Combination treatments

[zabfranklin]

Hi.
At the breastfeeding clinic where I work we receive referrals from community health clinics concerning breastfeeding and medications. The doctors use LactMed and a local database in order to decide if breastfeeding is ok, but they usually refer questions concerning combination treatments with CNS active medications: e.g Fluoxetine daily with occasional use of Prometazine (Lergigan) or Oxazepam (Oxascand).

The pediatricians find it very difficult to say yes to these combinations. I need some concrete info on how these combinations should be regarded. My questions are:
Do two CNS active medications always exarcebate each others effects?
If taking occasional dose of medicines such as Prometazine and Oxazepam, what constitutes acceptable length of treatment or number of tablets per week?
How does this relate to higher dosages of various medicines: eg will a higher dose of Fluoxetine lead to more risk with an occasional dose of other CNS active drugs?

Thanks for your help

[admin]

Zabfranklin:

My advice re combinations, is to review the side effect profile of each independently. IF, however, they both have similar side effects, such as somnolence, then you might want to be slightly more cautious. If you have 2-3 drugs, that all have the same potential side effect, then you might want to avoid breastfeeding with these combinations.

If however, they are dissimilar in effect, such as a beta blocker, and a SSRI, then no problem at all. Just watch for drug-drug interactions when they exacerbate one another, such as two sedatives, two diuretics, etc.

As for promethazine, we recommend caution. It is well known to produce neonatal apnea, and I generally recommend against its use in breastfeeding mothers. We have other drugs that are preferred.

As for dosing, I always become somewhat uncomfortable with a mother using higher than normal dosing. Once you go above the normal range, then the Relative Infant Dose is likely to be higher, particularly with drugs that already have significantly higher RIDs.

So, you always have to decide on the dose of the drug, its relative risk to the infant, and its Relative Infant Dose.

Tom Hale Ph.D.