Antibiotics And Their Side-Effects

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As we said in our previous article, Vets And Kennel Cough, if you take your sick dog to the vet’s, they will most likely prescribe antibiotics.

So let’s look at some of the more popular antibiotics they might give your dog.


First on the list is a range of combination drugs called sulfa/trimethoprim, and you may find these under brand names such as Bactrim Rx, Tribrissen Rx, Ditrim Rx, Sulfatrim Rx and SMZ-TMP.

Side-effects of trimethoprim-sulfa are apparently rare, but you need to be aware that there is a potential for some serious ones.

It’s also important to know that these side-effects (or syndromes, or contra-indications, as they’re also known) are called “idiosyncratic reactions”.

What this means, in plain English, is that “their occurrence has nothing to do with the amount given but instead are about an unpredictable individual’s sensitivity to any dose.”

In other words, your vet has absolutely no way of knowing whether what they prescribe will cause any of these side-effects or not – so administering them is a gamble, a gamble with your pet’s life.

So, here’s what you might find from using this range of antibiotics:

  • blood dyscrasias (which can lead to immune deficiency, a tendency towards bleeding, and other blood-related disorders)
  • dry eye (i.e. an inability to produce tears)
  • hemolytic anaemia
  • hepatitis (i.e. liver failure)
  • joint inflammation (a problem which particularly affects Dobermans)
  • skin rashes
  • sulfa bladder stones.


Next on our list is doxycycline, where the shopping list of side-effects is extensive:

  • bloody stools
  • blurred vision
  • diarrhea
  • difficulty breathing
  • difficulty swallowing
  • feeling tired
  • fever
  • headaches
  • heartburn
  • hives
  • indigestion
  • itching
  • liver damage
  • loss of appetite
  • nausea
  • photosensitivity (i.e. a skin reaction to sunlight)
  • rashes
  • severe stomach cramps
  • swelling in the mouth or throat
  • vision changes
  • vomiting
  • wheezing
  • and more.

While we’re on the subject of prescription drugs, let’s move on to some of the chemical-based cough suppressants that vets may also prescribe:


Hydrocodone is what’s known as a semi-synthetic opioid, and is usually compounded with other less-effective non-opioid drugs such as paracetamol (otherwise known as acetaminophen) or ibuprofen.

Again, the side-effects are similar to those we’ve already covered:

  • anxiety
  • bloody, black, or tarry stools
  • blurred vision
  • change in amount of urine
  • change in the amount of urine produced
  • chest pain
  • confusion
  • constipation
  • dark urine
  • depression
  • diarrhea
  • difficulty breathing
  • difficulty urinating or inability to urinate
  • dizziness
  • drowsiness
  • dry mouth, throat, or nose
  • excitability
  • fainting
  • fast or irregular heartbeat
  • fever, chills, or persistent sore throat
  • flushing
  • gas
  • hallucinations
  • headache
  • hearing change or loss
  • heartburn
  • hives
  • increased sweating
  • itching
  • loss of appetite
  • mental or mood changes
  • nausea
  • nervousness or anxiety
  • numbness of an arm or leg
  • one-sided weakness
  • rapid or pounding heartbeat
  • red, swollen, blistered, or peeling skin
  • redness of face
  • ringing in the ears
  • seizures
  • severe dizziness, lightheadedness, or headache
  • severe drowsiness
  • severe headache
  • severe or persistent stomach pain or nausea
  • severe vomiting
  • shortness of breath
  • slow or shallow breathing
  • speech changes
  • stiff neck
  • stomach pain
  • sudden or unexplained weight gain
  • swelling of hands, legs, or feet
  • swelling of the mouth, face, lips, or tongue
  • thickening or mucus in nose or throat
  • tightness in the chest
  • tremor
  • trouble sleeping
  • unusual bruising or bleeding
  • unusual joint or muscle pain
  • unusual tiredness or weakness
  • upset stomach
  • vision changes
  • vomiting
  • weakness
  • yellowing of the skin or eyes.


Butorphanol is another common cough suppressant that is also used as an analgesic, and being a chemical (it’s another synthetically-derived opioid), it too has a massive list of possible side-effects:

  • abnormal dreams
  • agitation
  • anorexia
  • anxiety
  • blurred vision
  • bronchitis
  • chest pain
  • confusion
  • constipation
  • cough
  • depression
  • dizziness
  • dry mouth
  • dysphoria
  • dyspnea
  • ear pain
  • edema
  • epistaxis
  • euphoria
  • floating feeling
  • hallucinations
  • headache
  • hives
  • hostility
  • hypertension
  • hypotension
  • impaired urination
  • insomnia
  • lethargy
  • nasal congestion
  • nasal irritation
  • nausea
  • nervousness
  • palpitations
  • paresthesia
  • pharyngitis
  • pruritus
  • rhinitis
  • sensation of heat
  • shallow breathing
  • sinus congestion
  • sinusitis
  • somnolence
  • stomach pain
  • sweating/clammy
  • syncope
  • tachycardia
  • tinnitus
  • tremor
  • unpleasant taste
  • upper respiratory infection
  • vasodilation
  • vomiting
  • withdrawal symptoms.

Now, as we’ve said elsewhere, your vet may tell you that the chances of any of these side-effects occurring are very low, but if it happens to be your dog that’s the one in a million, does that really matter?

Hopefully, we’ve demonstrated that trying to treat kennel cough with chemicals is a bad idea – some of these side-effects are identical to the very symptoms that the drugs are trying to treat (e.g. coughing), while others are even worse.

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So, are you ready to learn how to treat kennel cough safely, without any of these side-effects (and, by the way, it’s very effective and cheaper too)?

