Metacam is an anti-inflammatory and painkiller so will help him to continue eating as ear infections are very painful Please weigh him daily and consider syringe feeding a liquidised pellet mush (or critical care) as this will be easier and less painful for him to chew atm.
Moving on to a general answer concerning antibiotics:
Baytril is the only licensed antibiotic for guinea pigs and so baytril is most often prescribed and widely referred to online.
Before the advent of cavy savvy vets, the internet and decent diagnostics/medications; any guinea pig taken to the vet because it was poorly just had baytril thrown at it and it either survived or didn't.
Because of its widespread use in piggies over the years, the bugs causing infections in piggies are developing resistance to baytril.
Some more progressive vets are opting for other (unlicensed) antibiotics to treat different infections in guinea pigs depending upon the site of the infection and what they think the possible bug is.
e.g.
Some vets are starting to prescribe azithromycin for deep seated abcesses/jaw infections/stubborn URI's....whilst others (including my vet) will prescribe doxycycline as a first line antibiotic for URI's in preference to baytril because of antibiotic resistance
The bottom line is that unless the vet takes a swab and cultures to identify the bug and its antibiotic resistance profile - they are just making an educated guess in their choice of antibiotic (and have no idea what the actual bug is)
For this reason, my vets and I will always opt for the expense of a swab/culture before deciding which abx to prescribe unless the piggie can;t wait. Over the last two years we have cultured different types of bugs - e.g. Streptococcus, Staphylococcus, Corynebacterium, Pseudomonas that have been shown to be e.g. resistant to just baytril.....to baytril and septrin......to azithormycin only.....to all antibiotics except gentamycin....and many different permutations and combinations in-between. I personally would rather spend £50 up front on cultures now, than have weeks of repeat consultations, trying different abx, all to no avail as the piggie gets weaker.
Septrin and head tilt
Septrin is probably the second most commonly used antibiotic for piggies - it has a good broad spectrum activity against a wide range of bugs and is often the preferred antibiotic for treating urine infections. Unlike baytril, it tastes better for the piggie and doesn;t tend to upset the guts so much. However I have not come across it being used overmuch for head-tilt/ear infections and may not necessarily be as effective against some very specific organisms that are known to be responible for causing head tilt/ear infections in piggies.
In a recent thread on the same subject of head tilt/er infections,
@furryfriends Excellent Adventure Sanctuary has given details of how marbocyl injections (a similar drug to baytril) was effective against an inner ear infection. From my own experience, I have had two head tilt piggies that had middle ear infections which, on taking swabs and culturing them to identify the organism, turned out to be a multi-drug-resistant Pseudomonas that was resistant to all antibitioics except gentamycin (which is very strong nephrotoxic antibotiic and also given by injection - but only prescribed as a last resort when justified by cultures). They were also prescribed gentamycin ear drops. A third piggie of mine with head tilt was found to have ear mites.- so was given doramectin injections to treat the mites...and ear drops to counteract any secondary infection and inflammation.
Yogi's head tilt:
Did the vet inspect his ears with the cone-shaped instrument called an otoscope? What did he see if anything?
Head tilt can be caused by a number of things:
a) a bacterial infection in the outer/middle ear - which is normally visible through an otoscope as pus
b) ear mites - also visible on examination with an otoscope if the vet knows what they are looking for
c) an inner ear infection (only visible on Xray)
d) a parasite that normally infects rabbits called E caniculi - not diagnosible
e) stroke (more common in older piggies) or
f) unknown neurological inflammation
It sounds to me as though your vet thinks it is a bacterial infection (that is the most commonest cause of head tilt) and has chosen an antibiotic (Septrin) they feel comfortable with. If after 3-4 days there is no improvement, then you will need to go back to the vet. You will need to monitor his weight/food intake and poops (frequency/size/shape) to ensure he is still eating sufficient food each day and support him with syringe feeding if not. If the vet found pus in the ear then I would suggest that, whilst it increases the vets fees, a culture and sensitivity test would in the long run ensure that Yogi gets the right abx/treatment.
If the vet found no evidence of ear mites or outer/middle ear infection - then perhaps a harder hitting abx given by injection wiuld be preferable or even considering treatment for the parasite E caniculi which would require panacure.
Your vet has opted for a reaosnable, logical diagnosis and treatment (albeit cautious) based upon their experience and information to hand. In all probability this will clear up Yogi's head tilt - but if it doesn't - you are least have some guidance on what to do next.
HTH
x
