doryx and retin-a

[vunja]

I have really bad acne and it's gotten to the point where my therapist feels that it's just adding fuel to my already low self esteem, so she told me to see a dermatologist. she even recommended one. so I went, and this is what I got. she prescribed:

doryx (doxycycline hyclate) 100 mg

retin-a (tretinoin) topical

okay. this is what I'm taking. more in-depth than my signature because I want to be sure that whoever might be able to help me has all the information. daily in the evening, I take:

prozac (fluoxetine) 20 mg

ativan (lorazepam) 1 mg

magnesium supplement

iron supplement

I don't know a lot about the magnesium or the iron. they were sort of a last ditch attempt to stop my restless legs syndrome and get my healthier. I've checked sites and drug interactions and that jazz and the stuff I'm taking now seems to work together pretty well, and the restless legs has stopped so I'm not changing anything.

this is what I'm worried about: my doctor didn't tell me anything about the meds. nothing. I got everything you see here from the prescription sheet. (she spent the whole time talking about my long eyelashes and paper clip earrings.) she wrote the prescription totally offhandedly, like it was something she does all the time and it didn't merit any thought at all. this seems bad enough to me. I didn't want to waste her time so I didn't ask her anything about the meds, figuring I could find some more stuff on the internet later.

I went to my favorite drug interactions site at drugdigest.org and I put in some stuff. since I'm not sure what kind of magnesium I'm taking, I just stuck all my options in and I figured I'll remember what kind it was if any red flags came up.

well, the red flags came up. it looks like certain kinds of magnesium clash with the doryx. is this something I should worry about? I told the doctor that I took magnesium and she didn't say anything about itm so I'm thinking maybe I'm just finding something that doesn't exist or doesn't matter, but. I'm still worried about it, especially since the doctor told me NOTHING about these meds. (I'm realizing that I need a new dermatologist who won't get preoccupied with my earrings.)

my second question is if anyone else has tried these, just personal experiences would be welcome. more info about them would be wonderful. I've googled them both and found out that doryx is for inhalational anthrax (wtf?) and so that worries me a little.

any help at all would be appreciated. thank you. <3

[Penny Century]

doxycycline is a very common anitbiotic for acne. it can work wonders, just stay out of the sun. way out of the sun.

don't take the magnesium or iron with the doxy. take it three hours before or two hours after you take the doxy. the magnesium and iron will bind with the doxy and prevent it from being absorbed.

i took doxy for 6 weeks for lyme disease, and in the process it cleared up some stubborn acne i had from a trial of lamictal. it should really help your skin.

[AirMarshall]

I don't see any major problems with this med combo.

Yes doxycycline has been used since at least the 1970's for acne. I believe retin-a became available in the early to mid 1980's. And, YES, the dermatologist rx these every day, so it doesn't take her great handwringing agonizing to consider them.

The retin-a is topical and should have little absorption into the body, hence no interaction.

- The main concerns are between the vitamins and the antibiotic. You need to take them (the vitamins vs doxy) at least 3 hours apart, best if you can get them on opposite schedules, i.e. 12 hours apart. The vitamins can bind with the doxycycline causing reduced availablity and effectiveness. If that were to happen the dermatologist might consider increasing the doxy dose or switch to another antibiotic.

Don't worry, be happy! Good luck with the treatment!

a.m.

Interatction list from http://www.drugs.com

You have searched for drug interactions between the following drugs: doxycycline hyclate, tretinoin topical, Prozac, Ativan, magnesium oxide, ferrous fumarate

Please note: only generic drug names are displayed.

Drug-Drug Interactions

doxycycline and magnesium oxide (moderate Drug-Drug)

Description:

ADJUST DOSING INTERVAL: Administration of a tetracycline with aluminum, calcium, or magnesium salts significantly decreases tetracycline serum concentrations. The proposed mechanism of action is chelation of tetracycline by the cation. Decreased AUC has also been reported with parenteral doxycycline and oral antacids.

MANAGEMENT:

The administration of tetracyclines and a preparation containing aluminum, magnesium, or calcium should be separated by two to three hours.

doxycycline and ferrous fumarate (moderate Drug-Drug)

Description:

GENERALLY AVOID:

The bioavailability of oral tetracyclines and iron salts may be significantly decreased during concurrent administration. Therapeutic failure may result. The proposed mechanism is chelation of tetracyclines by the iron cation, forming an insoluble complex that is poorly absorbed from the gastrointestinal tract. In ten healthy volunteers, simultaneous oral administration of ferrous sulfate 200 mg and single doses of various tetracyclines (200 mg to 500 mg) resulted in reductions in the serum levels of methacycline and doxycycline by 80% to 90%, oxytetracycline by 50% to 60%, and tetracycline by 40% to 50%. In another study, 300 mg of ferrous sulfate reduced the absorption of tetracycline by 81% and that of minocycline by 77%. Conversely, the absorption of iron has been shown to be decreased by up to 78% in healthy subjects and up to 65% in patients with iron depletion when ferrous sulfate 250 mg was administered with tetracycline 500 mg. Available data suggest that administration of iron 3 hours before or 2 hours after a tetracycline largely prevents the interaction with most tetracyclines except doxycycline. Due to extensive enterohepatic cycling, iron binding may occur with doxycycline even when it is given parenterally. It has also been shown that when iron is administered up to 11 hours after doxycycline, serum concentrations of doxycycline may still be reduced by 20% to 45%.

