Adult Dosing

Severe hypertension

• Start 5 mg PO qd; may increase the dose to 10, 20, and then to 40 mg in single or divided doses, if indicated
• Usual dose range: 10-40 mg/day
• Max: 100 mg/day

Note:

• If supine diastolic pressure reduces <30 mmHg, administer the drug qd
• If supine diastolic pressure reduces >30 mmHg, divide the dose into 2 equal parts
• Dose adjustment intervals should be at least 3 days. When rapid management of hypertension is required, adjust the dose q6 hrs if the patient is carefully monitored

Concomitant therapy with a diuretic, beta-blocker or other sympathetic nervous system suppressant

• Diuretics: This combination must be used in patients relying on renal function for maintaining salt and water balance
• When starting therapy with minoxidil, diuretics have been used at the following dosages: Hydrochlorothiazide - 50 mg bid or other thiazides at equi-effective dosage; furosemide - 40 mg bid, chlorthalidone - 50 to 100 mg qd
• If excessive salt and water retention causes a weight gain of >5 pounds, diuretic should be changed to furosemide or if furosemide is already being used, dose should be titrated as necessary
• Beta-blocker: After starting minoxidil therapy, beta-adrenergic receptor blocking agent equivalent to 80-160 mg/day of propranolol in divided doses should be used; when beta-blockers are contraindicated, methyldopa 250 to 750 mg bid may be given. Methyldopa should be given at least 24 hrs prior to initiating minoxidil therapy
• Sympathetic nervous system suppressants may not fully prevent an increase in heart rate associated with minoxidil but usually do prevent tachycardia

Pediatric Dosing

Severe hypertension

<12 yrs

• Start 0.2 mg/kg PO qd; may increase the dose in 50-100% increments until optimum blood pressure control is achieved
• Usual dose range: 0.25-1 mg/kg/day
• Max: 50 mg/day

12 yrs

• Start 5 mg PO qd; may increase the dose to 10, 20, and then to 40 mg in single or divided doses, if indicated
• Usual dose range: 10-40 mg/day
• Max: 100 mg/day

Note:

• If supine diastolic pressure reduces <30 mmHg, administer the drug qd
• If supine diastolic pressure reduces >30 mmHg, divide the dose into 2 equal parts
• Dose adjustment intervals should be at least 3 days. When rapid management of hypertension is required, adjust the dose q6 hrs if the patient is carefully monitored

Concomitant therapy with a diuretic, beta-blocker or other sympathetic nervous system suppressant

• Diuretics: This combination must be used in patients relying on renal function for maintaining salt and water balance
• When starting therapy with minoxidil, diuretics have been used at the following dosages: Hydrochlorothiazide - 50 mg bid or other thiazides at equi-effective dosage; furosemide - 40 mg bid, chlorthalidone - 50 to 100 mg qd
• If excessive salt and water retention causes a weight gain of >5 pounds, diuretic should be changed to furosemide or if furosemide is already being used, dose should be titrated as necessary
• Beta-blocker: After starting minoxidil therapy, beta-adrenergic receptor blocking agent equivalent to 80-160 mg/day of propranolol in divided doses should be used; when beta-blockers are contraindicated, methyldopa 250 to 750 mg bid may be given. Methyldopa should be given at least 24 hrs prior to initiating minoxidil therapy
• Sympathetic nervous system suppressants may not fully prevent an increase in heart rate associated with minoxidil but usually do prevent tachycardia

[Outline]

• Adult Dosing
• Pediatric Dosing

• Treatment of severe hypertension that is symptomatic or associated with target organ damage and is not manageable with maximum therapeutic doses of a diuretic plus two other antihypertensive drugs

• Hypersensitivity to any of the ingredients of the product
• Pheochromocytoma
• Pericardial effusion

• Powerful antihypertensive agent, which may produce serious adverse events including pericardial effusion, sometimes progressing to tamponade and exacerbation of angina pectoris
• Minoxidil therapy should be reserved for hypertensive patients who do not respond adequately to maximum therapeutic doses of a diuretic and two other antihypertensive agents
• Minoxidil use caused several kinds of myocardial lesions and other adverse cardiac events in experimental animals
• Should be administered under close supervision, usually in combination with effective doses of a beta-adrenergic blocker to prevent tachycardia and increased myocardial workload. Minoxidil must also be given with a diuretic to prevent serious fluid accumulation. Hospitalization is indicated in patients already receiving guanethidine and those with malignant hypertension, so that they can be monitored to avoid too rapid, or large orthostatic, decreases in blood pressure

Renal Dose Adjustments

• Renal impairment: No dose adjustments
• Renal failure: Decrease the dose with caution

