ACTION AND MECHANISM

- Nasal decongestant. Oxymetazoline is an imidazole derivative of clonidine with alpha-agonist activity. Its pharmacology is not fully established, but its topical vasoconstrictor effects appear to be due to binding to postsynaptic alpha-2 receptors, although some alpha-1 effects cannot be ruled out. After topical administration, it causes vasoconstriction of the mucosal capillaries, reducing blood flow and mucosal swelling, thus producing a decongestant effect on the nasal passages.

The decongestant effects of oxymetazoline are longer lasting than those of alpha-1 agonists, such as phenylephrine, although slower.

PATIENT ADVICE

- The nose must be cleaned before each application.

- Proper nasal and applicator hygiene is advisable.

- It is recommended not to exceed the recommended daily doses or use for more than three consecutive days to avoid rebound congestion.

- Treatment should be discontinued and a doctor consulted if symptoms persist, worsen, or if high fever, dizziness, insomnia, or nervousness appear.

- It is common to experience a sensation of itching or nasal discomfort after application, which disappears after several doses.

CONTRAINDICATIONS

- Hypersensitivity to any component of the medication.

ADVANCED AGE

Elderly patients are more susceptible to adverse reactions from oxymetazoline when administered at high doses, as it can be absorbed systemically through the nasal or gastrointestinal mucosa.

EFFECTS ON DRIVING

Oxymetazoline can cause sedation, substantially affecting the ability to drive and/or operate machinery. Patients should avoid operating dangerous machinery, including automobiles, until they are reasonably certain that the medication does not adversely affect them.

PREGNANCY

Animal safety: no animal studies have been conducted, although other sympathomimetic amines have resulted in teratogenic effects in some species.

Safety in humans: There are no adequate and well-controlled studies in humans, so it is unknown whether nasal application of oxymetazoline could lead to adverse effects, although the possibility of systemic absorption should be considered. Use of this medication is only acceptable when safer therapeutic alternatives are unavailable.

Effects on fertility: no specific studies have been conducted in humans.

PHARMACOKINETICS

- Absorption: Few pharmacokinetic studies have been conducted with oxymetazoline. It has been shown that this drug may be absorbed after nasal administration. Decongestant effects appear after 5-10 minutes, reaching their maximum after 6 hours. Its vasoconstrictor activity can last up to 12 hours.

- Elimination: Oxymetazoline is eliminated in the urine, with 30% of the dose appearing unchanged after 72 hours. Some elimination also occurs in the feces (10%). Its elimination half-life is 5-8 hours.

INDICATIONS

- Symptomatic treatment of local and temporary [NASAL CONGESTION], as in the case of [COMMON COLD] and [RHINITIS].

INTERACTIONS

No drug interactions have been described with oxymetazoline administered nasally, although this drug could be absorbed through the nasal mucosa or by ingestion. There is some controversy regarding the effects of alpha-2 vasoconstrictors, as systemically they appear to have a predominant affinity for presynaptic receptors, resulting in sympatholytic effects. Nevertheless, and due to the possibility that this drug may also act on other adrenergic receptors, caution is advised when administering it with drugs such as MAOIs or tricyclic antidepressants, antihypertensives such as diuretics, beta-blockers, methyldopa, or guanethidine, thyroid hormones, nervous system stimulants, nitrates, or digoxin.

LACTATION

Animal safety: no data available.

Safety in humans: It is unknown whether oxymetazoline is excreted in breast milk, and its potential effects on newborns are also unknown. Given the possibility of systemic absorption, and because young children are particularly sensitive to the adverse effects of sympathomimetic amines, it is recommended that breastfeeding be discontinued or that this medication be avoided.

CHILDREN

Safety and efficacy have not been evaluated in children under 6 years of age, therefore its use is not recommended. Adverse reactions such as sedation are more common in children, and these can be severe and require supportive treatment.

GUIDELINES FOR PROPER ADMINISTRATION

It is recommended to administer this medication in the morning and at night, avoiding treatments longer than 3 consecutive days to prevent rebound congestion, which is often interpreted by the patient as a lack of effects, leading to a new administration, with the risk of overdose.
Before each administration, it is necessary to clean the nasal passages.
Insert the valve of the container into the nostrils, holding it vertically. Activate the valve while simultaneously taking a deep breath to facilitate maximum penetration of the medication. Each press should be brief, just long enough to fully depress and then release.
Once the medication has been administered, the valve end should be cleaned with hot water, then dried with a clean cloth.
Nasal spray: If this is the first time you are using this product or if it has not been used for a while, you need to prime the spray. To do this, holding the container away from your body, press the spray down several times until a fine mist is released.

POSOLOGY

- Adults and children from 6 years old:

PRECAUTIONS

- Patients in whom sympathetic stimulation could worsen their conditions. Oxymetazoline administered nasally theoretically poses no risk to these patients, although systemic absorption cannot be ruled out. Even in the event of such absorption, the effects on presynaptic alpha-2 receptors would theoretically predominate, with the consequent sympatholytic effects. However, it cannot be ruled out that this drug also has affinity for other adrenergic receptors, both alpha-1 and beta receptors, so most authors recommend exercising extreme caution in cases of conditions such as diabetes, glaucoma, coronary insufficiency, ischemic heart disease, cardiac arrhythmia, hypertension, hyperthyroidism, pheochromocytoma, or benign prostatic hyperplasia.

- Rebound congestion. The administration of topical vasoconstrictors frequently leads to rebound congestion, which is often accompanied by the patient administering another dose. This can pose a risk of overdose, as well as exacerbating the congestion. It is recommended to gradually discontinue the administration of oxymetazoline in cases of rebound congestion, alternating doses in each nostril, until complete cessation.

ADVERSE REACTIONS

The adverse effects of this medication are usually local and mild. However, systemic absorption of this medication cannot be ruled out, with the appearance of systemic adverse effects, which may increase in intensity and severity at higher doses. The most frequent adverse effects are:

- Local effects: Sneezing, nasal irritation, itching, and burning sensations, nasal dryness, or rhinorrhea are common. Rebound nasal congestion is also frequent, especially with high doses or after prolonged use. In cases of overuse, rhinitis may develop, with the nasal mucosa becoming edematous and appearing reddish or pale gray. These signs usually disappear after one week of discontinuing the medication.

- Systemic effects: Absorption of oxymetazoline may result in dizziness, vertigo, nausea, vomiting, nervousness, palpitations, high blood pressure, reflex bradycardia, hyperhidrosis, or pallor. In children, it may cause drowsiness.

ADVERSE REACTIONS RELATED TO EXCIPIENTS

- Because it contains benzalkonium chloride, it may cause [NASAL IRRITATION] or [RHINITIS], especially with long-term use.

OVERDOSE

Symptoms: There is limited experience with oxymetazoline overdoses, as acute overdoses are uncommon due to the method of administration. In cases of accidental ingestion of other drugs such as naphazoline, central nervous system depression is common, with sedation, severe hypothermia, bradycardia, and in severe cases, coma. This type of overdose is especially serious in children. Headache, tremor, palpitations, nervousness, or excessive sweating may also occur. The LD50 is 10 mg in children 2 years of age and approximately 100 mg in adults.
Treatment: After ingestion, it is recommended to eliminate the drug by gastric lavage and administer activated charcoal every 4-6 hours. In early stages, emetics and saline laxatives may be administered. However, these measures do not appear to be very effective, as sedation develops rapidly.
Treatment should be symptomatic and supportive. Diazepam should be administered if seizures occur. Vasopressors should be avoided if the patient is hypotensive. Monitoring of cardiac function and vital signs is recommended.