Dogs are natural hosts for heartworms, a parasite that can cause extensive health issues and even death in dogs. With that said, most dog owners are aware that their pet should be on heartworm prevention medication. In the case that your dog is infected with heartworm disease, early treatment is important and drastically raises your dog’s chance of survival. Even if your dog is on preventative heartworm medication, it is still important to recognize the signs of heartworm disease, so you can seek treatment as soon as possible, in the unlikely event that your pet gets heartworms.
Ever noticed your furry friend looking more tired than usual? Wondering if heartworms could be the culprit behind your dog’s excessive napping? You’re not alone. As a dog owner myself, I’ve spent countless hours researching this very question, and what I’ve discovered might surprise you.
Heartworm disease isn’t just a scary diagnosis – it can dramatically affect your pup’s energy levels and sleep patterns. Let’s dive into the relationship between heartworms and canine sleepiness, so you can better protect your four-legged family member.
What Exactly Are Heartworms?
Before we tackle the sleepiness question let’s get clear on what we’re dealing with. Heartworm disease is caused by a parasitic worm called Dirofilaria immitis. These nasty little creatures are transmitted through mosquito bites and can grow up to a foot long inside your dog’s body! They primarily target the heart lungs, and blood vessels, causing serious damage over time.
The American Heartworm Society considers this a severe and potentially fatal disease that’s widespread throughout the United States And yes, while heartworms can infect many mammals, it’s particularly heartbreaking when they affect our beloved pets
Does Heartworm Disease Make Dogs Sleepy?
The short answer: Absolutely.
Lethargy and increased sleepiness are among the most common symptoms of heartworm disease in dogs. But why exactly does this happen?
Why Heartworm-Infected Dogs Get Sleepy
When heartworms invade your dog’s body, they don’t just sit there doing nothing. They actively:
- Cause inflammation in the lungs and surrounding blood vessels
- Reduce blood flow to vital organs
- Decrease oxygen circulation throughout the body
- Force the heart to work harder to pump blood
All these factors contribute to your dog feeling exhausted, even after minimal activity. It’s like asking your pup to run a marathon while breathing through a straw – no wonder they’re tired!
7 Key Heartworm Symptoms to Watch For (Including Sleepiness)
Lethargy isn’t the only sign that your dog might have heartworms. Here are the top symptoms you should never ignore:
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Excessive sleepiness and lethargy: Your once-energetic pup now seems tired all the time and avoids physical activity. This happens because of poor heart function and inadequate blood oxygenation.
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Exercise intolerance: Does your dog get winded after a short walk? Dogs with heartworms often can’t handle even moderate exercise because their lungs aren’t exchanging oxygen efficiently.
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Persistent dry cough: A soft, dry cough that worsens after activity is a classic heartworm symptom. This happens as worms multiply in the lungs and surrounding blood vessels.
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Difficult or rapid breathing: As worms collect in the lungs and blood vessels, your dog might struggle to breathe normally. Fluid buildup in the lungs makes it harder to oxygenate blood.
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Weight loss: When your dog doesn’t feel like moving, even to eat or drink, weight loss follows. This can happen rapidly and may lead to muscle wasting.
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Swollen belly: In advanced heartworm disease, fluid can accumulate in the abdomen (a condition called ascites), making your dog’s belly appear swollen.
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Collapse: In severe cases, mature heartworms can block blood flow completely, causing sudden collapse. This is known as caval syndrome and can be fatal within days if not treated.
The Progression of Heartworm Disease and Sleepiness
Heartworm disease doesn’t happen overnight. It progresses through stages, with sleepiness becoming more pronounced as the disease advances:
Early Stage
In the early stages, many dogs show no symptoms at all! In fact, about 32% of dogs diagnosed with heartworms are asymptomatic when first diagnosed. This is why annual testing is so crucial – you can’t rely on symptoms alone.
Middle Stage
As the disease progresses, you’ll start noticing:
- Mild coughing
- Reluctance to exercise
- Fatigue after moderate activity
- Some weight loss
Advanced Stage
In late-stage heartworm disease, symptoms become severe:
- Extreme lethargy
- Persistent coughing
- Labored breathing
- Significant weight loss
- Protruding ribs and chest
- Fluid-filled belly
- Potential collapse
Is It the Heartworm Disease or the Medication Making My Dog Sleepy?
Here’s where it gets interesting – both the disease AND the medication can cause sleepiness in dogs!
Heartworm Medication and Sleepiness
Some pet owners notice their dogs seem more tired after taking heartworm preventative medication. While not listed as a common side effect, anecdotal evidence suggests some dogs may experience drowsiness after taking heartworm preventatives.
Possible reasons for medication-related sleepiness include:
- Individual sensitivity to active ingredients like ivermectin or milbemycin
- Interactions with other medications
- Dosage considerations
- Timing of administration
If you suspect your dog’s heartworm medication is causing excessive sleepiness, try these tips:
- Give the medication at night before bedtime
- Ensure correct dosage (consult your vet!)
- Monitor sleep patterns after administration
- Provide mental stimulation to counteract drowsiness
- Maintain regular exercise
- Adjust feeding schedule around medication time
Remember: The sleepiness from medication is typically mild and temporary, while disease-related lethargy is more severe and persistent.
The Importance of Prevention vs. Treatment
I can’t stress this enough: preventing heartworm disease is MUCH easier than treating it. Once your dog has heartworms, the treatment is expensive, risky, and often causes additional side effects (including more lethargy during recovery).