Hepatic Dose Adjustments

• Hepatic impairment: Dose adjustments not defined

See Supplemental Patient Information

• To prevent fluid retention and possible CHF, minoxidil must be co-administered with a diuretic. Monitor fluid and electrolyte balance and body weight. To minimize fluid retention, diuretic alone or in combination with restricted salt intake is usually necessary; sometimes discontinuation of minoxidil for 1-2 days and then resuming therapy in combination with vigorous diuretic therapy may be required in case of refractory fluid retention
• Minoxidil may cause tachycardia and angina for the first time or exacerbation of preexisting angina; this can be prevented by concomitant use of a beta-blocker or other sympathetic nervous system suppressant
• Incidence of pericarditis has been reported with minoxidil use. Pericardial effusion, sometimes with tamponade, may occur in patients with inadequate or compromised renal function. Although pericardial effusion is usually associated with a connective tissue disease, the uremic syndrome, CHF, or marked fluid retention; there have been cases without these potential causes of effusion. Monitor closely for any signs of pericardial disorder
• Minoxidil in combination with guanethidine may cause profound orthostatic hypotension. Discontinue guanethidine if possible well before starting minoxidil therapy. Where discontinuation is not possible, minoxidil therapy should be initiated in the hospital
• Patients already receiving guanethidine and those with malignant hypertension should be hospitalized when minoxidil is first administered so that they can be monitored to avoid too rapid, or large orthostatic, decreases in blood pressure. Too rapid control of blood pressure in patients with severe hypertension may precipitate syncope, cerebrovascular accidents, MI, and ischemia of special sense organs with resulting loss of vision or hearing [US Black Box Warning]
• Hypersensitivity reactions including a skin rash may occur in some patients
• Laboratory tests which were abnormal at the time of initiation of therapy, such as urinalysis, renal function tests, EKG, chest x-ray, and echocardiogram should be repeated initially at 1-3 month intervals, later as condition stabilizes, and at intervals of 6-12 months, to measure the improvement or deterioration during therapy

Cautions: Use cautiously in

• Renal impairment
• Acute MI

Supplemental Patient Information

• Instruct patients to promptly inform their physicians if they experience an increased heart rate, rapid weight gain (>5 pounds), increased difficulty in breathing while lying down, signs of severe indigestion; worsening pain in the chest, arm or shoulder; dizziness, lightheadedness or fainting

Pregnancy Category:C

Breastfeeding: Because of the minimal amount of information on this drug, caution should be exercised, particularly when using large doses or in newborns. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 28 April 2011). As per manufacturer's data, minoxidil has been reported to be excreted in breast milk in some cases. Because of the potential for adverse events in breast fed infants, minoxidil should not be administered to nursing women.

• CV: Pericarditis, pericardial effusion, tamponade, CHF, angina exacerbation
• METABOLIC: Salt and water retention, weight gain, temporary edema
• GI: Nausea, vomiting
• DERM: Hypertrichosis, rashes, bullous eruptions, Stevens-Johnson syndrome
• HEMA: Thrombocytopenia, leukopenia
• LABTEST: ECG changes; reductions in hematocrit, hemoglobin and erythrocyte count; elevated alkaline phosphatase and serum creatinine

• Anti-hypertensive; reduces elevated systolic and diastolic blood pressure by decreasing peripheral vascular resistance
• Metabolized predominantly in the liver
• Excreted extensively in urine
• Half-life: 4.2 hrs

US Trade Name(s)

• Only generic available

US Availability

minoxidil (generic)

• TABS: 2.5, 10 mg

Canadian Trade Name(s)

• Loniten

Canadian Availability

Loniten

• TABS: 2.5, 10 mg

UK Trade Name(s)

• Loniten

UK Availability

Loniten

• TABS: 2.5, 5, 10 mg

Australian Trade Name(s)

• Loniten

Australian Availability

Loniten

• TABS: 10 mg

[Outline]

Cardiovascular

Antihypertensive Agents

Peripheral Vasodilators

• Loniten 10 MG Oral Tablet (Pharmacia and Upjohn Company)
• Loniten 2.5 MG Oral Tablet (Pharmacia and Upjohn Company)
• Minoxidil 10 MG Oral Tablet (Mutual Pharmaceutical Company, Inc.)
• Minoxidil 10 MG Oral Tablet (Par Pharmaceutical Inc)
• Minoxidil 10 MG Oral Tablet (State of Florida DOH Central Pharmacy)
• Minoxidil 10 MG Oral Tablet (Watson Laboratories, Inc.)
• Minoxidil 2.5 MG Oral Tablet (Mutual Pharmaceutical Company, Inc.)
• Minoxidil 2.5 MG Oral Tablet (NCS HealthCare of KY, Inc dba Vangard Labs)
• Minoxidil 2.5 MG Oral Tablet (Par Pharmaceutical Inc)
• Minoxidil 2.5 MG Oral Tablet (State of Florida DOH Central Pharmacy)
• Minoxidil 2.5 MG Oral Tablet (Watson Laboratories, Inc.)