Sparkal (Amiloride / Hydrochlorothiazide)
Potassium-sparing diuretic combination for high blood pressure and edema
Sparkal is a prescription combination diuretic containing amiloride hydrochloride and hydrochlorothiazide. It is prescribed for the treatment of high blood pressure (hypertension), edema caused by heart failure, and fluid accumulation in the abdomen due to liver cirrhosis. The unique advantage of Sparkal is that amiloride helps preserve potassium and magnesium, counteracting the electrolyte losses commonly caused by hydrochlorothiazide alone. This guide covers uses, dosage, side effects, drug interactions, and safety information based on current international medical guidelines.
Quick Facts
Key Takeaways
- Sparkal combines two diuretics: amiloride (potassium-sparing) and hydrochlorothiazide (thiazide), providing effective blood pressure control while minimizing potassium loss.
- Available in two strengths — Sparkal (5 mg/50 mg) for edema, and Sparkal Mite (2.5 mg/25 mg) commonly used for hypertension.
- Regular blood tests are essential to monitor potassium, sodium, and kidney function during treatment.
- Do not take with other potassium-sparing diuretics, potassium supplements, or in patients with severe kidney impairment or hyperkalemia.
- Not recommended during pregnancy (especially the last 6 months) or breastfeeding. Consult your doctor for safer alternatives.
What Is Sparkal and What Is It Used For?
Sparkal belongs to a class of medications known as potassium-sparing diuretic combinations. It contains two active ingredients that work synergistically to promote diuresis (increased urine production) and lower blood pressure. Hydrochlorothiazide, a thiazide diuretic, works in the distal convoluted tubule of the kidney by inhibiting sodium reabsorption, which leads to increased excretion of sodium and water. Amiloride hydrochloride works in the collecting duct by blocking epithelial sodium channels (ENaC), providing additional diuretic effect while crucially reducing the loss of potassium and magnesium that typically accompanies thiazide therapy.
This combination is particularly valuable because one of the most common adverse effects of thiazide diuretics used alone is hypokalemia (low potassium). By pairing hydrochlorothiazide with amiloride, the medication provides the antihypertensive and diuretic benefits of a thiazide while maintaining more stable electrolyte levels. According to guidelines from the European Society of Cardiology (ESC) and the National Institute for Health and Care Excellence (NICE), thiazide-type diuretics remain one of the first-line treatment options for essential hypertension, and potassium-sparing combinations are preferred for patients at risk of hypokalemia.
Sparkal is prescribed for three primary indications:
- Hypertension (high blood pressure): Reducing blood pressure lowers the risk of stroke, myocardial infarction, and chronic kidney disease. The typical dose for hypertension is one Sparkal Mite (2.5 mg/25 mg) tablet daily.
- Edema due to heart failure: When the heart cannot pump blood efficiently, fluid accumulates in the lungs, legs, and abdomen. Sparkal helps remove this excess fluid while preserving potassium, which is critical for proper cardiac function.
- Ascites from liver cirrhosis: Advanced liver disease often leads to fluid accumulation in the peritoneal cavity. Sparkal promotes sodium and water excretion to manage this condition.
The active ingredients in Sparkal — amiloride hydrochloride and hydrochlorothiazide — are also available in other branded and generic formulations worldwide. Physicians may choose this specific combination when monotherapy with either agent alone has proven insufficient or when potassium preservation is a clinical priority. For many patients, the fixed-dose combination simplifies treatment by reducing the number of separate tablets required each day, which can improve medication adherence.
What Should You Know Before Taking Sparkal?
Before starting treatment with Sparkal, your doctor will evaluate your overall health, kidney function, and electrolyte balance. It is essential that you inform your healthcare provider about all existing medical conditions, medications, and supplements you are taking. The following sections detail the key contraindications, warnings, and precautions associated with Sparkal use.
Contraindications
You must not take Sparkal or Sparkal Mite if any of the following apply to you:
- Allergy to amiloride hydrochloride, hydrochlorothiazide, or any other ingredient in the tablets (see Contents section).
