Diseases, Disorders information

Methenamine is Mandelamine. This has been around forever. It liberates formaldehyde in an acid urine.

Anthelmintics. Pyrantel pamoate and mebendazole, Anamenth and Vermox all are useful in most of the common infestations that we have. I would point out that that the pyrantel pamoate is available over the counter. You don’t have to write a prescription for that if you don’t want to.

Albendazole is a newer antiparasitic drug that has been marketed. This is Albenda. Again, it is useful in pinworm and most of the common infections. It is suggested that it be given with a fatty meal to enhance absorption. In animal studies, though, it has been hepatotoxic and it’s also suggested that it may be teratogenic. So I think probably most clinicians are sticking with the old standbys that we’ve had around forever.

Metronidazole is Flagyl. We’ve mentioned the use of this particular product in pseudomembranous colitis. It’s useful in intestinal amebiasis, vaginal infections. It is the drug of choice for Giardiasis. It also can be used for GI strains of bacteroides or anaerobes. In fact, Flagyl or metronidazole, in many circles, is considered the drug of choice for anaerobe prophylaxis and treatment because it is fairly nontoxic and it is less expensive than things like cefoxitin or clindamycin.

Its toxicities include nausea, headache, a metallic taste in the mouth and a disulfiram or Antabuse-like reaction with alcohol. There have been claims in the past that this drug is carcinogenic. It is not. There is no proven history of any tumor formation in humans with this product. It probably should be avoided during the first trimester of pregnancy but after that it is probably a safe drug to use.
Canadian Pharmacy Antibiotics
Pediculicides and scabicides, again, are a controversial area. Lindane or Kwell is being roundly criticized as it well should be. This was used for many years as the routine pediculicide of choice. People tended to think that you drowned it with Kwell rather than just using it sparingly. It’s now been shown that this fairly readily absorbed, can get into the brain and may have neurotoxic effects if it’s overused.

Antifungal antibiotics. There are just buckets of these. I would comment on a couple of things. First of all, amphotericin B is a very toxic drug when you have to give it IV. It’s nephrotoxic. It causes hypokalemia. It causes a syndrome we call “shake and bake” which is chills or shakes and fever.

There are newer products available that are lipid complexes. Abelcet and Amphotec and AmBisome. These will cut down on the nephrotoxic reactions and will cut down on the intolerance of the drug but they are more than 20 times more expensive than amphotericin B. So when you can use amphotericin B continue to use it. For those patients who have renal impairment or are intolerant of amphotericin B, these may very well be useful.

Flucytosine may be useful in some fungal infections. However, there are others that have largely replaced it. Ketoconazole may be useful for mucocutaneous candidiasis and some other infections. There are a whole bunch of drug interactions with these products and they can cause disulfiram-like reactions.

Fluconazole or Diflucan is often preferable to Ketoconazole when that might be used. It can be used single dose for vaginal candidiasis. It is the drug of choice for coccidioidal mycosis. It can be used for cryptococcosis. It does have some hepatotoxic reactions. It can be teratogenic so you would want to be careful about using that drug during pregnancy.

Itraconazole or Sporanox can be useful in things like blasto- and histoplasmosis. It’s the drug of choice for that indication. It may be useful in aspergillosis and nail infections, mucosal candidiasis.

There are two different forms of this product out there. One is a capsule and one is a suspension. Be aware that the capsule should be given with meals but the suspension should be given between meals.

Terbinafine or Lamisil is another product that has been marketed. It may be useful in treating nail infections. The usual treatment course is six to twelve weeks. It costs less than itraconazole so it might be a reasonable substitute. The other drugs have been around forever.

Miconazole IV is not usually a preferred drug but I put it on for completeness and no doubt you’ve seen more nystatin in your life than you’d care to ever see.

Sulfas. Major uses. These can be used in urinary tract infections. They can be used in combination therapy for otitis media. Be aware that allergic reactions and blood dyscrasias are problems. These drugs can cause literally any kind of skin rash known to mankind.

