Furosemide

What Does Furosemide Do?

Furosemide, a loop diuretic, is primarily used to manage and reduce fluid retention linked with heart failure, kidney disease, and liver cirrhosis. It is also used for addressing high blood pressure, acute pulmonary oedema, and cerebral oedema.

How Does Furosemide Work? (the complicated stuff)

Furosemide inhibits the sodium-potassium-chloride cotransporter in the kidney's ascending loop of Henle. This obstruction results in a reduction in the reabsorption of sodium, chloride, and potassium ions, thus increasing their excretion via urine. Consequently, the diuresis prompts diminishes fluid volume, thereby reducing blood pressure.

Drug Type and Category of Furosemide

Furosemide is classified as a loop diuretic medication. 

What dosage of Furosemide should you be taking?

NICE Dosing Guidelines¹

• Adults: The initial dose typically ranges from 20 to 50 mg, which can be administered via intramuscular or intravenous injection. The dose may be increased by 20 mg every 2 hours until the desired effect is achieved.
• Children: For neonates, the dosing is generally 0.5–1 mg/kg every 12–24 hours, depending on gestational age. For children aged 1 month to 11 years, the recommended dose is also 0.5–1 mg/kg.

Monitoring Requirements

Monitoring is crucial for patients on furosemide, especially for those at high risk, such as the elderly or those with chronic kidney disease. 

Key monitoring parameters include:

• Baseline assessments: Blood pressure, electrolytes, and serum creatinine levels should be checked before starting treatment.
• Follow-up: After initiating or adjusting the dose, these parameters should be reassessed after 1-2 weeks. For high-risk patients, monitoring may need to occur sooner, within 5-7 days.

Abnormal Results Management

If serum creatinine increases by more than 20%, renal function should be re-evaluated within 2 weeks. More significant increases (30-50% or >200 µmol/L) may require immediate clinical review and potential dose adjustment or cessation of furosemide.

Potassium levels must also be monitored, with specific actions required if levels drop below critical thresholds.

What are the side-effects of Furosemide?

Common Side Effects

• Gastrointestinal Issues: Diarrhoea, constipation, and loss of appetite.
• Neurological Symptoms: Headache, dizziness, and blurred vision.
• Sensory Changes: Numbness or tingling in extremities.

Serious Side Effects

It's crucial to seek immediate medical attention if any of the following serious side effects occur:

• Allergic Reactions: Symptoms may include hives, difficulty breathing, and swelling of the face or throat.
• Electrolyte Imbalance: Signs include increased thirst, muscle weakness, cramps, and changes in heart rhythm due to low potassium (hypokalemia) or other electrolytes.
• Kidney Issues: Symptoms include decreased urination, swelling, and feeling unusually tired.
• Hearing Problems: Ringing in the ears (tinnitus) or hearing loss, which can be temporary or permanent.
• Pancreatitis: Severe abdominal pain, nausea, vomiting, and fever.
• Liver Damage: Symptoms such as jaundice (yellowing of the skin or eyes) and dark urine.
• Severe Skin Reactions: Blistering or peeling skin, fever, and sore throat.
• Orthostatic Hypotension: Light-headedness or fainting upon standing up due to low blood pressure.

Furosemide can also lead to dehydration, which may exacerbate other conditions and lead to serious complications. Patients are advised to stay hydrated and monitor for any significant changes in their health status while on this medication.

Drug Interactions

Antibiotics

Furosemide may interact with certain antibiotics like amikacin, increasing the risk of ototoxicity (ear toxicity). Avoid combining these medications or use an alternate drug.

NSAIDs

Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen can increase furosemide levels by competing for plasma protein binding. Monitor closely and adjust furosemide dose as needed.

Lithium

Furosemide can increase lithium levels, potentially leading to lithium toxicity. Monitor lithium levels closely when starting, stopping or changing furosemide doses.

Cyclosporine

Combining furosemide with cyclosporine may increase the risk of nephrotoxicity (kidney damage). Monitor kidney function closely if using these medications together.

Ethacrynic Acid

Furosemide and ethacrynic acid are both loop diuretics. Using them together may increase the risk of adverse effects and should be avoided if possible.

In general, it's important to inform your healthcare provider about all medications you are taking, including over-the-counter drugs and supplements, to avoid potentially harmful interactions with furosemide. Periodic monitoring of electrolytes and kidney function is also recommended for patients on this medication.

Natural Alternatives to Furosemide

Lowering your risk of heart disease is the key thing. That’s achieved through years of healthy living, exercise, good diet, and reducing stress levels.

There are several natural alternatives to furosemide, a commonly prescribed diuretic, that may help with fluid retention. These alternatives include various herbs and dietary supplements known for their potential diuretic effects.

Natural Diuretics

1. Dandelion: Often used in herbal medicine, dandelion is thought to promote urine production. Some studies suggest that dandelion extract may increase urine output, although more research is needed to confirm its effectiveness in humans. ^2,4
2. Parsley: This common culinary herb has been traditionally used as a diuretic. While animal studies indicate it may enhance urine flow, human studies are lacking, leaving its effectiveness uncertain. ^3,5
3. Hibiscus: Known for its vibrant flowers, hibiscus can be consumed as a tea and is suggested to have mild diuretic properties. However, studies have shown mixed results regarding its efficacy in humans. ^3,4
4. Ginger: This commonly used spice may also have diuretic effects, although concrete evidence from human studies is limited. ^2,3
5. Nigella Sativa (Black Seed): This herb has been studied for its diuretic effects and may help increase urine output. It is commonly used in Middle Eastern cuisine. ³
6. Horsetail: Traditionally used as a diuretic, horsetail has shown some promise in small studies, but more research is needed to establish its effectiveness and safety. ^4,5
7. Green and Black Tea: Both types of tea contain caffeine, which has mild diuretic effects. Regular consumption may help with fluid retention, although tolerance can develop over time. ^4,5
8. Other Options: Foods like coffee, certain berries, and even alcohol in moderation are known to have diuretic effects. However, their long-term use and health implications should be considered carefully. ^3,5

Interesting facts about Furosemide

The effects of furosemide are relatively short-lived, lasting about 4-6 hours. This necessitates multiple doses per day for ongoing conditions, such as chronic heart failure.

Disclaimer

This article is generated for informational purposes only. It was created in December 2024. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References:

1. https://bnf.nice.org.uk/drugs/furosemide/
2. https://www.mayoclinic.org/healthy-lifestyle/weight-loss/expert-answers/water-retention/faq-20058063
3. https://www.medicalnewstoday.com/articles/313001
4. https://www.healthline.com/nutrition/best-diuretic-foods-drinks
5. https://health.clevelandclinic.org/natural-diuretics