- Hypersensitivity to sulfonamide-derived substances, as hydrochlorothiazide is chemically related to sulfonamides.
- Severe kidney impairment or anuria (absence of urine production) — the medication relies on adequate renal function to work.
- Severe liver impairment — electrolyte disturbances may worsen hepatic encephalopathy.
- Hyperkalemia (elevated blood potassium) — amiloride further raises potassium, which can be life-threatening.
- Concurrent use of other potassium-sparing diuretics (e.g., spironolactone, triamterene, eplerenone) or potassium supplements.
- Gout — hydrochlorothiazide can increase uric acid levels and trigger gout attacks.
Warnings and Precautions
Talk to your doctor or pharmacist before taking Sparkal if you have any of the following conditions:
- Mild to moderate kidney impairment: Dose adjustments may be required and more frequent blood monitoring is necessary.
- Mild to moderate liver disease: Electrolyte imbalances can worsen liver function; close monitoring is essential.
- Elderly patients: Older adults are more susceptible to electrolyte disturbances, dehydration, and orthostatic hypotension (dizziness upon standing). Lower starting doses and careful monitoring are recommended.
- Diabetes mellitus: Hydrochlorothiazide can raise blood glucose levels, potentially worsening diabetic control. Your diabetes medication doses may need adjustment.
- Elevated uric acid, cholesterol, or triglycerides: Hydrochlorothiazide may increase levels of these substances in the blood.
- Systemic lupus erythematosus (SLE): Hydrochlorothiazide can activate or worsen lupus.
- History of skin cancer: Long-term use of hydrochlorothiazide, particularly at high doses, has been associated with an increased risk of non-melanoma skin cancer (basal cell carcinoma and squamous cell carcinoma). Protect your skin from sun exposure and UV radiation while taking Sparkal, and report any new or changing skin lesions to your doctor.
- Respiratory problems: Rarely, hydrochlorothiazide has been associated with acute pulmonary edema or acute respiratory distress syndrome (ARDS). Seek immediate medical attention if you experience severe breathlessness after taking Sparkal.
- Eye problems: Hydrochlorothiazide may cause choroidal effusion (fluid accumulation in the eye) or acute angle-closure glaucoma within hours to weeks of starting treatment. If you experience decreased vision or eye pain, contact your doctor immediately. Patients with a history of penicillin or sulfonamide allergy may have a higher risk.
Because amiloride is potassium-sparing, Sparkal carries a risk of hyperkalemia (dangerously high potassium levels). Signs include muscle weakness, fatigue, confusion, speech difficulties, and irregular heartbeat. Your doctor will check your blood potassium levels before starting treatment and regularly during therapy, especially if you have diabetes, kidney impairment, or are elderly.
Pregnancy and Breastfeeding
If you are pregnant, think you may be pregnant, plan to become pregnant, or are breastfeeding, talk to your doctor before using Sparkal.
Pregnancy: Sparkal is not recommended during pregnancy. Your doctor will usually prescribe an alternative medication. Hydrochlorothiazide crosses the placenta and can cause harm to the fetus, particularly if used during the last six months of pregnancy. Potential risks include electrolyte imbalances, reduced placental blood flow, and neonatal jaundice or thrombocytopenia. According to the European Medicines Agency (EMA) and the British National Formulary (BNF), thiazide diuretics should be avoided in pregnancy unless absolutely essential.
Breastfeeding: Sparkal is not recommended while breastfeeding. Hydrochlorothiazide is excreted in breast milk and may reduce milk production. Amiloride excretion into breast milk has not been adequately studied. If you need to take a diuretic while breastfeeding, your doctor will advise on a safer alternative.
Driving and Operating Machinery
Sparkal can cause side effects such as dizziness, fatigue, and weakness, particularly at the start of treatment or when doses are adjusted. If you experience these symptoms, do not drive or operate machinery until you know how Sparkal affects you. The risk of dizziness increases when standing up quickly (orthostatic hypotension), especially in warm weather or after exercise.