Gantrisin or sulfisoxazole has been used in otitis media prophylaxis. I presume you’ve had your pediatrics lecture by now?

Cotrimoxazole. This is Bactrim or Septra. This is used for things like otitis media and pneumocystis carinii prophylaxis and treatment. The problems with these drugs are mainly related to sulfa although trimethoprim can cause some bone marrow suppression.

It’s for that reason that some patients who are immunosuppressed may occasionally be put on Bactrim or Septra three times a week, Monday, Tuesday, Wednesday or something like that. Basically that is to suppress pneumocystis. Pneumocystis is a fairly slow growing organism. It only requires occasional exposure to the drug to be able to suppress it or to keep it from growing. So if we gave it every day in somebody with bone marrow suppression, we might be further suppressing the bone marrow with the trimethoprim and that’s the reasoning for that. It’s not that somebody has made a mistake.

Cefotetan or Cefotan is another product very similar to cefoxitin in its uses. It is used less often, once a day or twice a day, so this may be preferable in some circles if you want to use a cephalosporin for anaerobes.

Cefmetazole can cause some reactions. Bleeding, disulfiram or Antabuse-like reactions with alcohol. We really don’t see a unique use for this product so we tend not to talk very much about it.

Similarly, cefonicid is marketed as Monocid. It has more activity against H. flu but it is less active against Gram positives. So, again, we don’t see a really unique place where this drug should be used and it’s one that I don’t see a particular amount of use for.

Now, if I need to stick a stick in a hornet’s nest and shake it up, this is the one drug that I will potentially create controversy with and that’s cefaclor or Ceclor. This drug is way overused. It is a very palatable drug. Children will take it. But it is not that effective. It has been shown that tissue levels may be lower than with other oral cephalosporins. Serum sickness is possible with repeat use, much more so than with any of the other cephalosporins and actually the cost of this drug, even though it is now available in generic form, is only about $5 for a prescription less than some of the new second and third generation cephalosporins. So this really is a drug that possibly you could forget about and there are plenty of other good drugs available that are going to cause a lot fewer calls in the middle of the night because of treatment failures or adverse reactions.

Cefprozil is Cefzil. This is a product that is given once or twice a day as an oral tablet or suspension. It can be used for otitis media and soft tissue infections although this is not a drug of first choice usually. It certainly is a reasonable alternative particularly in patients who have trouble tolerating some of the drugs that we will mention to you later.

Cefuroxime is marketed as a parenteral product – Zinacef – and also as an oral tablet or suspension as Ceftin. While it used to be used in meningitis, it is no longer recommended for use because it is not as effective as the third generation agents. It does have good activity against many of the common infecting organisms that cause soft tissue infections and pneumonias. It is a good empiric therapy, for example, in a pediatric pneumonia because it covers most of the common infecting organisms unless you think there is a meningitis present.

The problem with cefuroxime is that it is very bitter. The suspension needs to be given with food. Regardless, it tastes bad. Kids under three don’t seem to mind that terribly and that’s a prime age group for using this drug, for example, in acute otitis media and I will mention another drug that is very similar to this in a few minutes. But it is less expensive than the third generation cephalosporins so it may have some cost advantage unless you’re worried about meningitis.

Third generation cephalosporins generally have an increased Gram negative spectrum with decreased Gram positive activity generally. They are considered third generation based on a broader Gram negative spectrum. Some people think of these as being third generation because of anti-Pseudomonal activity but frankly none of the oral third or fourth generation agents have Pseudomonas coverage.

CSF levels with many of these parenteral products are adequate to treat meningitis. In fact, several of these drugs are considered drugs of choice for meningitis now. Be aware though that these drugs have poor coverage of Listeria and poor coverage of Enterococcus so you can get overgrowth of these particular organisms. For example, in a neonatal intensive care unit you may see ampicillin being added to Claforan in a child with sepsis to cover the possibility of Listeria.

