Trimethoprim

Brand names

• Alti-Trimethoprim
• Apo-Sulfatrim [CD]
• Apo-Sulfatrim DS [CD]
• Bactrim [CD]
• Bactrim DS [CD]
• Bethaprim [CD]
• Comoxol {CD]
• Coptin [CD]
• Cotrim [CD]
• Novo-Trimel [CD]
• Novo-Trimel DS [CD]
• Nu-Cotrimox
• Polytrim
• Proloprim
• Protrin [CD]
• Protrin DF [CD]
• Roubac [CD]
• Septra [CD]
• Septra DS [CD]
• SMZ-TMP [CD]
• Sulfatrim D/S
• Trimpex
• Uroplus DS [CD]
• Uroplus SS [CD]

Usage

To treat urinary tract infections.

How it works

Trimethoprim kills bacteria by disrupting their ability to make necessary proteins.

Side effects

Serious

Sore throat, fever, pale skin, unusual bleeding or bruising, yellow tinge to the skin or eyes.

Common

Allergic skin reactions; itching.

Less common

Abdominal pain, nausea, vomiting, increased sensitivity to sunlight.

Possible interactions

Other medicaments:

Trimethoprim may increase the effects of:

• ACE inhibitors, resulting in dangerously increased potassium levels.
• amantadine (Symmetrel) and also result in increased levels of trimethoprim, resulting in toxicity.
• cyclosporine (Sandimmune) and result in increased kidney toxicity.
• dapsone and result in dapsone or trimethoprim toxicity.
• digoxin (Lanoxin), leading to toxicity.
• dofetilide (Tikosyn) may lead to heart toxicity. Avoid this combination.
• lamivudine (Epivir) and adjustments in lamivudine doses may be required.
• metformin (Glucophage) and other cationic medicaments.
• methotrexate (Mexate), leading to toxicity.
• phenytoin (Dilantin) or fosphenytoin (Cerebyx) and cause phenytoin or fosphenytoin toxicity.
• procainamide (Procan SR) and result in procainamide toxicity.
• zidovudine (AZT), leading to increased toxicity risk.

The following medicaments may decrease the effects of trimethoprim:



• cholestyramine (Questran) and perhaps other cholesterol-lowering medicines of the same class-these will bind trimethoprim and blunt its beneficial effects by inhibiting absorption.
• rifampin (Rifadin, Rimactane).
• ritonavir (Norvir).

Foods:

Since this medicine may increase homocysteine levels, a multivitamin appears prudent.

Herbal medicines or minerals:

Some patients use Echinacea to attempt to boost their immune systems. Unfortunately, Echinacea is not recommended in people with damaged immune systems. This herb may also actually weaken any immune system if it is used too often or for too long a time. Do not take mistletoe herb, oak bark or marshmallow root and licorice extracts. Pure cranberry juice may help keep harmful bacteria from attaching to the bladder wall and may be useful in combination with antibiotics in helping to prevent urinary tract infections.