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3 Responses to “Antibiotics And Their Side-Effects”

  1. Todd says:

    Hi there! I have a 14 1/2 year old indoor cat named Ti. She is a Domestic long hair and is 21 pounds but has never been sick. I took her to the vet last Wednesday to get shaved as she had some matting. Two days later she started sneezing a lot. This progressed into problems breathing out her nose. I did A LOT of research on this and I am 99.9% sure that she has an upper respiratory infection. Maybe it’s just sever kennel cough. Anyway, she has had a rough day today trying to sleep and sounds terrible at times. I do not have ANY money now to take her to the vet. I don’t have ANY money now period for 5 days. Anyway, I bought Amoxicillin at a pet store yesterday and called the vet. I told them what I purchased. They told me to give her two 250 MG tablets a day but of course wanted me to bring her in and didn’t guarantee that would work and that she had to be examined. I understand that as we don’t really know what it is. Again I am pretty sure though. I have been trying to figure out for the last 24 hours how to get her to ingest these capsules. Getting her to swallow a pill in the past has been a chore (sedation for airplane rides). I emptied the capsule in her water and she wouldn’t drink it. About 8 hours ago I emptied one on her food and she ate a decent amount of it. She does not seem comfortable. She is breathing slow to normal but just sounds bad through her nose (some “coughing” for a short while). She is just trying to sleep I think but can’t. Anyway, I finally forced a pill down her throat about 3 hours ago with success. She didn’t seem well. Not gasping for air or breathing fast but definitely a cause for concern. I even called a 24 hour emergency animal hospital I was so concerned. Shortly after I talked with them and about an hour after I gave her the pill…she got up and drank some water and nibbled on some food. About 5 minutes later she must have sneezed (quickly and repeatedly with short breaks) about 50 times! I took that as a good sign. After that…she sounded MUCH better than she had just minutes before. She is still trying to sleep..but it seems like a struggle for her. Weezing through her nose and maybe 15 minutes of sleep and then may wake up and looks frustrated. Quiet at times for a bit and then the nasal stuff and rarely a cough. Again I have NO money right now and she has NEVER been sick. So to me this is serious but maybe it’s just a upper respiratory infection that is viral and needs a few more days to run it’s course. Again this is day 7/8 since she started just sneezing. In your opinion, how serious is her condition…and will the anti-biotic Amoxicillin work? I guess they can’t hurt (minus any possible side-effects). I am SO sorry for the long message! lol. I am concerned right now however. Feel free to email me at:

    Your answer would be greatly appreciated!

    -Todd in San Diego

  2. Todd says:

    I am sorry! Also, do you think your product will help her condition. I am certainly very intrigues by this and as a last resort want to take her to the vet/animal hospital. (Again no money to pay them yet anyway). I will borrow the money with EXPRESS shipping if I have to if you think I need your product. Thanks!

  3. Rae and Mark says:


    Thanks for your questions, and sorry for the delay in getting back to you.

    As you say, it does sound like a respiratory infection – kennel cough can last for several weeks sometimes, so that’s one possibility.

    She may also have developed some from of allergy, or, at least, an allergic reaction to something.

    It may be worth asking your vet if they gave her anything when you took in her to have her shaved – it wouldn’t be the first time that a vet had given an animal something without asking the owner first.

    Another factor, of course, is her age. At 14.5 years, she’s certainly no kitten any longer, and it may just be nature taking its course.

    As animals grow older, their immune systems begin to fail, and the more chemicals they’ve been exposed to during their life (e.g. vaccines, dewormers, prescription drugs), the worse this will be.

    Unfortunately, most modern commercial pet food is stuffed full of ingredients that are anywhere from unnecessary to dangerous and disgusting. And, yes, they are full of chemicals and allergens in many cases too.

    As for the Amoxicillin, then if it is a viral infection, it won’t do any good at all. And as you touch on, there are always potential side-effects with chemical-based medicines, which is why we stay clear of them. Amoxicillin isn’t as bad as some of the newer antibiotics, but you never know how a particular person or animal will react to these drugs.

    For us, the key to keeping our dogs healthy is to build up their immune system as much as we can, and this involves keeping chemicals away from them (i.e. we don’t vaccinate, we don’t give chemical-based dewormers and/or heartworm preventative drugs, and we make sure they don’t ingest household and/or garden chemicals) and feeding them a high-quality, chemical-free dog food.

    The only dog food we use with our dogs is Triumph dog food, and although we don’t have cats (the dogs wouldn’t appreciate that), we would certainly use Triumph cat food if we did have any.

    While the chemicals in vaccines, etc. are very bad, at least they’re only given these relatively infrequently, whereas they eat their food every single day, so any toxins, chemicals, etc. in that food are being ingested constantly.

    All of the chemicals that pets these days are exposed to (not least of which are, of course, vaccinations), are a leading cause of more and more pets developing cancers, and at an ever-younger age too.

    Finally, we appreciate your financial situation, but we have two recommendations for you.

    Firstly, the absolute minimum we would recommend is the Primalix KC, as this product was specifically developed to treat kennel cough, but it will be beneficial for other respiratory conditions too.

    Secondly, if you have the funds available, we would recommend both the Primalix KC, for the reasons given above, and another product called Primalix Immune Builder, as this will help to keep her immune system strong.

    We use the Daily Maintenance Kit with our dogs every day. This includes the Immune builder mentioned above and the Herbal Parasite Formula. We give them a single dose each day. These two products are safe for cats too and since they are usually very small in body weight the 2×4 oz bottles will last a long time.

    We hope this helps, and that whatever you decide to do, Ti gets better soon.

    Best wishes,

    Rae & Mark

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