HEADWAY

Minoxidil

Presentation

Headway Topical Solution is a clear, colourless to slightly yellow or orange-pink solution with an ethanolic odour. Headway Topical Solution is composed of minoxidil at a concentration of 20mg per mL, or 50mg per mL.

Uses

Actions

When applied topically, minoxidil has been shown to stimulate hair growth in individuals with alopecia androgenetica (male pattern baldness). The onset of hair growth stimulation occurs approximately after four or more months of use and is variable among patients. Upon discontinuation of minoxidil, new hair growth stops and restoration of pretreatment appearance is expected within three to four months. The exact mechanism of action of minoxidil in the treatment of alopecia androgenetica is not known.

Topical application showed no systemic effects related to absorption of minoxidil when tested in controlled clinical trials in normotensive and untreated hypertensive patients.

Pharmacokinetics

Following topical application minoxidil is poorly absorbed from normal intact skin, with an average of 1.4% (range 0.3 - 4.5%) of the total applied dose ultimately reaching the systemic circulation. This compares to essentially complete absorption from the gastrointestinal tract following oral administration of minoxidil tablets. Therefore a 1ml dose of minoxidil 2%, delivering 20mg minoxidil to the skin, would result in absorption of approximately 0.280mg minoxidil. The effects of concomitant dermal diseases or occlusion on absorption are unknown.

Serum minoxidil levels resulting from topical administration of minoxidil are governed by the percutaneous absorption rate. Following cessation of topical dosing of minoxidil, approximately 95% of systemically absorbed minoxidil is eliminated within four days. The metabolic biotransformation of minoxidil absorbed following topical application has not been fully determined.

Orally administered minoxidil is metabolised predominately by conjugation with glucuronic acid at the N-oxide position in the pyrimidine ring but also by conversion to more polar products. Known metabolites exert much less pharmacologic effect than minoxidil itself. Minoxidil does not bind to plasma proteins and its renal clearance corresponds to the glomerular filtration rate. Minoxidil does not cross the blood brain barrier. Minoxidil and its metabolites are hemodialyzable, and are excreted principally in the urine.

Indications

Headway Topical Solution is indicated for the treatment of alopecia androgenetica (male and female pattern baldness) and the stabilisation of hair loss.

Dosage and Administration

For external use only. Use Headway only as directed. Do not apply Headway to any other area of the body. A total dose of 1mL Headway should be applied twice per day to the scalp, beginning at the centre of the affected area. This dose should be used regardless of the size of the affected area. The total daily dose should not exceed 2ml. The method of application varies according to the disposable applicator used. After applying Headway wash hands thoroughly.

Apply Headway when the hair and scalp are thoroughly dry. Clinical experience with Headway Topical Solution indicates that twice daily application for four to eight months or longer may be required before evidence of hair growth stimulation can be expected. Onset and degree may be variable among patients.

Relapse to pretreatment appearance following discontinuance of medication has been reported to occur within three to four months.

Contraindications

Headway Topical Solution is contraindicated in those patients with a history of hypersensitivity to minoxidil, or any of the other ingredients in the formulations.

Warnings and Precautions

Patients being considered for Headway therapy should have a history and physical examination taken. The patient should have a healthy, normal scalp.

Although extensive clinical trials with minoxidil have not revealed evidence that enough minoxidil is absorbed to cause systemic effects, some absorption of minoxidil from the skin does occur and the potential exists for systemic effects such as salt water retention, generalized and local oedema, pericardial effusion, pericarditis, tamponade, tachycardia, angina, or potentiation of the orthostatic hypotension produced by peripheral vasodilators. Patients with a history of underlying heart diseases should be made aware that Headway may aggravate these conditions. Patients should be observed periodically for any suggestion of systemic effects of minoxidil. In the event of systemic side effects discontinue administration of the drug. If necessary, fluid retention and oedema can be managed with diuretic treatment. Tachycardia and angina can be controlled by administration of beta-adrenergic blocking drugs or other sympathetic nervous system suppressants. Patients should discontinue use of Headway and contact their physician in the event of severe dermatological reactions.

Pregnancy and Nursing

The effects of Headway Topical Solution in pregnancy are unknown. Systemically absorbed minoxidil is secreted in human milk. Headway should not be used by pregnant or nursing women.

Paediatric Use

Safety and effectiveness of Headway Topical Solution in patients under 18 years of age have not been established.

Use in the Elderly

Safety and effectiveness of Headway Topical Solution in patients over 65 years of age have not been established. Headway Topical Solution will cause burning and irritation of the eye. In the event of accidental contact with sensitive surfaces (eye, abraded skin, mucous membranes), the area should be bathed with copious amounts of cool tap water.

Accidental ingestion of Headway could lead to serious adverse effects. Keep this and all medications out of the reach of children. Inhalation of the spray mist should be avoided.

The effects of Headway in patients with concomitant dermal diseases, or in those using topical corticoids or other dermatological preparations, are unknown.

Adverse Effects

The most frequently encountered adverse effects in clinical trials with minoxidil 2% was itching of the scalp (1.5% of patients).

Infrequently reported adverse effects included

irritant dermatitis (redness
scaling and burning)
non-specific allergic reactions
hives
allergic rhinitis
facial swelling
sensitivity
shortness of breath
headache
neuritis
dizziness
light-headedness
syncope
vertigo
oedema
chest pain
blood pressure changes
palpitations
pulse rate changes

Rarely reported adverse effects included

allergic contact dermatitis
folliculitis
alopecia (hair loss)
unwanted hypertrichosis
seborrhea

In a comparative trial between minoxidil 2% and minoxidil 5% dermatological events were more frequent with minoxidil 5%.

The events were of similar type and severity but the incidence was greater in the 5% group.

Interactions

There are currently no known drug interactions associated with the use of Headway. Although it has not been clinically demonstrated, there exists the possibility of potentiating orthostatic hypotension in patients concurrently taking guanethidine.

Overdosage

Accidental ingestion may produce systemic effects related to the vasodilatory action of minoxidil (5ml of Headway Topical Solution 2% contain 100mg minoxidil, the maximum recommended adult oral dose for treatment of hypertension).

Signs and symptoms of drug overdosage would most likely be cardiovascular effects associated with fluid retention, lowered blood pressure or tachycardia. Fluid retention can be managed with appropriate diuretic therapy. Tachycardia can be controlled by administration of a beta-adrenergic blocking agent. If encountered, symptomatic hypotension should be treated by intravenous administration or normal saline. Sympathomimetic medicines such as norepinephrine and epinephrine, should be avoided because of their excessive cardiac stimulating activity.

Pharmaceutical Precautions

Store between 15-30°C (59-86°F). For external use only.

Package Quantities

Headway Topical Solution 2% containing 20mg minoxidil per mL and 5% containing 50mg minoxidil per mL are available as 60ml of solution in a bottle.

Metered disposable applicators: pump spray and extended tip assemblies.

Further Information

Nil.