minoxidil

Minoxidil

 

Definition

Minoxidil is a drug available in two forms to treat different conditions. Oral minoxidil is used to treat high blood pressure and the topical solution form is used to treat hair loss and baldness.

Purpose

Minoxidil was the first drug approved by the FDA for the treatment of androgenetic alopecia (hair loss). Before that, minoxidil had been used as vasodilator drug prescribed as oral tablet to treat high blood pressure, with side effects that included hair growth and reversal of male baldness. In the 1980s, UpJohn Corporation came out with a topical solution of 2% minoxidil, called Rogaine, for the specific treatment of androgenetic alopecia. Since the 1990s, numerous generic forms of minoxidil have become available to treat hair loss while the oral form is still used to treat high blood pressure.

The popularity hair loss treatment is due to the general preference in the overall population for the cosmetic appearance of a full head of hair. Minoxidil is used to stimulate hair growth in areas of the scalp that have stopped growing hair. As of early 2001, the exact mechanism of action of minoxidil is not known.

Precautions

People who have had a prior unusual or allergic reaction to either minoxidil or propylene glycol, a non-active chemical in the Rogaine solution, should not use topical minoxidil. People who have had a previous allergic reaction to preservatives or dyes may also be at risk for having an allergic reaction to minoxidil.

People who are using cortisone, or cortisone-like drugs (corticosteroids), petroleum jelly (Vaseline), or tretinoin (Retin-A) on their scalps should consult their doctors prior to using minoxidil. The use of any of these products in conjunction with minoxidil may cause excessive minoxidil absorption into the body and increase the risk of side effects.

Also, people who have skin problems or irritations of the scalp, including sunburn, may absorb too much minoxidil and increase their risk of side effects.

As for oral minoxidil, the form prescribed for high blood pressure, patients should use minoxidil only under medical supervision to ensure that excessive amounts of the drug are not absorbed into their bodies. Large amounts of minoxidil may increase the severity of the symptoms and side effects of hypertension.

Minoxidil may pass from mother to child through breast milk. Therefore, women who are breastfeeding should not use minoxidil.

Description

For the treatment of hair loss, minoxidil is available as a topical solution that is generally either 2% or 5% minoxidil in propylene glycol. The propylene glycol ensures that the applied minoxidil is evenly spread across the affected area and easily absorbed through the skin. As of early 2001, the 5% solution is only approved by the FDA for use on men. Approximately 1 milliliter of minoxidil solution is applied to the scalp once a day using the fingertips or a pump spray. It should be applied from the center of the area being treated outward.

In the treatment of high blood pressure, oral minoxidil is usually prescribed when other medications have failed to treat the condition. Dosage is usually 2.5-100 mg per day as a single dose for adults and 200 micrograms to 1 mg per kg of body weight for children.

Preparation

Before using topical minoxidil, the hair and scalp should be clean and dry before the minoxidil solution is applied.

Aftercare

Hands, and any other areas of the body where hair growth is not desired that may have come into contact with topical minoxidil, should be washed immediately after applying the minoxidil solution on the scalp. Once applied, topical minoxidil should be allowed to air-dry for at least two to four hours before clothing are pulled on or off over the head, a hat is worn, or the patient goes to bed. Prior to this, the minoxidil solution may stain clothing, hats, or bed linens; or, it may be accidentally transferred from the patient's head to one of these objects, then back to other parts of the patient's body where hair growth is not desired. A blow dryer, or other drying methods, should not be used to speed the drying of the minoxidil as this may interfere with the absorption of the medicine. People using minoxidil should also not shampoo, wash, or rinse their hair for at least 4 hours after minoxidil is applied.

Risks

The most common side effects of topical minoxidil use are itching and skin irritation of the treated area of the scalp. Unwanted hair growth may also occur adjacent to treated areas or in areas where the medicine has been inadvertently transferred several times. This unwanted hair growth adjacent to the treatment area may be particularly distressing to women when the face is involved. The itching and irritation usually subside after the drug has been used for approximately two weeks. If symptoms persist after this time, minoxidil use should be halted until a physician has been consulted.