MANAGEMENT:

Coadministration of a tetracycline with any iron-containing product should be avoided if possible. Otherwise, patients should be advised to stagger the times of administration by at least three hours, although separating the doses may not prevent the interaction with doxycycline.

magnesium oxide and ferrous fumarate (moderate Drug-Drug)

Description:

ADJUST DOSING INTERVAL: The bioavailability of orally administered iron may be reduced by concomitant administration of an antacid or other agents with acid-neutralizing effects. The interaction has been suspected in some patients with diminished hematologic response to iron therapy. The exact mechanism is unknown but may involve reduced iron solubility due to increase in gastric pH or complexation of the iron. Based on existing data, sodium bicarbonate and calcium carbonate appear to have greater effects than antacids containing magnesium and aluminum hydroxide, which have been reported to have minimal to moderate effect on iron absorption. The interaction reportedly does not occur in the presence of ascorbic acid, which may competitively bind with iron and prevent the interference with iron absorption.

MANAGEMENT:

To minimize the potential for interaction, it may be appropriate to administer oral iron preparations at least two hours apart from antacids or other agents with acid-neutralizing effects.

lorazepam and magnesium oxide (minor Drug-Drug)

Description:

A number of studies have reported that antacids can delay the gastrointestinal absorption and reduce the peak plasma concentration (Cmax) of some benzodiazepines, including clorazepate, chlordiazepoxide and diazepam, although the overall extent of absorption is generally not affected. The exact mechanism of interaction is unknown but may involve delayed gastric emptying or cation binding of the benzodiazepine. As a result, benzodiazepine onset of action may be delayed and clinical effects diminished. However, one study reported a significant increase in diazepam absorption during coadministration with aluminum hydroxide, and there was a marginal increase in the onset of sedative effect. Aluminum hydroxide also increased the Cmax and systemic exposure (AUC) of triazolam in 11 dialysis patients such that their drug levels reached into the range observed for the matched controls. In contrast, another study by the same group of investigators found no significant effect of aluminum hydroxide on temazepam absorption or Cmax in 11 patients with end-stage renal disease. A multi-dose study also failed to find an effect of antacids on the steady-state levels of N-desmethyldiazepam, the active metabolite of clorazepate, although an acidic environment is thought to be necessary for the rapid conversion. Based on available data, the clinical significance of this interaction appears to be minor. As a precaution, patients may want to consider separating the administration times of benzodiazepines and antacids or oral medications that contain antacids (e.g., didanosine buffered tablets or pediatric oral solution) by 2 to 3 hours.

Drug-Food Interactions

ferrous fumarate (minor Drug-Food)

Description:

Food taken in conjunction with oral iron supplements may reduce the bioavailability of the iron. However, in many patients intolerable gastrointestinal side effects occur necessitating administration with food. Some studies suggest administration of iron with ascorbic acid may enhance bioavailability. Ideally, iron products should be taken on an empty stomach, but if this is not possible, administer with meals and monitor the patient more closely for a subtherapeutic effect.

[vunja]

doxycycline is a very common anitbiotic for acne. it can work wonders, just stay out of the sun. way out of the sun.

don't take the magnesium or iron with the doxy. take it three hours before or two hours after you take the doxy. the magnesium and iron will bind with the doxy and prevent it from being absorbed.

heh, I don't go in the sun anyway. but thanks, I'll keep that in mind.

okay, thanks. I'll remember that. I appreciate your reply and the help. <3 thank you. good experiences are nice, too, they give me hope.

Yes doxycycline has been used since at least the 1970's for acne. I believe retin-a became available in the early to mid 1980's. And, YES, the dermatologist rx these every day, so it doesn't take her great handwringing agonizing to consider them.

The retin-a is topical and should have little absorption into the body, hence no interaction.

- The main concerns are between the vitamins and the antibiotic. You need to take them (the vitamins vs doxy) at least 3 hours apart, best if you can get them on opposite schedules, i.e. 12 hours apart. The vitamins can bind with the doxycycline causing reduced availablity and effectiveness. If that were to happen the dermatologist might consider increasing the doxy dose or switch to another antibiotic.

Don't worry, be happy! Good luck with the treatment!

a.m.

okay. I suppose I'm a little too used to taking crazy meds, which should take longer to prescribe. makes sense, I guess. thanks.

okay, sounds good. thank you.

I appreciate both of your responses. note to self: stop freaking out.

thanks. <3

[herpie]

Retin-A sucks. I don't know how much enters the blood stream when used topically, but it's not completely negligible. For example, parents using topical steroids on babies are encouraged to be careful because they penetrate the skin and can put a baby at risk.

