Minoxidil 2.5mg Tablets
WARNING: This drug may cause very bad heart-related side effects. This includes chest pain that gets worse. This drug is only for use when blood pressure is not controlled by other drugs. Talk with the doctor.You will need to take certain other drugs with this drug to prevent side effects. If you have questions, talk with your doctor.Sometimes, this drug will need to be started in a hospital where you will be closely watched. Talk with your doctor. @ COMMON USES: It is used to treat high blood pressure.
Drug Class
Antihypertensive
Pharmacologic Class
Peripheral Vasodilator; Potassium Channel Opener
Pregnancy Category
C
FDA Approved
Aug 1979
DEA Schedule
Not Controlled
Overview
What is this medicine?
Minoxidil is a medication used to treat very high blood pressure (hypertension) that has not responded to other medicines. It works by relaxing and widening blood vessels, allowing blood to flow more easily. Because it can cause side effects like fluid retention and a fast heartbeat, it is usually taken with other medications, such as a water pill (diuretic) and a beta-blocker.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, it's essential to use it as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets, to prevent accidental ingestion or misuse.
What to Do If You Miss a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, it's essential to use it as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets, to prevent accidental ingestion or misuse.
What to Do If You Miss a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take exactly as prescribed, usually with a diuretic and a beta-blocker.
- Do not stop taking minoxidil suddenly without consulting your doctor, as this can cause a rapid increase in blood pressure.
- Monitor your blood pressure and heart rate regularly at home, if advised by your doctor.
- Weigh yourself daily and report any sudden weight gain (e.g., more than 2-3 kg in a week) or swelling in your ankles, feet, or hands to your doctor immediately.
- Limit sodium intake as advised by your doctor to help manage fluid retention.
- Report any new or worsening chest pain, shortness of breath, or dizziness.
- Be aware of potential increased hair growth on the body (hirsutism), which is a common side effect.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 5 mg orally once daily, may be increased gradually.
Dose Range:
2.5 - 100 mg
Condition-Specific Dosing:
severeHypertension:
Initial 5 mg orally once daily. May be increased to 10 mg, 20 mg, and then 40 mg in single or divided doses at 3-day or longer intervals until optimal blood pressure control is achieved. Usual effective dose range is 10-40 mg/day. Maximum dose is 100 mg/day.
Pediatric Dosing
Neonatal:
Not established for routine use. Used off-label for severe refractory hypertension under specialist supervision, typically 0.2 mg/kg/day initially, titrated up to 1 mg/kg/day (max 50 mg/day).
Infant:
Not established for routine use. Used off-label for severe refractory hypertension under specialist supervision, typically 0.2 mg/kg/day initially, titrated up to 1 mg/kg/day (max 50 mg/day).
Child:
Not established for routine use. Used off-label for severe refractory hypertension under specialist supervision, typically 0.2 mg/kg/day initially, titrated up to 1 mg/kg/day (max 50 mg/day).
Adolescent:
Not established for routine use. Used off-label for severe refractory hypertension under specialist supervision, typically 0.2 mg/kg/day initially, titrated up to 1 mg/kg/day (max 50 mg/day).
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment generally required, but monitor for fluid retention.
Moderate:
Consider starting with a lower dose (e.g., 2.5 mg/day) and titrate slowly. Monitor closely for fluid retention and electrolyte imbalances.
Severe:
Consider starting with a lower dose (e.g., 2.5 mg/day) and titrate slowly. Monitor closely for fluid retention and electrolyte imbalances. Often requires concomitant diuretic.
Dialysis:
Minoxidil and its metabolites are dialyzable. Administer dose after dialysis. Start with lower doses and titrate carefully.
Hepatic Impairment:
Mild:
No specific dose adjustment generally required.
Moderate:
Use with caution. Consider starting with a lower dose (e.g., 2.5 mg/day) and titrate slowly due to hepatic metabolism.
Severe:
Use with caution. Consider starting with a lower dose (e.g., 2.5 mg/day) and titrate slowly due to hepatic metabolism. Monitor for adverse effects.
Pharmacology
Mechanism of Action
Minoxidil is a direct-acting peripheral vasodilator that reduces elevated systolic and diastolic blood pressure by decreasing peripheral vascular resistance. It acts by opening ATP-sensitive potassium channels in vascular smooth muscle cells, leading to hyperpolarization and relaxation of the smooth muscle, primarily in arterioles. This vasodilation leads to a reflex increase in heart rate and cardiac output, and increased renin secretion, which can lead to fluid and salt retention.
Pharmacokinetics
Absorption:
Bioavailability:
90-100%
Tmax:
1 hour
FoodEffect:
Not significantly affected by food.
