From the Guidelines
It is generally safe to take Singulair (montelukast) and Zyrtec (cetirizine) together, as they work in different ways to treat allergic conditions, with Singulair blocking inflammatory chemicals and Zyrtec blocking histamine. These medications are often prescribed together, especially for people with both allergic rhinitis and asthma, as they complement each other's actions 1. Singulair is typically taken once daily as a 10mg tablet for adults, while Zyrtec is usually taken as a 10mg tablet or liquid once daily.
When considering the use of these medications together, it's essential to note that cetirizine, the active ingredient in Zyrtec, may be associated with sedative properties, including mild drowsiness, especially at higher doses 1. However, this effect is generally milder than that observed with first-generation antihistamines.
Some key points to consider when taking Singulair and Zyrtec together include:
- Following the recommended dosages: 10mg once daily for Singulair and 10mg once daily for Zyrtec
- Being aware of potential side effects, such as headache, fatigue, or dry mouth
- Monitoring for any unusual symptoms, such as increased drowsiness, and contacting a healthcare provider if concerns arise
- Establishing a routine by taking both medications at the same time of day
Overall, the combination of Singulair and Zyrtec can be an effective treatment strategy for managing allergic conditions, and with proper guidance from a healthcare provider, patients can safely use these medications together to achieve optimal symptom relief 1.
From the FDA Drug Label
Montelukast at a dose of 10 mg once daily dosed to pharmacokinetic steady state: did not cause clinically significant changes in the kinetics of a single intravenous dose of theophylline (predominantly a cytochrome P450 1A2 substrate) did not change the pharmacokinetic profile of warfarin (primarily a substrate of CYP 2C9, 3A4 and 1A2) or influence the effect of a single 30-mg oral dose of warfarin on prothrombin time or the INR (International Normalized Ratio).
The FDA drug label does not answer the question.
From the Research
Safety of Taking Singulair and Zyrtec Together
- There are studies that suggest taking Singulair (montelukast) and Zyrtec (cetirizine) together can be safe and effective for treating allergic rhinitis and asthma symptoms 2, 3, 4, 5.
- Montelukast is an antiasthmatic agent that has a high affinity for the CysLT1 receptor and is not influenced by human serum protein 6.
- The combination of montelukast and an antihistamine, such as levocetirizine (similar to cetirizine), has been shown to be more effective than monotherapy in treating persistent allergic rhinitis 3, 4, 5.
- A study found that the combination of montelukast and levocetirizine significantly improved nasal symptoms in patients with persistent allergic rhinitis, and the improvement increased over time 4.
- A meta-analysis demonstrated the efficacy of montelukast combined with levocetirizine in treating nasal symptoms in allergic rhinitis with asthma, and indicated that the combination is more effective than monotherapy and has good safety 5.
Efficacy of Combination Therapy
- The combination of montelukast and an antihistamine has been shown to be effective in treating allergic rhinitis and asthma symptoms, with improved nasal symptoms and quality of life 2, 3, 4, 5.
- Montelukast alone has been shown to improve asthmatic symptoms and respiratory indices, and inhibit airway inflammation and exercise-induced bronchoconstriction 6.
- The addition of an antihistamine to montelukast has been shown to have added benefits, and in some cases, is reported to be equivalent to intranasal corticosteroids 2.