The problem is, Retin-A may cause or worsen depression, because it's (that's not a joke!) toxic to brain cells (neurons in hippocampus, to be precise). With topical use it may not be a huge risk, but it's a risk nevertheless.

[AirMarshall]

I don't often disagree with Herpie, but I'm going to take exception on this one. Especially about a topical skin medication which is a naturally occuring breakdown of vitamin A in the body!

I don't know how much enters the blood stream when used topically, but it's not completely negligible. For example, parents using topical steroids on babies are encouraged to be careful because they penetrate the skin and can put a baby at risk.

- Absorption? I find figures between 1 - 5% on intact skin. Users are cautioned not to apply it to broken or irritated skin.

- Comparing the toxicity of large amounts of steroids in babies is completely unfair. For one, the two drugs have NOTHING in common. Secondly is the danger with applying topicals to infants is based on the fact that their skin area to body volume is several times higher than in adults. Meaning that they recieve a proportionally higher dose for the same body part.

The problem is, Retin-A may cause or worsen depression, because it's (that's not a joke!) toxic to brain cells (neurons in hippocampus, to be precise). With topical use it may not be a huge risk, but it's a risk nevertheless.

- I am unable to delve into brain toxicities. However I will point out that retinoic acid is metabolized by the liver. It is present in the body naturally as a breakdown product of vitamin A.

Searching Pubmed I find little to suggest it as a significant danger. In fact I only found 5 references going back about 28 years.

- Last year in 2005, a review of all published studies found NO statistically significant relationship between use of retin a and either depression or suicide!

- A report from 2004 suggests that retin a may aid the brain in neuroplasticity or regrowth.

- Only one case report relating depression and retin a. The woman already had untreated depression, had chronic Hepatitis C (which affects the livers ability to clear retin a) and who had obtained the retin a cream from a friend without medical supervision. The woman reported that she used "large amounts" of the cream and that she continued to use it despite it burning her skin, and that she scratched and gouged her skin (which would allow much higher absorption). While it is possible that the retin a may have worsened her depression, there are a number of factors which make this a worst case scenario.

Overall there is little published reports suggesting retin a causes or worsens depression. Millions and millions of people have used this skin ointment for over 25 years. I suggest not getting spooked over this. Ask your dermatologist about her experiences.

a.m.

[herpie]

13-cis Retinoic acid (accutane) suppresses hippocampal cell survival in mice

Chronic Administration of 13-Cis-Retinoic Acid Increases Depression-Related Behavior in Mice.

FDA approves mandatory risk management program for isotretinoin. (no abstract, no full text)

Functional brain imaging alterations in acne patients treated with isotretinoin.

Affective psychosis following Accutane (isotretinoin) treatment.

Too much of a good thing: retinoic acid as an endogenous regulator of neural differentiation and exogenous teratogen.

13-cis-retinoic acid suppresses hippocampal cell division and hippocampal-dependent learning in mice

That's not a lot of evidence - and keep in mind that the last two articles are written by more or less the same team. But the risk with oral tretinoin may be real (though the evidence is rather equivocal). With topical - I just don't know, maybe the tiny amount of tretinoin that enters the blood stream can be beneficial.

As for retinoic acid necessary for neuron survival - no doubt, the question is, which isomers of RA are necessary and which are harmful and in what quantities. As far as I can understand, tretinoin is a 13-cis isomer of retinoic acid.

The only thing I can be sure of, is that with my MRI-confirmed hippocampal atrophy and pretty crappy hippocampus-dependent memory, I won't touch that stuff, ever. On the other hand, my acne is more tolerable to me than any further memory loss would be.

[AirMarshall]

Interesting about Accutane. It is a potent drug with significant side effects. Still they are different chemicals and taking large doses internally is far different than applying a topical med.

For comparison:

Accutane daily dosage for a 130lb person: medium 60mg; high: 120mg

Retin-A is available in a 20 gram gel tube, concentrations of 0.04% and 0.1%

Assuming that 1 gram per day of gell is applied, at the higher 5% absorption rate, total systemic dose is:

0.1% = 5mg

0.04% = 0.4mg2mg

So if taking Accutane, exposure is between 12 to 3,000 times higher than using Retin-A topical gel. And would 70 to 15,000 times higher if the gel absorption is only 1%.

Certainly Accutane should not be used casually, but I don't think we should raise panic flags over Retin-A, a topical gel used at much lower levels applied to the skin.

Respectfully, a.m. (nice work out you are giving me)

[herpie]

Indeed, sounds quite safe, assuming it's used properly (not on open sores, moderate quantites). I believe I'm overreacting, although (as I wrote above) I have a personal reason for that.

Hope it does make your acne go away

0.1% = 5mg

0.04% = 0.4mg

Uh... I don't seem to get that math...

0.04% = 2mg, in my opinion (not that math is really a matter of opinion )

[AirMarshall]

Oops. Thanks for correction. I pulled figure from wrong column.

If you have documented brain function tests, then I don't blame you for being cautious.

a.m.