Common Nausea, Vomiting, Skin rash, Allergic reaction.

Expert advice for Trimethoprim
Trimethoprim can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.
Before you take trimethoprim tablets or suspension, tell your doctor:

If you suffer from kidney problems.
If you have a deficiency (are low) in folic acid.
If you are at greater risk of high levels of potassium in your blood (hyperkalemia), e.g. the elderly or those on higher doses.
If you are also taking repaglinide (medicine for treating diabetes).

Do not take trimethoprim if you are pregnant or breast-feeding. You may be required to undergo regular blood tests if you need long-term treatment or are prone to anaemia.
Consult your doctor immediately if you experience any of these adverse effects.

fever, chills, body aches, flu symptoms, sores in your mouth and throat.
pale skin, easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple/red pinpoint spots under your skin.
signs of high pottasium levels (slow heart rate, weak pulse, muscle weakness, tingly feeling).
severe headache with muscle cramps, confusion, weakness, loss of coordination, feeling unsteady, and weak or shallow breathing.

Q. Is Bactrim DS a sulfa drug/an antibiotic/ a strong antibiotic/ good for sinus infection/ good for UTI/ good for tooth infection/strep throat/ MSRA?
Bactrim DS is a strong antibiotic combination containing trimethoprim and sulfonamide antibiotic. It is good for treating urinary and respiratory tract infections including treating sinus and strep throat as per doctor's recommendation. It is not a drug of choice for treating and tooth infections

Q. Is Bactrim DS safe/ makes you feel sleepy/ cause fungal infections?
Bactrim DS is safe at recommended doses and duration. It is not sure but it may make you feel sleepy (drowsiness). It does not cause fungal infections

Q. What is Ciplin DS/ suspension Septra DS used for/ Septra DS affect birth control?
Ciplin DS/suspension, Septra DS are a combination of trimethoprim and sulfamethoxazole and is used for treating a variety of bacterial infections. Antibiotics such as Septra DS can decrease the effectiveness of birth control pills and thereby affect birth control. Consult your doctor before its use

Q. Does Trimethoprim make you feel sick/ make you drowsy/ cause constipation?
Trimethoprim may make you feel sick (nausea). It is not sure but it may cause drowsiness and constipation.