My pup had the same symptoms as yours but he had Parvovirus i think there are so many things a puppy can pick up.

Tell your vet about this. It's possible that it was a wrong diagnosis.

contact a vet immediately

One of the things I believe to be most insidious is that it seems likely to me, from my own research, that Giardia is one of those nasty creatures whereby the dog or cat can REINFECT themselves, because this is an infectious condition. I've put together some links for you to read over, if you will. I don't know how much your Vet discussed this with you, but the more you know about it the better armed you will be to not only choose your treatments but also stay safe yourself...humans CAN CATCH THIS TOO. This condition is NOT an easy cure situation...You may want to also look into speaking with a vet who is knowledgeable and open minded to Holistic and Homeopathic Remedies, I have seen it clear up with Homeopathics, but you need someone who knows what they are doing! Best of luck to you and your big, beautiful boy! You really do want to get this cleared up ASAP as it can cause additional health challenges over the long haul, especially since he is assuredly still growing and maturing. http://www.peteducation.com/article.cfm?articleid=739 Remember, Giardia of dogs may infect people, so good, personal hygiene should be used by adults when cleaning kennels or picking up the yard, and by children who may play with pets or in potentially contaminated areas. How do Giardia reproduce and how are they transmitted? Giardia multiply by dividing. A dog becomes infected by eating the cyst form of the parasite. In the small intestine, the cyst opens and releases an active form called a trophozoite. These have flagella, hair-like structures that whip back and forth allowing them to move around. They attach to the intestinal wall and reproduce by dividing in two. After an unknown number of divisions, at some stage, in an unknown location, this form develops a wall around itself (encysts) and is passed in the feces. The Giardia in the feces can contaminate the environment and water and infect other animals and people. If we find Giardia, how do we treat it? Here we go again; treatment is controversial too. There is a question about when to treat. If Giardia is found in a dog without symptoms should we treat the animal? Since we should not know if G. canis can infect man, we often err on the side of caution and treat an asymptomatic infected animal to prevent possible transmission to people. If we highly suspect infection with Giardia, but can not find the organism, should we treat anyway? This is often done. Because it is often difficult to detect Giardia in the feces of dogs with diarrhea, if there are no other obvious causes of diarrhea (e.g.; the dog did not get into the garbage several nights ago) we often treat the animal for giardiasis. There are several treatments for giardiasis, although some of them have not been FDA-approved for that use in dogs. Fenbendazole is an antiparasitic drug that kills some intestinal worms and can help control giardia. It may be used alone or with metronidazole. Metronidazole can kill some types of bacteria that could cause diarrhea. So if the diarrhea was caused by bacteria, and not Giardia, the bacteria can be killed and the symptoms eliminated. Unfortunately, metronidazole has some drawbacks. It has been found to be only 60-70% effective in eliminating Giardia from infected dogs, and probably is not 100% effective in cats, either. It can be toxic to the liver in some animals. It is suspected of being a teratogen (an agent that causes physical defects in the developing embryo), so it should not be used in pregnant animals. Finally, it has a very bitter taste and many animals resent taking it – especially cats. Quinacrine hydrochloride has been used in the past, but is not very effective and can cause side effects such as lethargy, vomiting, anorexia, and fever. But now we come to yet another unknown. It is possible these treatments only remove the cysts from the feces but do not kill all the Giardia in the intestine. This means even though the fecal exams after treatment may be negative, the organism is still present in the intestine. This is especially true of the older treatments. So treated animals could still be a source of infection for others. http://www.vetinfo4dogs.com/dgiardia.html http://www.thepetcenter.com/exa/gia.html