1 What is Nallpen?

Brand: Nallpen, Unipen

Generic: Nafcillin

Nallpen is an antibiotic drug under the penicillin group, used to treat infections caused by bacteria, particularly staphylococcus.


Read your medication guide and follow your doctor’s prescription at all times.

  • Nallpen is administered via injection into the vein that must be infused for up to 1 hour, usually given every 4 hours per doctor’s prescription.
  • Note that mostly, only health care professionals administer this medication to you in a hospital or clinic setting. Do not self- inject unless if you have sufficient understanding and skill in administering this medication at home with your doctor’s approval and guidance.
  • The dosage depends on your medical condition or treatment response. Do not adjust your dose without your doctor’s recommendation.
  • Do not use if there are particles or discoloration noted in the content of this medication.
  • Do not reuse or recycle disposable needles, IV tubing and other medical supplies used in administering this medication.
  • Discard needles safely in a puncture- proof container.
  • Continue using Nallpen on a regular schedule (same time of the day). Do not stop using this medication abruptly without consulting your doctor to prevent relapse of the infection.

Inform your doctor immediately if your condition aggravates or does not improve.

Have your health care provider administer your missed dose as soon as possible. However, make sure that the time interval between the missed and the next dose is not too close. Otherwise, stick with the regular schedule and leave out the missed dose. Do not double dose to cover up a missed dose.

Record your missed dose and inform your doctor immediately if you missed several doses.


Nallpen may interact with:

  • Cyclosporine
  • Blood thinner (i.e. warfarin) and
  • Other antibiotics (i.e. doxycycline, minocycline, tetracycline)

Some drugs may either lessen the beneficial effects or worsen the side effects of Nallpen. Likewise, Nallpen may make some drugs less efficient or intensify their side effects.

Make sure to inform your doctor about all other drugs you are currently taking or using (prescribed and non-prescribed medications including vitamins, minerals, and herbal products) to check for possible drug interaction with Nallpen.

Never alter the doses of other medications while on Nallpen neither stop nor start any medicine without the doctor’s recommendation.

Side Effects:

There are no side effects known aside from a possible allergic reaction in people who have previous or unknown hypersensitivity to the drug.

Watch out for signs of allergic reactions such as:

  • Rash
  • Itching
  • Swelling


Before taking Nallpen, tell your health care provider if you have/are:

  • Any allergies to any substance, food or medication, particularly to nafcillin (Nallpen) or other penicillin and cephalosporin antibiotics;
  • Medical history or a present condition such as:

        o Asthma

        o Liver disease

        o Kidney problem and

  • Pregnant, planning to get pregnant or currently breastfeeding a baby (Nallpen has no expected harmful effects to the unborn child but it can pass through breast milk that may harm the nursing child. The risks and benefits of using this medication during pregnancy must be discussed well with your doctor.)