Distribution:
Vd:
2.8 L/kg
ProteinBinding:
<20%
CnssPenetration:
Limited
Elimination:
HalfLife:
3-4.2 hours (plasma elimination half-life); however, the pharmacodynamic effect (blood pressure lowering) can persist for up to 24 hours due to tissue binding and active metabolite.
Clearance:
Not available
ExcretionRoute:
Renal (approximately 90% as metabolites and unchanged drug)
Unchanged:
10-12%
Pharmacodynamics
OnsetOfAction:
Within 30 minutes
PeakEffect:
2-3 hours
DurationOfAction:
Up to 24 hours
Safety & Warnings
BLACK BOX WARNING
Minoxidil can cause serious adverse effects, including pericardial effusion, occasionally progressing to tamponade, and angina pectoris exacerbation. Fluid and salt retention, leading to edema and congestive heart failure, are common. Minoxidil must be administered under close supervision, usually with a concomitant diuretic to prevent fluid retention and a beta-adrenergic blocking drug (or other sympathetic nervous system suppressant) to prevent tachycardia and angina.
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Shortness of breath
New or worsening chest, arm, or shoulder pain
Dizziness or fainting
Fast or abnormal heartbeat
Severe or persistent heartburn
Changes in hearing or eyesight
Additionally, this medication may cause fluid retention, leading to swelling, weight gain, or breathing difficulties. If you notice any of these symptoms, inform your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor:
Excessive hair growth
* Upset stomach or vomiting
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Shortness of breath
New or worsening chest, arm, or shoulder pain
Dizziness or fainting
Fast or abnormal heartbeat
Severe or persistent heartburn
Changes in hearing or eyesight
Additionally, this medication may cause fluid retention, leading to swelling, weight gain, or breathing difficulties. If you notice any of these symptoms, inform your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor:
Excessive hair growth
* Upset stomach or vomiting
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Sudden, unexplained weight gain
- Swelling of the ankles, feet, or hands (edema)
- Shortness of breath, especially when lying down
- Chest pain or discomfort (angina)
- Rapid or irregular heartbeat (palpitations)
- Dizziness or lightheadedness
- Fainting spells
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
If you have been diagnosed with pheochromocytoma, a type of adrenal gland tumor.
If you have recently experienced a heart attack.
If you are breastfeeding. Note that you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication in combination with your other treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
If you have been diagnosed with pheochromocytoma, a type of adrenal gland tumor.
If you have recently experienced a heart attack.
If you are breastfeeding. Note that you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe to take this medication in combination with your other treatments and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you.
When getting up from a sitting or lying down position, rise slowly to minimize the risk of dizziness or fainting. Be cautious when climbing stairs to prevent accidents.
As directed by your doctor, regularly monitor your blood pressure and heart rate. Before starting this medication and during treatment, you will need to undergo heart checks, including an electrocardiogram (ECG). Discuss any concerns or questions with your doctor.
Follow your doctor's instructions for having your blood work and other laboratory tests checked.
Weigh yourself daily and consult your doctor before taking any over-the-counter (OTC) products that may increase blood pressure, such as cough or cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids.
If you are pregnant or planning to become pregnant, inform your doctor. You will need to discuss the benefits and risks of using this medication during pregnancy to make an informed decision.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you.
When getting up from a sitting or lying down position, rise slowly to minimize the risk of dizziness or fainting. Be cautious when climbing stairs to prevent accidents.
As directed by your doctor, regularly monitor your blood pressure and heart rate. Before starting this medication and during treatment, you will need to undergo heart checks, including an electrocardiogram (ECG). Discuss any concerns or questions with your doctor.
Follow your doctor's instructions for having your blood work and other laboratory tests checked.
Weigh yourself daily and consult your doctor before taking any over-the-counter (OTC) products that may increase blood pressure, such as cough or cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids.
If you are pregnant or planning to become pregnant, inform your doctor. You will need to discuss the benefits and risks of using this medication during pregnancy to make an informed decision.
Overdose Information
Overdose Symptoms:
- Profound hypotension (very low blood pressure)
- Tachycardia (rapid heart rate)
- Fluid retention
- Congestive heart failure
What to Do:
Seek immediate medical attention. Treatment is supportive and symptomatic. Intravenous normal saline may be administered to maintain blood pressure. Vasopressors (e.g., norepinephrine) may be used if severe hypotension persists. Dialysis can remove minoxidil and its metabolites. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Major Interactions
- Guanethidine (severe orthostatic hypotension)
- Other antihypertensives (additive hypotensive effects)
Moderate Interactions
- Diuretics (may enhance hypotensive effect and fluid retention)
- Beta-blockers (used concomitantly to control reflex tachycardia, but monitor for excessive bradycardia)
- NSAIDs (may reduce antihypertensive effect due to fluid retention)
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation.
Heart Rate (HR)
Rationale: To establish baseline and monitor for reflex tachycardia.
Timing: Prior to initiation.