Extremely rare side effects that may occur if too much topically or orally administered minoxidil is being absorbed in the body include:

• changes in vision, most commonly blurred vision
• chest pain
• very low blood pressure
• decreased sexual desire
• fast or irregular heartbeat
• flushing of the skin
• headache
• lightheadedness
• numbness or tingling in the hands, feet, or face
• partial, or complete, impotence
• rapid weight gain
• swelling of the hands, feet, lower legs, or face

Normal results

Topical minoxidil is much more effective at treating baldness that occurs on the top, or crown, of the head than it is at causing hair growth on other parts of the head. Minoxidil does not work for everyone and there is no predictor, in early 2001, of whether or not it will be effective in any particular person. Clinical tests on the effectiveness of topical minoxidil in men with baldness on the top of the head showed that 48% of men who had used minoxidil for one year reported moderate to dense re-growth of hair within the treated area. Thirty-six percent reported minimal re-growth. While 16% reported no re-growth. Similar percentages have been reported in women.

In both men and women, hair re-growth generally does not begin until the medicine has been used for at least four months. The first signs that minoxidil may be effective in a particular person usually occur after approximately 90 days of treatment, when the patient notices that he or she is losing (shedding) much less hair than prior to beginning treatment.

When new growth begins, the first hairs may be soft and barely visible. For some patients, this is the extent to the effectiveness of this medication. For others, this down-like hair develops into hair of the same color and thickness as the other hairs on their heads.

Minoxidil is a treatment for hair loss, it is not a cure. Once a patient stops taking minoxidil, he or she will most likely lose all of the re-grown hair within 90 days of stopping the medication and no further hair growth will occur.

Resources

Periodicals

Bowser, Andrew. "Treatments Abound for Female Hair Loss." Dermatology Times June 1999.

Scow, Dean Thomas. "Medical Treatments for Balding in Men." American Family Physician April 15, 1999.

Organizations

American Academy of Dermatology. 930 N. Meacham Road, PO Box 4014, Schaumburg, IL 60168-4014. (847) 330-0230. Fax: 847-330-0050. http://www.aad.org/.

American Hair Loss Council. 30 Grassy Plain Road, Bethel, CT 06801. (888) 873-9719. http://www.ahlc.org/.

Key terms

Androgenetic alopecia — Hair loss that develops into baldness and affects both men and women.

Hypertension — Persistently high arterial blood pressure.

Scalp — That part of the head that is usually covered with hair.

Topical drug — Drug or medication applied to a specific area of the skin and affecting only the area to which it is applied.

Vasodilation — The increase in the diameter of a blood vessel resulting from relaxation of smooth muscle within the wall of the vessel. Vasodilation activates the blood flow.

Vasodilators — Drugs or substances that cause vasodilation.

minoxidil

 [mi-noks´ĭ-dil]

a potent, long-acting vasodilator, acting primarily on arterioles; administered orally as an antihypertensive agent and topically in treatment of androgenetic alopecia.

minoxidil

Apo-Gain (CA), Gen-Minoxidil (CA), Loniten (UK) (CA), Minox (CA), Regaine (UK), Rogaine, Rogaine Extra Strength

Pharmacologic class: Peripheral vasodilator (direct-acting)

Therapeutic class: Antihypertensive, hair growth stimulant

Pregnancy risk category C

FDA Box Warning

• Drug may cause serious adverse effects (such as pericardial effusion occasionally progressing to tamponade) and may exacerbate angina pectoris. Reserve it for hypertensive patients who respond inadequately to maximum therapeutic doses of diuretic and two other antihypertensives.

• Give under close supervision, usually concurrently with therapeutic doses of beta blocker to prevent tachycardia and increased myocardial workload. Usually, drug also must be given with diuretic to prevent serious fluid accumulation. Patients with malignant hypertension and those already receiving guanethidine should be hospitalized when therapy begins so they can be monitored to avoid too rapid, or large orthostatic, blood pressure decreases.

Action

Reduces blood pressure by relaxing vascular smooth muscle, causing vasodilation. Action in hair growth stimulation unclear; vasodilatory action may enhance microcirculation around hair follicles.

Availability

Tablets: 2.5 mg, 10 mg

Topical solution: 2%, 5%

Indications and dosages

➣ Severe symptomatic hypertension; hypertension associated with end-organ damage

Adults and children ages 12 and older: 5 mg/day as a single dose, increased carefully q 3 days. Usual range is 10 to 40 mg/day in single or divided doses. For rapid blood pressure control with careful monitoring, dosage may be adjusted q 6 hr. Maximum dosage is 100 mg/day.

