Montelukast

BRAND NAMES:

Singulair  -Montelukast is a medication that prevents and treats the symptoms of asthma and allergies. It decreases inflammation in your airways. This makes it easier to breathe.

Available doses are 10 mg tablets

5 mg and 4 mg chewable tablets

4 mg oral granules 

MECHANISM OF ACTION:

As a leukotriene receptor antagonist, montelukast binds to the CysL T type 1 receptor with high affinity and selectivity. This suppresses all physiological actions of CysL Ts at the receptor, including LTC4, LTD4, and LTE4, which may aggravate allergic rhinitis or asthma. 

PHARMACOKINETICS:

Absorption: Montelukast absorbs fast after oral treatment. After administering a 10 mg film-coated tablet to fasting adults, the mean peak montelukast plasma concentration is reached in 3 to 4 hours. The typical oral bioavailability is 64%. A regular breakfast meal has little effect on oral bioavailability or C max in the morning.

Distribution: Montelukast's steady-state distribution volume ranges from 8 to 11 liters.

Metabolism: Montelukast is primarily metabolized in the liver. At clinically relevant doses, CYP2C8 appears to be crucial in the metabolism of montelukast.

Excretion: Montelukast and its metabolites are nearly eliminated in the bile and feces.

PHARMACODYNAMICS:

It can elicit bronchodilation as quickly as two hours after oral intake. This action can also enhance the bronchodilation generated by the concurrent administration of a beta-agonist. Therapeutic studies on people 15 years of age and older demonstrated that doses of montelukast greater than 10 mg per day provide no further therapeutic benefit.

DOSAGE AND ADMINISTRATION:

Montelukast is available as singular and generic montelukast in the following dosage forms taken by mouth.

4 mg chewable tablets

5 mg chewable tablets

4 mg oral granules

10 mg oral tablets

Montelukast is typically taken once each evening, with or without food. Take a single dose at least 2 hours before activity, and don't retake it for at least 24 hours. Swallow the standard tablet whole along with a glass of water. Do not change your dose or discontinue your asthma medication without consulting your doctor first.

DRUG INTERACTIONS:

Some medications may interfere with montelukast's effectiveness. Drug interactions with montelukast include epilepsy medications.- Phenobarbital or phenytoin 

• Tuberculosis: Rifampicin and other diseases 

• High cholesterol- Gemfibrozil 

• Nonsteroidal anti-inflammatory medications (aspirin or ibuprofen) 

CONTRAINDICATIONS:

Montelukast is not recommended for patients with a history of hypersensitivity to the medicine or its components. Patients who have phenylketonuria should exercise caution when using phenylalanine-containing formulations.

SIDE EFFECTS:

Mild side effects of montelukast oral tablets can include

•  Upper respiratory infections

•  Fever

•  Headache

•  Sore throat

•  Cough

•  Abdominal pain & Diarrhea

•  Ear infection

•  Runny nose

•  Sinusitis

•  Joint pain

Serious side effects and their symptoms can include

•   Increased level of Eosinophils- which can cause severe vasculitis. This is also known as Churg-Strauss syndrome.

•  Thrombocytopenia – which usually only causes symptoms in severe cases. Symptoms can include:

•  Severe rash or swelling, such as Stevens-Johnson syndrome.

•  Allergic reaction

•  Serious behavior or mood changes, including suicidal thoughts or behaviors

•  Sleep problems

•  Liver issues.

OVERDOSE:

In the event of a montelukast overdose, traditional supportive therapies such as gastric lavage, activated carbon adsorption, clinical monitoring, and, if necessary, supportive therapy can be used. There is no treatment for montelukast overdosage. Furthermore, no data exist on the efficacy of hemodialysis and peritoneal dialysis for eliminating montelukast from the body. 

• Stomach pain

• Sleepiness

• Thirst

• Headache

• Vomiting

• Restlessness or agitation

TOXICITY:

Montelukast does not have any known carcinogenic or mutagenic effects. Furthermore, there have been no reports of reproductive impairment or teratogenic effects with this chemical. Renal failure and mild-to-moderate hepatic impairment do not require dose adjustments.

STORAGE:

Maintain at 68° F to 77° F (20° C to 25° C).