Cefotaxime is Claforan. This is probably the most useful of the third generation cephalosporin parenteral products. It is given parenterally usually every six hours. It is a drug of choice for neonatal sepsis and meningitis and is a drug for meningitis in general in pediatrics. It is useful in gonorrhea especially in young children and in CNS Lyme disease. It has minimal effects on bowel flora and that fact is going to come back as we talk about several of the other products in terms of being a unique advantage for this product.

Ceftizoxime is Ceftizox. This particular product is like Claforan or cefotaxime but it is given every eight hours. However, we don’t have a great deal of experience with this in children and the literature generally has not adapted this instead of cefotaxime. Cefotaxime continues to be the preferred drug.

Ceftriaxone is Rocephin. This particular product is just as good as Claforan against meningitis. The advantage here is that it is given once a day. The problem here, though, is that this drug has a much greater effect on suppressing bowel flora than does cefotaxime. It’s for that reason that we would prefer to use cefotaxime or Claforan for IV therapy in institutionalized patients and switch to Rocephin or ceftriaxone when we switch to IM therapy or for home therapy. There is no sense in inducing pseudomembranous colitis or other severe diarrheas with a drug when we have an alternative drug that is only a little more expensive that is available and that is the reasoning behind the use of that. However, that said, this is a very good drug for treating gonorrhea. It’s a good drug for treating serious Lyme disease and it is especially useful for IM therapy.

Cephalosporins. There are now four generations of cephalosporins. The third and fourth generation cephalosporin differences are fairly minor and we will treat those as a group. First generation cephalosporins and second generation cephalosporins do not cross the blood-brain barrier in adequate quantities to be able to use those for any CNS infections. So none of these would be recommended for treating a meningitis, for example. The first generation agents generally cover Gram positives including Staph aureus to about the same extent as the penicillinase resistant penicillins. So these are good drugs to use instead of the drugs like oxacillin.

The cephalosporins, as a group, may be useful in penicillin allergic patients but the general rule of thumb should be if they had an anaphylactoid reaction to penicillin, avoid cephalosporins if you can. If they have a rash with penicillin, there is probably about a 5% incidence of cross-reactivity but that’s not too much higher than the 3% background rate of rash that you are going to get anyway. So most clinicians would suggest that it is safe to use these provided you counsel the patient about stopping the drug and contacting you if a rash develops.

A major use for the first and second generation agents is in surgical prophylaxis, particularly the first generation agents. Gram negative spectrum with the first generation agents is quite spotty. We do not suggest that they be used for Gram negative infections. As I mentioned earlier, these are very useful and probably actually are the preferred drugs for treating non-methicillin resistant Staph aureus infections where a liquid is needed.

Cefazolin is Kefzol. You’ll notice I don’t have cephalothin or Keflin on this. Cephalothin had to be given every six hours. It caused a lot of IM pain. Cefazolin is given every eight hours. It causes less IM pain and really in most hospitals has replaced cephalothin and therefore that’s the only one I have listed here. So this would be the parenteral drug that usually would be used. Cephapirin or Cefadyl is another drug that is very much like cefazolin and has similar uses.

For the oral cephalosporins, actually these drugs may be quite useful in Staph aureus infections particularly as the liquids. Liquid Keflex of cephalexin. One of the products is bubble gum flavored. It’s quite well tolerated by children. It’s not terribly expensive so this may be a preferred product.
Antibiotics
Our experience here has been that cephalexin is the product we prefer in preadolescent children when we are trying to treat a Staph infection or we want to use an oral first generation cephalosporin. For adolescents and adults, we often would use cefadroxil. Cefadroxil does come in a liquid dosage form and is given less often so that should improve compliance. But our experience with trying to use cefadroxil in younger children, we found that we were having more treatment failures than when we had been using cephalexin so we switched back. So, in general, I would suggest the use of cephalexin or Keflex in younger children and in adolescents and adults use cefadroxil.