Weight and Fluid Status
Rationale: To assess for fluid retention/edema, a common side effect.
Timing: Prior to initiation.
Renal Function (BUN, Creatinine)
Rationale: To assess kidney function and guide dosing in renal impairment.
Timing: Prior to initiation.
Electrolytes (Sodium, Potassium)
Rationale: To assess baseline and monitor for imbalances, especially with concomitant diuretic use.
Timing: Prior to initiation.
Electrocardiogram (ECG)
Rationale: To assess for baseline cardiac abnormalities, especially in patients with pre-existing heart disease.
Timing: Prior to initiation.
Routine Monitoring
Blood Pressure (BP)
Frequency: Daily initially, then regularly (e.g., weekly or bi-weekly) until stable, then periodically.
Target: Individualized, typically <130/80 mmHg or as per clinical guidelines.
Action Threshold: If BP remains uncontrolled or drops excessively.
Heart Rate (HR)
Frequency: Daily initially, then regularly (e.g., weekly or bi-weekly) until stable, then periodically.
Target: Individualized, typically 60-80 bpm.
Action Threshold: If persistent tachycardia (>90 bpm) or bradycardia (<50 bpm).
Weight and Fluid Status (Edema)
Frequency: Daily initially, then weekly, then periodically.
Target: Stable weight, no significant edema.
Action Threshold: Sudden weight gain (>2-3 kg/week) or new/worsening edema.
Renal Function (BUN, Creatinine)
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated).
Target: Within normal limits or stable for patient's baseline.
Action Threshold: Significant increase in BUN/Creatinine.
Electrolytes (Sodium, Potassium)
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated), especially with diuretic use.
Target: Within normal limits.
Action Threshold: Significant abnormalities.
Electrocardiogram (ECG)
Frequency: Periodically (e.g., annually or as clinically indicated), especially in patients with cardiac history.
Target: No significant changes or new abnormalities.
Action Threshold: New or worsening ischemic changes, pericardial effusion.
Symptom Monitoring
- Chest pain (angina)
- Shortness of breath (dyspnea)
- Swelling of ankles, feet, or hands (edema)
- Rapid heart beat (palpitations)
- Dizziness or lightheadedness
- Unexplained weight gain
- New or worsening hair growth (hirsutism)
Special Patient Groups
Pregnancy
Minoxidil is Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There are reports of fetal harm (e.g., hypertrichosis, anencephaly) in animal studies and limited human data.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm, as organogenesis occurs during this period. Limited human data.
Second Trimester:
Potential for fetal harm, including hypertrichosis (excessive hair growth) in the fetus.
Third Trimester:
Potential for fetal harm, including hypertrichosis in the fetus. May affect fetal circulation.
Lactation
Minoxidil is excreted into breast milk. The amount is small, but potential effects on the infant are unknown. Use with caution; monitor the infant for adverse effects (e.g., hypotension, tachycardia). L3 (moderately safe) rating suggests that while there is some data, the risk is low but not negligible.
Infant Risk:
Low to moderate risk. Monitor for hypotension, tachycardia, and changes in hair growth.
Pediatric Use
Minoxidil is not approved for routine pediatric use but is used off-label for severe, refractory hypertension in children under specialist supervision. Dosing is weight-based and requires careful titration and monitoring due to the risk of significant side effects (e.g., fluid retention, tachycardia, pericardial effusion).
Geriatric Use
No specific dose adjustment is generally required based on age alone, but elderly patients may be more sensitive to the hypotensive effects and more prone to fluid retention and other cardiovascular side effects. Start with lower doses and titrate slowly. Monitor closely for adverse effects.
Clinical Information
Clinical Pearls
- Minoxidil is a potent vasodilator and should almost always be used in combination with a diuretic (to prevent fluid retention and edema) and a beta-blocker or other sympathetic nervous system suppressant (to prevent reflex tachycardia and angina).
- Patients should be educated on the importance of daily weight monitoring and reporting any sudden weight gain or swelling.
- Hirsutism (excessive hair growth) is a very common and often bothersome side effect, occurring in up to 80% of patients, particularly women and children. It is reversible upon discontinuation but may take several months.
- The 2.5 mg tablet is often used for initial titration or in patients requiring lower doses, especially those with renal impairment or who are elderly.
- Due to its significant side effect profile, minoxidil is typically reserved for severe, refractory hypertension that has not responded to other antihypertensive agents.
Alternative Therapies
- Other classes of antihypertensives for severe hypertension: ACE inhibitors (e.g., lisinopril), Angiotensin Receptor Blockers (ARBs, e.g., valsartan), Calcium Channel Blockers (e.g., amlodipine), Alpha-blockers (e.g., prazosin), Loop diuretics (e.g., furosemide), Beta-blockers (e.g., carvedilol, labetalol).
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (2.5mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.