Children younger than age 12: 0.2 mg/kg/day P.O. as a single dose. May increase in increments of 50% to 100% until blood pressure control is optimal. Usual range is 0.25 to 1 mg/kg/day; maximum recommended dosage is 50 mg/day.

➣ Male-pattern baldness; diffuse hair loss or thinning in women; adjunct to hair transplantation

Adults: Apply 1 ml of 2% or 5% topical solution to affected area b.i.d. for 4 months or longer.

➣ Alopecia areata

Adults: Apply 1 ml of 2% or 5% topical solution to scalp b.i.d.

Contraindications

• Hypersensitivity to drug or its components

• Dissecting aortic aneurysm

• Pheochromocytoma

Precautions

Use cautiously in:

• recent MI, malignant hypertension, heart failure, angina pectoris, severe renal impairment

• concurrent guanethidine therapy

• pregnant or breastfeeding patients.

Administration

• Give oral form with meals to decrease GI upset.

☞ If patient is also receiving guanethidine, discontinue that drug 1 to 3 days before starting minoxidil, to avoid severe orthostatic hypotension.

• Know that oral form is usually given with a beta-adrenergic blocker or diuretic to control hypertension.

Adverse reactions

CV: ECG changes (such as T-wave changes), tachycardia, angina, pericardial effusion, cardiac tamponade, heart failure

GI: nausea, vomiting

Respiratory: pulmonary edema

Skin: hypertrichosis

Other: weight gain, edema

Interactions

Drug-drug. Antihypertensives, nitrates: additive hypotension

Guanethidine: severe orthostatic hypotension

Nonsteroidal anti-inflammatory drugs: decreased minoxidil efficacy

Drug-diagnostic tests. Alkaline phosphatase, blood urea nitrogen, creatinine, plasma renin activity, sodium: increased levels

Hematocrit, hemoglobin, red blood cells: decreased levels

Patient monitoring

• Monitor vital signs and ECG.

• Assess daily weight and fluid intake and output.

☞ Monitor cardiovascular status carefully. Stay alert for signs and symptoms of heart failure.

• Watch for hypertrichosis.

• Know that hematologic and renal values usually return to pretreatment levels with continued therapy.

Patient teaching

• Instruct patient to take oral form with meals to decrease GI upset.

• Advise patient to weigh himself daily and report sudden gains.

• Tell patient taking oral form that drug may darken, lengthen, and thicken body hair. Tell him to shave or use depilatory to reduce unwanted hair growth. Reassure him that unwanted growth will disappear 1 to 6 months after he stops taking drug.

☞ Instruct patient to immediately report difficulty breathing (especially when lying down) or pain in chest, arm, or shoulder.

• Teach patient how to use topical form. Urge him to read package insert carefully.

• Caution patient not to use topical form on other body parts and not to let it contact mucous membranes.

• Tell patient using topical form that new scalp hair will be soft and barely visible. Caution him to use only 1 ml twice daily, regardless of amount of balding. Remind him not to stop using drug suddenly, because new hair growth will be lost.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

minoxidil

(mə-nŏk′sĭ-dĭl′)

n.

A vasodilator, C₉H₁₅N₅O, administered orally for the treatment of severe hypertension and used topically to promote the regrowth of hair in male and female pattern baldness.

minoxidil

Rogaine^® Hairology An agent first used as vasodilator and potassium channel opener in Pts with severe HTN, now used for androgenetic alopecia, alopecia areata, congenital hypotrichosis, loose anagen syndrome Adverse effects Sodium & water retention, pericardial effusion, hypertrichosis, hirsutism. See Hair, Hair replacement. Cf Terminal hair.

minoxidil

A VASODILATOR drug used in the treatment of high blood pressure (HYPERTENSION). Used externally on the scalp, the drug has a somewhat exaggerated reputation as a hair-restorer and must be used continuously if any advantage gained is to be retained. A brand name is Loniten and, for external use to restore hair, Regaine or Rogaine.

Patient discussion about minoxidil

Q. Does retinoin combined with minoxidil an effective treatment for hair loss? I'm looking into using a formula that improves the growth of hair with the retinoin like HairMD. Is it really effective or just a another baseless claim?

A. hair loss can also be traced to nutrition deficiency like omegas and such
you can google and search for food to nourish hair