Food, Drink, and Alcohol
Your doctor may advise you to modify your diet while taking Sparkal. Because amiloride preserves potassium, you should avoid foods very high in potassium (such as bananas, oranges, potatoes, tomatoes, and salt substitutes containing potassium chloride) unless your doctor says otherwise. Alcohol can intensify the blood-pressure-lowering effect of Sparkal, potentially causing dizziness when standing up quickly. Minimize alcohol consumption during treatment.
Important Information About Excipients
Sparkal tablets contain lactose monohydrate and wheat starch as inactive ingredients. If you have been told by your doctor that you have an intolerance to certain sugars, consult your doctor before taking this medicine. The wheat starch content results in only trace amounts of gluten: a Sparkal tablet contains no more than 8.3 micrograms of gluten, and a Sparkal Mite tablet no more than 4.2 micrograms. This is very unlikely to cause problems if you have celiac disease (gluten intolerance). However, if you have a wheat allergy (which is different from celiac disease), you should not take this medication.
How Does Sparkal Interact with Other Drugs?
Drug interactions can reduce the effectiveness of your medications or increase the risk of serious side effects. Sparkal interacts with a number of commonly prescribed drugs due to its effects on electrolyte balance, kidney function, and blood pressure. The following table summarizes the most important drug interactions. Always inform your healthcare provider about all medications you use, including over-the-counter drugs, vitamins, and herbal supplements.
Major Interactions
| Medication | Interaction Effect | Clinical Advice |
|---|---|---|
| Potassium supplements or potassium-sparing diuretics (spironolactone, triamterene, eplerenone) | Severe hyperkalemia risk — can cause cardiac arrhythmia and cardiac arrest | Contraindicated. Do not use together. |
| ACE inhibitors (enalapril, ramipril, lisinopril) | Increased risk of hyperkalemia and excessive blood pressure reduction | If combination is necessary, monitor potassium and renal function closely. |
| Lithium | Reduced lithium clearance leading to lithium toxicity (tremor, confusion, seizures) | Avoid combination. If essential, monitor lithium levels frequently. |
| Digitalis glycosides (digoxin) | Electrolyte disturbances (hypokalemia, hypomagnesemia) increase risk of digitalis toxicity | Monitor electrolytes and digoxin levels regularly. |
| Sotalol | Electrolyte imbalances may increase risk of QT prolongation and arrhythmias | Monitor ECG and electrolytes during concomitant use. |
Other Notable Interactions
| Medication | Interaction Effect | Clinical Advice |
|---|---|---|
| NSAIDs (ibuprofen, naproxen, diclofenac) | May reduce the diuretic and antihypertensive effects of Sparkal; increased risk of kidney impairment | Use with caution. Monitor blood pressure and kidney function. |
| Insulin and oral antidiabetics | Hydrochlorothiazide can raise blood glucose, reducing the effectiveness of diabetes medications | Monitor blood glucose more frequently. Dose adjustment may be needed. |
| Cholestyramine and colestipol | Reduced absorption of hydrochlorothiazide from the gut | Take Sparkal at least 1 hour before or 4 hours after these agents. |
| Corticosteroids and ACTH | Increased risk of hypokalemia (potassium depletion) despite amiloride component | Monitor electrolytes, especially potassium. |
| Barbiturates and sedatives | Enhanced orthostatic hypotension (dizziness on standing) | Rise slowly from sitting or lying positions. Report persistent dizziness. |
| Epinephrine (adrenaline) | Possible decreased response to epinephrine injections used for allergic reactions | Inform healthcare professionals treating allergic reactions that you take Sparkal. |
This list is not exhaustive. Many other medications can interact with Sparkal. Always consult your doctor or pharmacist before starting, stopping, or changing any medication. Bring a complete list of your current medications to every medical appointment.
What Is the Correct Dosage of Sparkal?
Always take Sparkal exactly as your doctor or pharmacist has instructed. Do not change the dose or stop taking the medication without consulting your doctor. The correct dosage depends on your medical condition, kidney function, and response to treatment. Your doctor will determine the most appropriate dose for you.
