Naphazoline

Naphazoline is an active ingredient for the treatment of rhinitis and conjunctivitis. It belongs to the group of alpha-sympathomimetics and has a vasoconstrictive effect. Naphazoline is used as a decongestant nasal spray or as eye drops and should only be used in the short term (maximum one week) due to its dependency potential. Naphazoline is often used in medicines as naphazoline nitrate or naphazoline hydrochloride. It is a white, crystalline (crystal-forming) powder and is only slightly soluble in water. Naphazoline takes effect within a few minutes. The effect can last for several hours.

Naphazoline works by binding to the alpha-1 adrenoreceptors in the blood vessels. This binding leads to the release of noradrenaline, which also binds to the same receptors. After binding, the blood vessels constrict (vasoconstriction). As a result, less blood enters the affected region and the mucous membrane in the nose becomes less swollen. In the eyes, the lower blood volume means that fewer inflammatory substances reach the affected region, which reduces inflammation in the eye.

However, as naphazoline also binds to the beta-adrenoreceptors in a weakened form, the vessels dilate (vasodilation) after the alpha-1 adrenoreceptors have ceased to act, thus reversing the effect. Naphazoline therefore only relieves the symptoms of rhinitis and conjunctivitis, but does not combat the cause.

In addition, the release of noradrenaline causes negative feedback, i.e. reduced production of noradrenaline, which can lead to drug-induced inflammation of the nasal mucosa (rhinitis medicamentosa) if the nasal spray is used for too long. This leads to dependence and the naphazoline would need to be used every few hours to combat the swelling.

Naphazoline is broken down by the liver, but the majority is excreted unchanged in the urine. The effect of naphazoline can last for 4-8 hours.

Always take naphazoline exactly as described in the package leaflet or as advised by your doctor.

The usual recommended dose for the treatment of conjunctivitis is one drop per eye 3 times a day from 6 years of age. From 3-6 years 1 drop per eye 2 times a day.

If single-dose packs are not used, the vials of eye drops should be used for a maximum of 4 weeks.

When using naphazoline in the form of eye drops, hands should be washed beforehand. The drops should be dripped into the lower eyelid, then the eye should be closed and finally light pressure should be applied to the inner corner of the eye for about 1 minute to prevent the active ingredient from running into the tear duct.

The recommended dose for colds is 3-4 drops per nostril 4 times a day from the age of 12. From 6-12 years 2-3 drops per nostril 3 times a day. The dropper should be rinsed with hot water after each use to prevent contamination.

When taking naphazoline in the form of nasal sprays or nasal drops, the nose should be cleaned with a tissue beforehand. When applying in the nostril, the other nostril should be gently pressed closed with a finger. You should refrain from blowing your nose for a few minutes after application.

The following side effects may occur:

Psychiatric disorders:

• Anxiety,
• insomnia,
• restlessness

Cardiac disorders:

• Pulse acceleration (tachycardia),
• increase in blood pressure,
• cardiac arrhythmia

General illnesses:

• Nausea,
• Headache,
• drowsiness,
• burning pain at the site of application,
• increased blood flow to the nose after 6 hours,
• blurred vision,
• conjunctival irritation,
• pupil dilation,
• ringing in the ears (tinnitus)

Interactions may occur if the following medicines are taken at the same time:

• Drugs for the treatment of depression (MAO inhibitors, tricyclic and tetracyclic antidepressants) - a blood pressure crisis may occur
• Narcotics (anaesthetics), medication to dilate the pupils and insulin (for diabetes) - can increase the effect on the heart
• Alcohol, sleeping pills, anti-anxiety medication and neuroleptics (for mental illnesses) - can have a dampening effect on the central nervous system
• Theophylline (for asthma) - can increase side effects
• with guanethidine and reserpine (for blood pressure therapy) - can lead to an increase in blood pressure
• trihexyphenidyl as well as adrenaline and noradrenaline - can increase the effect of naphazoline
• with medications for gout or rheumatism, phenytoin, anticoagulants, barbiturates, griseofulvin, corticosteroids, p-aminosalicylic acid and halogenated hydrocarbons - this can lead to a weakening of the effect of naphazoline
• with alpha and beta receptor blockers (against high blood pressure) - interactions may occur

Naphazolin must not be taken in the following cases:

• if you are allergic to naphazoline
• inflammation of the nasal mucosa (rhinitis sicca)
• in the case of glaucoma
• after operations on the pituitary gland
• after operations performed through the mouth or nose
• when taking MAO inhibitors (for depression)
• for keratoconjunctivitis
• for cardiovascular diseases
• for diseases of the thyroid gland
• for pheochomocytoma
• diabetes mellitus (diabetes)

Naphazoline may be taken from the age of 3. However, this age may vary depending on the place of use.

Naphazolin should NOT be used during pregnancy, as it is not known whether the active substance can harm the unborn child.

Naphazolin should NOT be used during breastfeeding , as it is not known whether the active substance passes into breast milk and can therefore trigger effects in the infant.