Buto-Vent is a two-way bronchodilator, based on Mepifiline (mepyramine acetylinate). Mepifiline is a bronchodilator composed of the linkage of a xanthine (acetylinate or theophylline acetic acid) and an antihistamine H1 (mepyramine). The bronchodilator action is mainly due to the inhibition of phosphodiesterase mediated by the xanthine component. Mepyramine blocks the effects of histamine and therefore causes bronchodilation.


Mepifiline is absorbed from the gastrointestinal tract, presenting peak plasma concentrations 2-4 hours after administration.

It is metabolized at the liver level by sulfurization and glucuronization and is eliminated through faeces and urine, its elimination half-life being 3 or 3.5 hours.

Preclinical data show no special risk to humans based on conventional studies in safety pharmacology, repeated dose toxicity as after single administration. (Oral LD50 in rat = 2,840 mg / kg).


Buto-Vent is indicated for: treatment of bronchoconstriction in patients with acute and chronic bronchitis, bronchial asthma and its prophylaxis, emphysema and obstructive bronchopathies.


Hypersensitivity to the active substance or to any of the excipients.

In patients with liver dysfunction, bladder neck obstruction, symptomatic prostatic hypertrophy or urinary retention, and angle-closure glaucoma.

Buto-Vent syrup contains sorbitol; therefore, patients with hereditary fructose intolerance should not take it.

Special warnings and precautions for use

Avoid alcoholic beverages during the administration of Buto-Vent. Hypersensitivity to antihistamines: Patients who are sensitive to some antihistamines may be sensitive to others.

It is not recommended for use in newborns or premature infants, as this age group presents a greater sensitivity to anticholinergic side effects such as excitation of the Central Nervous System and a greater tendency to seizures.

There are reports of a possible association between the use of antihistamines in general during the last 2 weeks of pregnancy and an increased risk of retrolental fibroplasty in premature infants. The use of Buto-Vent is only accepted in the absence of safer therapeutic alternatives.

Although the amount of mepifilin excreted in breast milk is unknown, the presence of this drug in breast milk has been documented by qualitative testing. Also, antihistamines can inhibit lactation due to their anticholinergic effects. Due to the risk of adverse effects (irritability or excitement) in children in general, and particularly in infants and premature infants, it is recommended to suspend breastfeeding or avoid the administration of Buto-Vent.

Its administration is not recommended during pregnancy or lactation.


Buto-Vent Syrup

Mepifiline     25 mg

C.S.P excipients     5 ml


Buto-Vent Capsules

Mepifiline     150 mg

C.S.P excipients     1 cap.

Posology  and  administration


Administration route: Oral

The average dose of Buto-Vent is 8 mg per kg of body weight per day, the total dose divided into 4 doses. The maximum dose is 18 mg per kg of body weight per day, the total dose divided into 3 doses.

Children under 5 years: 1 to 2 teaspoons (5 ml) 4 times a day.

Children older than 5 years: 2 to 3 teaspoons (5 ml) 4 times a day.

Adults: As maintenance therapy, doses of 1 to 2 measures of 15 ml 4 times a day are usually sufficient, or 1 to 2 capsules every 8 hours.

In severe cases it is recommended to resort to injectable treatment.


Buto-Vent syrup: Box containing a bottle with 120 ml of syrup.

Buto-Vent capsules: Box containing 2 blisters with 10 capsules each.

Storage Recommendations

Store at a temperature below 30 °C.

Interaction with other medicinal products and other forms of interaction

Alcohol: Simultaneous intake with this medication may potentiate the effects of alcohol.

Medicines that produce depression on the Central Nervous System (CNS): the simultaneous use can potentiate the depressant effects on the Central Nervous System of these medicines or of antihistamines. The simultaneous use of maprotiline or tricyclic antidepressants can potentiate the anticholinergic effects of antihistamines.

Medicines with anticholinergic action: mepifilin can potentiate these effects.

Monoamine oxidase inhibitors (MAOIs): the simultaneous use of MAOIs with antihistamines can prolong and intensify the anticholinergic and CNS depressant effects of antihistamines; Simultaneous use is not recommended.

Interference with diagnostic tests: Skin tests using allergenic extracts: antihistamines can inhibit the skin response to histamine leading to false negative results; It is recommended to stop antihistamines at least 72 hours before starting the test.

Side Effects


Common: blurred vision, confusion, difficult urination, dizziness, dry mouth, tachycardia, ringing in the ears, rash, epigastric pain or discomfort.

Uncommon: blood dyscrasias, cardiac arrhythmias.

In elderly treated with antihistamines, dizziness, sedation, confusion and hypotension are more likely.


Sale by prescription. Keep out of reach of children.