Prevention options include:
- Monthly oral tablets (like NexGard Plus or Interceptor Plus)
- Topical treatments
- Injectable medications (administered by your vet)
The American Heartworm Society recommends year-round prevention for dogs in all 50 states, along with annual testing.
When to Call Your Vet About Your Sleepy Dog
Not all sleepiness means heartworm disease, but certain red flags warrant immediate veterinary attention:
- Sudden collapse or fainting
- Extreme lethargy combined with coughing
- Rapid or difficult breathing
- Visible weight loss or muscle wasting
- Bloated abdomen
- Refusal to eat or drink
Your vet can perform a quick heartworm test during your visit and determine if heartworms are causing your dog’s symptoms.
Real Talk: My Experience with Heartworm and Sleepy Dogs
As someone who’s volunteered at animal shelters for years, I’ve seen firsthand how heartworm disease affects dogs. One rescue pup I fostered, Max, went from being unable to walk around the block to running in the dog park after successful heartworm treatment.
But I won’t sugarcoat it – the road to recovery was tough. Max was even MORE sleepy during treatment than before. That’s because killing the adult worms can temporarily worsen symptoms as the dead worms break down in the bloodstream.
FAQ: Your Burning Questions About Heartworms and Sleepiness
How long does heartworm-related sleepiness last?
Without treatment, it progressively worsens. With treatment, expect increased lethargy during the recovery period (2-3 months), with gradual improvement as the worms die off.
Can heartworm preventatives make my dog sleepy?
Yes, some dogs experience drowsiness as a side effect of heartworm medication. This typically lasts from a few hours up to a day after administration.
Is it normal for my dog to sleep more after taking heartworm medicine?
Mild increased sleepiness can be normal, but excessive or prolonged lethargy should be reported to your veterinarian.
What’s the difference between normal tiredness and heartworm-related lethargy?
Normal tiredness resolves with rest. Heartworm-related lethargy persists regardless of rest and typically worsens with any physical activity.
The Bottom Line: Protecting Your Dog from Heartworm-Related Sleepiness
The connection between heartworms and sleepiness in dogs is clear – both the disease itself and sometimes the medications used to prevent or treat it can cause your dog to be more tired than usual.
Your best defense is:
- Year-round heartworm prevention
- Annual heartworm testing
- Prompt veterinary care if you notice symptoms
- Following your vet’s dosing instructions carefully
Remember, that slight drowsiness from preventative medication is a small price to pay compared to the serious, life-threatening fatigue that comes with actual heartworm disease.
Have you noticed changes in your dog’s energy levels? Do they seem unusually sleepy? Don’t wait to find out if heartworms are to blame – schedule that vet appointment today. Your furry friend is counting on you!
Diagnosing Heartworms in Dogs
During routine vet exams, we will recommend a heartworm test, which requires a small blood sample that detects the existence of heartworm proteins. If your dog tests positive for heartworms, we will recommend further testing to determine the course of treatment.
Warning Symptoms of Heartworms in Dogs
Heartworm disease in dogs is known as a silent killer, because it can take months before your dog shows symptoms. In the early stages of infection, most dogs show little to no symptoms at all, and the more the disease progresses, the more likely apparent symptoms will develop. Pay attention to these warning signs of heartworms in dogs, and take your pet to the vet if these symptoms persist.
- A dry unproductive cough. Once heartworms make their way into the lungs and begin reproducing in the lungs and surrounding veins, your dog will begin exhibiting a dry cough, typically after exercising. In some cases, these coughing fits might end in fainting, even after light exercise.
- Inactivity or laziness. Pay attention to your dog’s energy levels. If your pet seems more tired than usual, doesn’t want to go outside, or partake in physical activity, there is a good chance that your pet is sick. Dogs with heartworm infections will feel weaker, and will find it harder to remain active, even in low-energy activities.
- Weight loss and loss of appetite. In more advanced stages of heartworm infections, your dog will find it hard to complete normal physical tasks like eating. If you notice weight loss and a lack appetite in your dog, then you should take him to the vet immediately to rule out heartworms and other illnesses.
- Shallow and rapid breathing. When worms inhabit your dog’s lungs and the surrounding veins, respiratory problems will also occur. Along with coughing, the areas around the blood vessels in the lungs will begin to retain fluid, making it harder for your dog to receive oxygen, resulting in shallow, more rapid breaths.
- Distended chest. A swollen, bulged, or distended chest is typically a symptom of an adult heartworm infection. Usually this symptom is caused by weight loss, anorexia, and fluid buildup.
- Allergic reactions. While symptoms of allergic reactions are more common in cats with heartworms, dogs may also sometimes exhibit asthmatic symptoms similar to an allergic reaction in response to heartworm infection.
- Collapsing or fainting. Once a large population of heartworms enter the heart and causes a blockage of blood flow, known as caval or vena cava syndrome, fainting will occur. Collapsing usually correlates with shock and red blood cell destructions. At this point, the disease has progressed to a level where death can occur within days.
Heartworms can also cause nosebleeds, pneumonia, high blood pressure, seizures, blindness, and excessive sleeping. When heartworms reach places other than the heart and lungs, like the brain and eyes, dogs will experience seizures and blindness. However, these symptoms are rare for heartworms, and could be a sign of another condition.
As heartworm disease progresses, the treatments required becomes more invasive. This is why it is important to be aware of your dog’s normal behavior, so more subtle symptoms like inactivity doesn’t get disregarded.