Cetirizine for androgenetic hair loss: Why not just use the oral?

Topical vs Oral Cetirizine for Androgenetic Alopecia

I’ve selected this question below for this week’s question of the week. It allows us to review new research on topical cetirizine in male hair loss.

Question

I see that you’ve mentioned that topical cetirizine is being studied for treating various types of hair loss including androgenetic alopecia. I’m wondering why not just use oral cetirizine as it’s easy to find over the counter and really not that expensive.

Answer

Thank you for this question! Research studies into the use of ‘topical cetirizine’ are still in the early stages. The one thing that is clear is that topical cetirizine appears fairly safe so far. How well it works for treating hair loss issues is still open to some debate. In studies so far, topical cetirizine appears less effective than topical minoxidil.

The one thing that is clear is that topical cetirizine appears safer than oral cetirizine (ie Zyrtec, Reactine etc). Now whether topical cetirizine works any differently for treating hair loss compared to oral cetirizine for androgenetic has never been published.

I think it’s important to be aware that oral cetirizine is fairly safe but no, it’s not completely safe. It would be a mistake to assume that oral cetirizine is without side effects. There are about 100 side effects that are ‘theoretically’ possible with oral cetirizine. Fortunately, most side effects are mild and the long list of side effects is not that common. However, side effects do occur and are more likely with higher doses (20 and 30 mg) than lower doses (5 and 10 mg).

What are the side effects of Cetirizine?

You might want to review our handout for common side effects of cetirizine. it’s not a list of all possible side effects but it is a list of more common ones. Headaches and drowsiness are among the more commonly reported side effects but even these occur in less than 10 % of users. One must never operate machinery or drive when first starting this drug in case it makes the person drowsy. One must also be cautious of using alcohol and sedatives in general as these too can make users drowsy. The is normally a non drowsy (non sedating) antihistamine for most people.

Other side effects include Fatigue (6%), Dry mouth (5%), Dizziness (2%), Diarrhea (3), Malaise (4%), Bronchospasm (2-3%), Vomiting (3%), and Nosebleeds (4%).

Less than 1 % experience side effects such as: Stomach pain, Drowsiness, Angioedema, Fussiness, Hallucinations, Hypotension, Tremor and Tongue discoloration

At higher doses (especially the off label non approved 30 mg doses), these side effects may occur and other side effects may also occur including heart rhythm issues (arrhythmias).

Taken together, it would not correct to assume that oral cetirizine is 100 % safe. The proper way to think about oral cetirizine is that it is “quite safe for a very large proportion of people at 5-10 mg dosing.”

Drug interactions

The other thing we need to think about as we talk about oral cetirizine is drug interactions. There are many medications that can interact with oral cetirizine. So anyone using oral cetirizine needs to review their current medications with a pharmacist. These types of interactions are likely much less relevant with topical cetirizine.

Concentrating higher doses of cetirizine at the level of the hair follicle

What matters most in this discussion is how much cetirizine actually gets concentrated at the level of the hair follicle. A person can take 10 mg of cetirizine by mouth but how many mg or micrograms or nanograms actually get up there to the hair follicle? Probably some ….but that actual numbers are not known. With topical cetirizine, the hope is that higher amounts can be deposited right under the hair follicle where the benefits can take place. With seemingly good side effect profile, this warrants further study.

Conclusion

Studies on topical cetirizine are still in the early stages. Fortunately, the treatment appears quite safe and likely much safer than oral cetirizine. Whether topical is better than oral cetirizine … or not will need more studies. The hope is that use of topical cetirizine can concentrate a greater amount of cetirizine at the level of the hair follicle than oral cetirizine …with reduced chances of side effects.

For further review of the subject, please see the video by clicking on the link below.