not yet been corrected
• Have severe liver disease with hepatic coma or pre-coma
• Have Addison's disease (adrenal insufficiency)
• Are dehydrated or have a significant reduction in circulating blood volume
• Are pregnant, unless specifically assessed and recommended by a prescriber
• Are breastfeeding, as furosemide passes into breast milk
• Have a known allergy or hypersensitivity to furosemide, sulfonamides, or any excipient listed in the SmPC for this specific oral solution product
• Are under 18 years of age (this online service is for adults only)

The drug interactions for furosemide oral solution are the same as for furosemide tablets. Tell your prescriber about all medicines you take. Key interactions include:

• ACE inhibitors and angiotensin receptor blockers (ARBs): combining these with furosemide can cause a significant fall in blood pressure, particularly with the first dose.
• NSAIDs such as ibuprofen: these can reduce the diuretic effect of furosemide and increase the risk of kidney problems. Avoid regular use of NSAIDs during treatment.
• Digoxin: low potassium caused by furosemide increases the risk of digoxin toxicity. Electrolyte monitoring is especially important in patients taking both medicines.
• Lithium: furosemide can increase lithium levels, raising the risk of toxicity. Close monitoring is required.
• Aminoglycoside antibiotics such as gentamicin: combined use may increase the risk of hearing damage and kidney toxicity.
• Other antihypertensive medicines: the blood pressure-lowering effect of furosemide may be enhanced when taken alongside other medicines in this class.

Your prescriber will review all of your current medicines during the clinical assessment before any prescription is considered.

Furosemide oral solution is a Prescription Only Medicine that requires ongoing clinical monitoring. The clinical consultation is the essential first step. A prescription will only be issued if a registered prescriber concludes, based on their individual assessment of your clinical circumstances, that this medicine is appropriate for you.

When you complete a consultation through Pharmacy Planet, a registered prescriber will review the information you provide. This includes your diagnosis, fluid balance status, kidney function, electrolyte results, current medicines, and whether a liquid formulation is appropriate for your needs. Because furosemide requires regular monitoring, the prescriber will also assess whether adequate monitoring is in place before considering whether to issue a prescription.

If you are under the care of your GP, cardiologist, or nephrology team for the condition being treated with furosemide, please keep them informed of all medicines prescribed through online services. Coordinated care ensures the safest outcome, particularly for a medicine that requires regular monitoring.

• Store below 25°C.
• Keep the bottle tightly closed after use to prevent contamination and evaporation.
• Protect from light. Store in the original packaging.
• Keep out of the sight and reach of children.
• Do not use after the expiry date printed on the label. Once opened, use within the period stated by the manufacturer on the packaging or Patient Information Leaflet.
• Do not dispose of medicines via household waste or wastewater. Return unused or out-of-date medicine to your pharmacist for safe disposal.
• Always keep the oral syringe or measuring device that came with the medicine. Wash it after each use and store it with the bottle.
• Full storage and handling instructions are provided in the Patient Information Leaflet supplied with your medicine. Different manufacturers may have specific storage instructions for their product. Always check the leaflet that comes with your specific supply.

The table below compares liquid oral solution products available at Pharmacy Planet. These formulations provide the same active ingredients as standard tablets or capsules in a liquid form, suitable for patients who have difficulty swallowing solid oral medicines.

Important: This comparison is for general information only and does not replace medical advice. A prescriber will decide which treatment is suitable for you following an online consultation.

Pharmacy Planet is a GPhC-registered online pharmacy. We provide access to prescription medicines through a structured, clinically led consultation process. All prescriptions are reviewed and dispensed by qualified, registered healthcare professionals.

For medicines such as furosemide that require ongoing monitoring, our prescribers take particular care to ensure that appropriate clinical oversight is in place. We follow GPhC standards, and MHRA guidance across all aspects of our service.

Our pharmacy team is available to answer questions about furosemide oral solution, liquid antihypertensive medicines, or any aspect of your cardiovascular therapy or diuretic treatment. We are committed to clear, accurate, and patient-centred information that supports your health with confidence.

References

1. Electronic Medicines Compendium (eMC). Furosemide Oral Solution — Summary of Product Characteristics. https://www.medicines.org.uk/emc. Accessed May 2026.
2. National Institute for Health and Care Excellence (NICE). Chronic heart failure in adults: diagnosis and management. NICE guideline NG106. https://www.nice.org.uk/guidance/ng106. Accessed May 2026.
3. NHS. Furosemide. https://www.nhs.uk/medicines/furosemide. Accessed May 2026.
4. Joint Formulary Committee. British National Formulary (BNF). Furosemide. BMJ Group and Pharmaceutical Press. https://bnf.nice.org.uk. Accessed May 2026.
5. Medicines and Healthcare products Regulatory Agency (MHRA). Yellow Card — report a side effect. https://yellowcard.mhra.gov.uk. Accessed May 2026.