Hi and welcome to the GERD forum.
Yes, antibiotics will affect you and cause GERD symptoms.....
And your other med does have some side effects as well....
Call your doctor at once if you have:
changes in your vision;
severe stomach pain, diarrhea that is watery or bloody;
fever, swollen glands, body aches, flu symptoms, weakness;
skin rash, pale skin, easy bruising or bleeding, severe tingling, numbness, pain, muscle weakness;
upper stomach pain (may spread to your back), loss of appetite, dark urine, jaundice (yellowing of the skin or eyes);
chest pain, irregular heart rhythm, feeling short of breath;
confusion, nausea and vomiting, swelling, rapid weight gain, little or no urinating;
new or worsening cough with fever, trouble breathing;
increased pressure inside the skull--severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes; or
severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Common doxycycline side effects may include:
nausea, vomiting, upset stomach;
skin rash or itching; or
vaginal itching or discharge.
Since you mentioned LPR and PND have you tried a med to help reduce it? a H2b may be helpful or an antihistamine....talk with your Dr to see what would best help you. Prilosec is a PPI which stops your body from producing the acids which we need to break down foods....plus being on antibiotics you have none of the good bacteria to help break down foods.
A good Probiotic is great to take...but you may need a prescription one...these need to be kept in the fridge.....and ask your Dr about a H2b instead of the PPI.
Good luck and keep us posted on your progress.
Antibiotics will do a job on your digestive process. They stop the stomachs parietal cells from producing strong acid (HCL), which is necessary to sterilize and convert the nutrients consumed. Proteins are broken down, by the peptic enzymes. The Peptic enzymes are most effective when the strength of the hydrochloric acid is at 1.2 to 2.1 pH. As the strength of the acid decreases, pepsin becomes less active, in the conversion process. At pH 5.0 the peptic enzymes are completely inactive. Antibiotics stop the parietal cell from producing strong acid, making the gastric juices neutral, or alkaline (pH 6.0 to 7.5). When this occurs there is minimal sterilization and no conversion of proteins. Many proteins are allergens and will caused allergic reactions, if they are not destroyed, by the action of the peptic enzymes and hydrochloric acid. Without sterilization and conversion, raw proteins and nutrients prematurely dump into the small bowel, causing allergic reactions. The lack of sufficiently strong acid, in the stomach will allow bacteria, and pathogens to enter the digestive tract. Antibiotics also destroy the good flora in the digestive tract. I would highly advise getting a pH diagnostic test to determine the condition of your digestive process. There is a lot of info, at www.digestiveblog.com, or www.phapsule.com.