Adults
| Indication | Starting Dose | Maintenance Dose | Notes |
|---|---|---|---|
| Hypertension | 1 Sparkal Mite tablet daily (2.5 mg/25 mg) | 1 Sparkal Mite daily | May be combined with other antihypertensives as directed |
| Edema (heart failure) | 1 Sparkal tablet daily (5 mg/50 mg) | Adjusted by physician based on response | Equivalent to 2 Sparkal Mite tablets |
| Ascites (liver cirrhosis) | 1 Sparkal tablet daily (5 mg/50 mg) | Adjusted by physician based on response | Close monitoring of liver function and electrolytes required |
Sparkal is usually taken once daily in the morning, with or after food. Taking it in the morning helps ensure that the increased urine production does not interfere with sleep. Swallow the tablet whole with a glass of water. For patients who have difficulty swallowing, consult your pharmacist about alternative options.
Elderly Patients
Elderly patients may be more sensitive to the effects of Sparkal, particularly regarding electrolyte disturbances, dehydration, and orthostatic hypotension. Treatment is typically started at the lowest effective dose (1 Sparkal Mite tablet daily), with careful monitoring of kidney function, electrolytes (especially potassium and sodium), and blood pressure. Dose adjustments are made gradually based on clinical response and laboratory findings.
Children
Sparkal is not generally recommended for use in children. The safety and efficacy of amiloride/hydrochlorothiazide combination in pediatric patients have not been adequately established. If a doctor prescribes this medication for a child in exceptional circumstances, they will determine the appropriate dose based on the child's weight and clinical condition.
Missed Dose
If you forget to take your tablet, do not take a double dose to make up for the missed one. Simply take your next dose at the usual time and continue with your normal schedule. If you frequently forget doses, consider setting a daily alarm or using a pill organizer. Consistent daily use is important for optimal blood pressure control.
Overdose
If you have taken too much Sparkal, or if a child has accidentally swallowed any tablets, contact your doctor, go to the nearest emergency room, or call your local poison control center immediately. Symptoms of overdose may include severe dehydration, dangerously low blood pressure, confusion, muscle weakness, irregular heartbeat, and electrolyte imbalances (particularly hyperkalemia from amiloride and hyponatremia from hydrochlorothiazide). Immediate medical treatment is essential.
Stopping Treatment
Do not stop taking Sparkal without consulting your doctor, even if you feel well. Hypertension is often asymptomatic, and stopping medication abruptly can cause a rebound increase in blood pressure, which raises the risk of cardiovascular events such as stroke or heart attack. If your doctor decides to discontinue Sparkal, they may reduce your dose gradually or switch you to an alternative medication.
What Are the Side Effects of Sparkal?
Like all medicines, Sparkal can cause side effects, although not everybody gets them. Most side effects are mild and may improve as your body adjusts to the medication. However, some side effects require immediate medical attention. The following frequency grid is based on standardized medical reporting conventions used by the European Medicines Agency (EMA).
Contact your doctor or go to the emergency room immediately if you experience: signs of severe allergic reaction (fever, rash, swelling, difficulty breathing, drop in blood pressure), severe shortness of breath or lung problems, signs of infection with high fever and severely worsened general condition, or sudden vision changes or eye pain.
