Minoxidil (Loniten) is a drug that causes vasodilation. It is rarely used in the management of hypertension in patients resistant to a diuretic and two other antihypertensive medications.

Minoxidil (Loniten) Uses:

• Hypertension:

  • It is suggested for the treatment of symptomatic hypertension or that which is linked to target organ damage, resistance to a diuretic, and the use of two additional antihypertensives.
  • Not recommended in milder hypertension because the benefit-risk ratio is not defined.

Note: It is not suggested to be used as an initial treatment for high blood pressure.

Minoxidil Dose in Adults:

Minoxidil (Loniten) Dose as an alternative agent in the treatment of Hypertension:

• Oral: Initial:5 mg once a day, which may be gradually increased every three days or more in dosages of 1 to 3. (or every 6 hours with careful monitoring if rapid management is required)
• Maximum dose: 100 mg/day

Note: When adding the medication as a concurrent therapy, adjust the dosage. Give the dose once daily if the patient's supine diastolic pressure is below 30 mm Hg; give the dose in two equally spaced doses if it is above 30 mm Hg.

Minoxidil Dose in Children:

Minoxidil (Loniten) Dose in the therapy of extremely high blood pressure; resistant to multiple drugs:

• Children <12 years:

  • The usual effective dosage is 0.25 to 1 mg/kg/day, split into 1 to 3 doses.
  • Initial: 0.2 mg/kg/dose once a daily
  • Maximum initial dose: 5 mg/dose; titrate to effect, may increase the daily dose by 50% to 100% every 3 days;
  • Can be divided up to 1 - 3 times daily
  • Maximum daily dose: 50 mg/day

Note: In situations where rapid blood pressure management is required, the dose can be increased every 6 hours with careful monitoring.

• Children ≥12 years and Adolescents:

  • The usual effective dosage range is 10 to 40 mg per day, split into 1 to 3 doses.
  • Initial: 5 mg once a day, titrate to effect, can be increased every 3 days by doubling the daily dose (10 mg/day, 20 mg/day, and then 40 mg/day)
  • Can be divided up to 1 - 3 times daily
  • Maximum dose: 100 mg/day

Note: In situations where rapid blood pressure management is required, the dose can be increased every 6 hours with careful monitoring.

Pregnancy Risk Factor C

• Studies on animals have shown adverse effects.
• Neonatal hypertrichosis is possible

Use during breastfeeding:

• Breast milk can contain minoxidil.
• Due to possible side effects, the manufacturer doesn't recommend breastfeeding.

Dose in Kidney Disease:

The manufacturer has not provided any dose adjustment in labeling However, reduce the dose in renal failure and/or receiving dialysis.

Dose in Liver disease:

The manufacturer has not provided any dose adjustment in labeling Use cautiously and titrates gradually (minoxidil AUC increased by 50% and its clearance decreased in mildly cirrhotic patients.

Side effects of Minoxidil (Loniten):

• Dermatologic:

  • Toxic Epidermal Necrolysis
  • Skin Rash
  • Hypertrichosis
  • Bullous Rash
  • Stevens-Johnson Syndrome

• Cardiovascular:

  • ECG Changes
  • Edema
  • Pericardial Effusion
  • Angina Pectoris
  • Cardiac Failure
  • Pericarditis
  • Tachycardia

• Endocrine & Metabolic:

  • Sodium Retention
  • Water Retention
  • Weight Gain

• Gastrointestinal:

  • Nausea
  • Vomiting

• Hematologic & Oncologic:

  • Hemoglobin
  • Leukopenia
  • Decreased Hematocrit
  • Decreased Red Blood Cells
  • Thrombocytopenia

• Respiratory:

  • Pulmonary Edema

• Hepatic:

  • Ascites
  • Increased Serum Alkaline Phosphatase

• Renal:

  • Increased Blood Urea Nitrogen
  • Increased Serum Creatinine

Contraindications to Minoxidil (Loniten):

• Hypersensitivity to any formulation's component
• Pheochromocytoma

Canadian labeling: Additional contraindications not in US labeling

• Pulmonary hypertension due to mitral stenosis (MS),
• Hepatic impairment severe

Warnings and precautions

• Fluid retention:

  • Salt and water retention can result from their use
  • To avoid fluid overload, use loop diuretics or diuretic diuretics
  • Patients with heart failure should exercise extreme caution

• Pericardial effusion/tamponade [US Boxed Warn]

  • Its use can cause pericarditis or pericardial effusion, which could lead to tamponade.
  • Patients at greater risk of renal impairment are those with higher incomes.
  • In the event of heart failure, be cautious
  • Pay attention to the patient
  • Minoxidil should be stopped if there is persistent effusion.

• Control blood pressure quickly

  • Syncope, cerebrovascular accident, myocardial infarction, and ischemia of any other organs, which can cause visual or hearing loss, can all happen from abruptly dropping blood pressure.
  • Minoxidil may cause ischemic episodes in organs if it is used with compromised circulation and cryoglobulinemia.

• Sinus tachycardia [US Boxed Warning]

  • Its use can increase oxygen demand and worsen angina pectoris.
  • If there is no contraindication, a beta-blocker should also be taken with it.
  • Ischemic heart disease: Use caution

• Acute myocardial injury (MI)

  • Its use can increase oxygen demand and reflex Tachycardia. Avoid its use for at least one month following a myocardial Infarction event
  • It is a good idea to take extreme caution. Before starting therapy, ensure that the patient has taken a beta-blocker.

• Heart failure:

  • Minoxidil caused an increase in diuretics, angina, and ventricular arrhythmias. It also increased the risk of death.
  • Minoxidil, according to the American Heart Association (AHA), can cause myocardial dysfunction.

• Renal impairment

  • Avoid renal impairment. In renal failure or dialysis, a smaller dose may be required.
  • To prevent further kidney damage, monitor closely.

Minoxidil (topical): Drug Interaction

Monitoring parameters:

• Fluid and electrolyte balance
• Signs/symptoms of pericardial effusion
• Bodyweight monitoring.
• When starting treatment, keep track of any abnormal results from tests such as renal function tests, ECGs, echocardiograms, and chest X-rays. Repeat the tests first every 1 to 3 months, then every 6 to 12 months until the condition is stabilized.
• Blood pressure, standing and sitting/supine

According to the 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults :

• Confirmed hypertension and known CVD or 10-year ASCVD risk ≥10%: Target blood pressure <130/80 mm Hg is recommended
• Confirmed hypertension without markers of increased ASCVD risk: Target blood pressure <130/80 mm Hg may be reasonable

Mechanism of action of Minoxidil (Loniten):

• It directly acts on the arterial smooth muscles, relaxes them, and induces vasodilation. 
• It does not affect veins. The cyclic AMP is responsible for its action. 
• Vasodilation is responsible for stimulating hair growth.
• This increases cutaneous blood flow and stimulates resting hair cells.

The beginning of action:

• Hypotensive: ~30 minutes

Peak effect:

• 2 - 3 hours

Half-life elimination:

• 3.5 - 4.2 hours

Duration:

• Up to 2 - 5 days

Protein binding:

• None

Metabolism:

• About 90%, mainly via glucuronidation

Bioavailability:

• 90%

Excretion:

• Urine (12% excretes unchanged)

International Brand Names of Minoxidil:

• Loniten
• Guayaten
• Loniten
• Lonnoten
• Lonolox
• Lonoten
• Manoxidil
• Midil
• Noxidil
• Noxidil Forte

Minoxidil Brands Names in Pakistan:

Systemic minoxidil is not available in Pakistan. The common formulation is the topical solution and sprays used for hair growth.