What is the specific relative contraindication of each of these drugs?
Septrin contains trimethoprim and sulfamethoxazole [1 part trimethoprim to 5 parts sulfamethoxazole]. Betablockers and Verapamil can cause complete heart block and should not be prescribed without specialist supervision.
NSAIDs can precipitate asthma.
Haloperidol can cause extra pyramidal side effects i.e. parkonsonian symptoms, dystonia, akathisia and tardive dyskinesia. Its therfore not reccomended with parkinsons disease.
Metformin is a Biguanide used in the treatment of type 2 diabetes. Metformin can cause a metabolic acidosis and is essentially contraindicated in patients with a creatinine of >150. It should also be omitted prior to angiography because of the risks of contrast nephropathy.