Common
May affect up to 1 in 10 people
- Weakness and fatigue
- Loss of appetite
- Dizziness and headache
- Heart rhythm disturbances
- Nausea, diarrhea, and abdominal pain
- Skin rash (exanthema) and itching
- Shortness of breath
- Elevated blood sugar levels
- Increased uric acid in the blood
- Pain in arms and legs
Uncommon
May affect up to 1 in 100 people
- Joint pain, chest and back pain
- Erectile dysfunction (impotence)
- Orthostatic hypotension (dizziness upon standing)
- Palpitations and chest pain
- Tingling sensations (“pins and needles”)
- Gastrointestinal disturbances: bad taste, vomiting, bloating, constipation, gas, hiccups
- Thirst, stomach pain, nasal congestion, gout
- Low sodium (hyponatremia) causing nausea, malaise, muscle weakness, and confusion
- Dehydration causing general weakness, dizziness, and fainting
- Muscle cramps, sleep disturbances, nervousness, depression, confusion
- Urinary problems and visual disturbances
Rare
May affect up to 1 in 1,000 people
- Hypersensitivity reactions with fever, rash, swelling, and blood pressure drop
- Blood disorders: decreased white blood cells (agranulocytosis), anemia
- Reduced consciousness and fainting
- Gastrointestinal bleeding
- Flushing and photosensitivity (increased sun sensitivity)
- Vasculitis (inflammation of blood vessel walls)
- Jaundice (cholestasis) and cough
- Impaired kidney function
- Hyperkalemia causing muscle weakness, confusion, and speech difficulties
Very Rare
May affect up to 1 in 10,000 people
- Acute respiratory distress syndrome (ARDS) — severe breathlessness, fever, weakness, and confusion
Frequency Not Known
Cannot be estimated from available data
- Non-melanoma skin cancer (basal cell carcinoma, squamous cell carcinoma) of the skin and lips
- Decreased vision or eye pain due to increased eye pressure (possible signs of choroidal effusion or acute angle-closure glaucoma)
If you experience any side effects, including those not listed above, talk to your doctor or pharmacist. You can also report side effects directly to your national medicines regulatory agency. By reporting side effects, you help provide more information on the safety of this medicine.
It is important to note that the benefit of treating your condition with Sparkal generally outweighs the risk of side effects for most patients. Many of the common side effects (fatigue, mild dizziness) are transient and resolve within the first few weeks of treatment. Your doctor has prescribed this medication because they judge that the benefits outweigh the risks for your specific situation. If side effects persist or become bothersome, do not stop taking the medication on your own — speak to your doctor about adjusting the dose or switching to an alternative.
How Should You Store Sparkal?
Proper storage is essential to maintain the effectiveness and safety of your medication. Follow these guidelines:
- Keep out of the sight and reach of children. Store in a secure location.
- Do not use after the expiry date printed on the carton after “EXP.” The expiry date refers to the last day of that month.
- Store at room temperature (below 25°C / 77°F) in the original container to protect from moisture.
- Do not dispose of medicines via wastewater or household waste. Ask your pharmacist how to properly dispose of medicines that are no longer needed. These measures help protect the environment.
If you notice any changes in the appearance of your tablets (discoloration, crumbling, or unusual odor), do not take them and consult your pharmacist for a replacement.
What Does Sparkal Contain?
Active Ingredients
- Sparkal: Amiloride hydrochloride 5 mg + Hydrochlorothiazide 50 mg per tablet
- Sparkal Mite: Amiloride hydrochloride 2.5 mg + Hydrochlorothiazide 25 mg per tablet
Inactive Ingredients (Excipients)
Lactose monohydrate, magnesium stearate, gelatin, talc, wheat starch.
Tablet Appearance and Pack Sizes
| Product | Appearance | Imprint | Diameter | Pack Sizes |
|---|---|---|---|---|
| Sparkal | Pale yellow, round, flat tablet with score line | EV 7 (one side) / GEA (other side) | 8.5 mm | 30, 100, 250 tablets |
| Sparkal Mite | Pale yellow, round, flat tablet with score line | EZ 3 (one side) / GEA (other side) | 7 mm | 30, 100, 250 tablets |
Both products are supplied in polyethylene tablet containers. Not all pack sizes may be marketed in your country.
Marketing Authorization Holder: Hexal A/S, Edvard Thomsens Vej 14, 2300 Copenhagen S, Denmark.
Frequently Asked Questions About Sparkal
Sparkal is a combination diuretic containing amiloride hydrochloride and hydrochlorothiazide. It is used to treat high blood pressure (hypertension), edema caused by heart failure, and fluid retention associated with liver cirrhosis (ascites). The amiloride component helps preserve potassium and magnesium levels that would otherwise be depleted by hydrochlorothiazide alone, making it a safer option for long-term diuretic therapy.
