When your pet has a medical condition, your veterinarian might prescribe one or more medications intended to manage, treat or cure the problem. Although there are some veterinary-specific drugs, many of the drugs used in veterinary medicine are the same as those used in people.
Commonly used medication types
The list below contains the most commonly used types of medications in dogs and cats, but is by no means a complete list of all of the types of medications used in veterinary medicine.
Antibiotics: these are drugs that kill microbes, such as bacteria and yeast, and are used to treat infections. They don’t kill viruses, but they are sometimes prescribed to treat secondary bacterial infections that can occur when an animal is ill from a viral infection. Examples in dogs and cats include penicillin, trimethoprim-sulfa, cephalexin and enrofloxacin.
Non-steroidal anti-inflammatories: these common drugs reduce swelling, inflammation, pain and lameness. Examples include carprofen, deracoxib, firocoxib, and meloxicam.
Opioid pain relievers: these medications are generally derived from morphine and can be potent pain relievers. Examples include oxycodone, hydromorphone, butorphanol, meperidine and fentanyl. Most of these drugs are controlled substances because of their addictive potential.
Steroids: steroids have many different uses. They can be potent anti-inflammatories and are frequently used to reduce allergic and anaphylactic reactions. They are also used at high doses to suppress the immune system. Examples include prednisone, prednisolone and dexamethasone.
Antiparasitics: these products are intended to prevent, repel or kill internal or external parasites such as intestinal worms, intestinal protozoans (Giardia, etc.), heartworms, fleas and ticks.
Behavior-modifying drugs and sedatives: these drugs are used to quiet anxious pets or help in reducing anxiety associated with various behavioral issues in pets, prepare pets for anesthesia, and to reduce pet movement during delicate procedures. Examples include diazepam, xylazine, acepromazine and midazolam.
Hormones and other medications used to treat specific conditions: Examples include insulin used for diabetes treatment, methimazole or levothyroxine for abnormal thyroid hormone levels, and heart medications such as atenolol, digoxin, and pimobendan.
Chemotherapeutics: these drugs are used to treat tumors and cancer. Examples include cisplatin, vincristine, doxorubicin and cyclophosphamide.
Drugs act in very different ways, and sometimes these different mechanisms can result in one drug interfering with another drug in some way. In addition, the body’s method of eliminating one drug can affect another medication by changing its rate of elimination from the body.
- Two drugs might have an additive effect, where the result produced is more than expected. This could be beneficial, but it could also be harmful.
- One drug might speed up or slow down the body’s metabolism or elimination of another drug, which could result in toxicity, organ damage, or ineffective treatment.
- One drug might prevent another medication from being effective by interfering with how it acts in the body.
Always tell your veterinarian the medications, including any over-the-counter medications and supplements (including vitamins and any holistic or homeopathic products), that you are giving your pet. Write down how often, how much, and how you give them and share this list with your veterinarian.
Side effects and adverse reactions
In general, medication choices involve weighing the advantages of the medication (stopping infection, reducing pain, etc.) against the potential risks, and taking measures to reduce side effects as much as possible. These preventive measures vary with the medication but can include keeping the drug dose and frequency as low as possible (but still effective); giving the drug for the shortest time needed; and giving the medication on a full or empty stomach.
Weighing the advantages and risks is an important process your veterinarian does, in part because the very mechanisms that make drugs effective for treating conditions can also cause unwanted effects. For example, non-steroidal anti-inflammatory drugs (NSAIDs) reduce the production of prostaglandins, many of which increase inflammation, pain and swelling. However, there are “good” prostaglandins in our bodies (and our pet’s bodies) that actually help protect us; an example is Prostaglandin E, which helps prevent our stomach from developing ulcers. Taking a NSAID reduces pain, swelling and lameness after an injury, but long-term use of NSAIDs can lead to stomach problems because of their effect in reducing Prostaglandin E. In addition, long-term use of NSAIDs can negatively affect prostaglandins in the kidneys, resulting in changes in blood flow within the kidney that can lead to kidney damage. This is why it’s so important to read any information your veterinarian gives you about the product, and to call your veterinarian if you suspect adverse events from any drug your dog or cat is taking.
Some medications need to be given for prolonged periods of time or perhaps for the rest of your pet’s life. To monitor your pet’s health, make sure that the drug is still working as it should be, and reduce the risk of toxicity or other harmful effects, your pet may need to be tested periodically. This may include blood tests, urine tests, or other tests as determined by your veterinarian, and these tests may be required before your veterinarian will provide a refill or refill prescription. This is particularly important with drugs like insulin and thyroid medications, where over- or underdosing can be life-threatening. A more common example is heartworm medication – your pet should be regularly checked for heartworm infection because giving the preventive to a heartworm-positive pet will not treat the infection and could cause a harmful adverse reaction. Also, local, state and federal laws may require regular rechecks before refills are authorized.
What you can do to keep your pet safe
When the medication is prescribed
- Let your veterinarian know if your pet has had adverse reactions to any medications.
- Ask questions so you understand why this medication is being recommended for your pet and what alternatives there are, if any, to this medication.
- When and how should this drug be used?
- What is the purpose of this medication?
- What should I do if I miss a dose?
- Ask your veterinarian what you should look for as signs of problems, adverse reactions to the medication, or a worsening of your pet’s condition.
- If you observe any of these signs, contact your veterinarian immediately. Do not discontinue your pet’s medication unless you are instructed to do so by a veterinarian.
- If you get your pet’s prescription filled at a pharmacy, do not let the pharmacy change the prescription in any way including changing the dose or the drug that was prescribed, without first consulting the veterinarian who prescribed it. Drug dosages in humans can be vastly different from what’s appropriate for a dog or cat. Likewise, there can be large differences between dog and cat prescription needs.
When giving the drug
- Keep medication bottles out of reach of your pets and children.
- Do not give your pet any medications, including over-the-counter (OTC) products, without consulting your veterinarian.
- Some drugs will interact with other drugs, including OTC medications and supplements, so your veterinarian needs to know EVERYTHING you’re giving your pet.
- Always follow the label directions. If you have any questions about the medication, ask your veterinarian.
- Keep the medicines in the containers in which you received them, and store them at the temperature indicated by your veterinarian. Don’t transfer the contents to another bottle or vial.
- Because pets' medication can be similar or the same as your medications, store them separately to eliminate the error of taking your pet's medication or giving your pet your medication.
- If your pet is on more than one medication, be very careful to give each medication as prescribed and according to label directions. The dose for the same pet can be very different among drugs, and you don’t want to give your pet too much or too little of its medication because you mixed up the labels.
- Never use one pet’s medication for another pet unless you are instructed to do so by your veterinarian. Never use your dog’s medication in your cat, because drugs that may be safe in dogs may not be safe in cats.
- Contact your veterinarian if you miss a dose or if you give too much (overdose) of the drug. If an overdose occurs during a time when your veterinarian’s office is closed, contact an emergency service or the ASPCA Animal Poison Control Center at (888) 426-4435 (a fee may apply).
- Always finish your pet’s medication unless you are instructed otherwise by your veterinarian.
- Some medications, such as many steroids, should be tapered in dose and not stopped “cold turkey.” Follow the label and your veterinarian’s directions.
When you no longer need the medication
Properly dispose of expired and unused drugs.
- Even if you think your pet has become ill with the same problem you’ve previously treated with a medication, don’t decide on your own to give your pet the same medicine or leftover medicine because it can be harmful and can delay an accurate diagnosis of your pet’s current problem. Talk to your veterinarian first.