Sparkal contains 5 mg amiloride hydrochloride and 50 mg hydrochlorothiazide per tablet. Sparkal Mite is a lower-strength version containing half the dose: 2.5 mg amiloride hydrochloride and 25 mg hydrochlorothiazide. Sparkal Mite is typically prescribed for hypertension, while the full-strength Sparkal is often used as a starting dose for edema in heart failure or liver cirrhosis. One Sparkal tablet is equivalent to two Sparkal Mite tablets.
Yes. Because amiloride is a potassium-sparing diuretic, Sparkal can cause hyperkalemia (high blood potassium levels), especially in patients with kidney impairment, diabetes, or those simultaneously taking ACE inhibitors, ARBs, or potassium supplements. Symptoms of hyperkalemia include muscle weakness, fatigue, confusion, speech difficulties, and irregular heartbeat. Regular blood tests to monitor potassium levels are essential during treatment with Sparkal.
Sparkal is not recommended during pregnancy. The hydrochlorothiazide component crosses the placenta and may cause harm to the fetus, particularly during the last six months of pregnancy. Potential risks include electrolyte imbalances in the newborn, reduced placental blood flow, and neonatal jaundice. Your doctor will typically switch you to a safer alternative if you become pregnant or are planning pregnancy. Always discuss medication safety with your healthcare provider before conceiving.
While taking Sparkal, you should limit foods very high in potassium unless your doctor advises otherwise. These include bananas, oranges, potatoes, tomatoes, dried fruits, and salt substitutes containing potassium chloride. Because amiloride reduces potassium excretion, consuming large amounts of potassium-rich foods can increase the risk of hyperkalemia. You should also minimize alcohol consumption, as alcohol can enhance the blood-pressure-lowering effect of Sparkal and increase the risk of dizziness, particularly when standing up quickly.
Sparkal tablets contain wheat starch as an inactive ingredient, but the gluten content is extremely low. One Sparkal tablet contains no more than 8.3 micrograms of gluten, and one Sparkal Mite tablet no more than 4.2 micrograms. These amounts are very unlikely to cause problems for people with celiac disease. However, if you have a true wheat allergy (which is a separate condition from celiac disease), you should not take Sparkal and should discuss alternative medications with your doctor.
References
- European Medicines Agency (EMA). Summary of Product Characteristics: Amiloride/Hydrochlorothiazide combination products. EMA Product Information Database. Accessed January 2026.
- British National Formulary (BNF). Amiloride with hydrochlorothiazide. NICE Evidence Services. Updated December 2025.
- Williams B, Mancia G, Spiering W, et al. 2018 ESC/ESH Guidelines for the management of arterial hypertension. European Heart Journal. 2018;39(33):3021-3104. doi:10.1093/eurheartj/ehy339
- National Institute for Health and Care Excellence (NICE). Hypertension in adults: diagnosis and management [NG136]. Updated March 2025.
- World Health Organization (WHO). Model List of Essential Medicines – 23rd edition. Geneva: WHO; 2023.
- Sica DA. Diuretic-related side effects: development and treatment. Journal of Clinical Hypertension. 2004;6(9):532-540. doi:10.1111/j.1524-6175.2004.03789.x
- Pitt B, Rossignol P. Potassium-sparing diuretics: from cardioprotection to renoprotection. European Heart Journal. 2019;40(39):3236-3238. doi:10.1093/eurheartj/ehz557
- Pedersen SA, Gaist D, Schmidt SAJ, et al. Hydrochlorothiazide use and risk of nonmelanoma skin cancer. Journal of the American Academy of Dermatology. 2018;78(4):673-681.e9. doi:10.1016/j.jaad.2017.11.042
- European Medicines Agency (EMA). Pharmacovigilance Risk Assessment Committee (PRAC) recommendations on hydrochlorothiazide and skin cancer risk. 2018.
- Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Journal of the American College of Cardiology. 2018;71(19):e127-e248.
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, comprising specialist physicians with expertise in internal medicine, cardiology, nephrology, and clinical pharmacology.
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