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phenindamine

Generic Name: phenindamine (fe NIN da meen)
Brand Name: Nolahist

What is phenindamine?

Phenindamine is an antihistamine. Phenindamine blocks the effects of the naturally occurring chemical histamine in your body.

Phenindamine is used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.

Phenindamine may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about phenindamine?

Use caution when driving, operating machinery, or performing other hazardous activities. Phenindamine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.

Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking phenindamine.

Who should not take phenindamine?

Do not take phenindamine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Before taking this medication, tell your doctor if you have

  • glaucoma or increased pressure in the eye;

  • a stomach ulcer;

  • an enlarged prostate, bladder problems or difficulty urinating;

  • an overactive thyroid (hyperthyroidism);

  • hypertension or any type of heart problems; or

  • asthma.

You may not be able to take phenindamine, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

It is not known whether phenindamine will harm an unborn baby. Do not take phenindamine without first talking to your doctor if you are pregnant.

Infants are especially sensitive to the effects of antihistamines, and serious side effects could occur in a nursing baby. Phenindamine is not recommended if you are breast-feeding a baby. Do not take phenindamine without first talking to your doctor if you are nursing a baby.

If you are over 60 years of age, you may be more likely to experience side effects from phenindamine. You may require a lower dose of this medication.

How should I take phenindamine?

Take phenindamine exactly as directed in the package or as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

Phenindamine can be taken with or without food.

Never take more of this medication than is prescribed for you. The maximum amount of phenindamine that you should take in 1 day is 75 mg.

Store phenindamine at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and take only your next regularly scheduled dose. Do not take a double dose of this medication unless otherwise directed by your doctor.

What happens if I overdose?

Seek emergency medical attention.

Symptoms of a phenindamine overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.

What should I avoid while taking phenindamine?

Use caution when driving, operating machinery, or performing other hazardous activities. Phenindamine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.

Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking phenindamine.

Phenindamine side effects

Stop taking phenindamine and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).

Other, less serious side effects may be more likely to occur. Continue to take phenindamine and talk to your doctor if you experience

  • sleepiness, fatigue, or dizziness;

  • headache;

  • dry mouth; or

  • difficulty urinating or an enlarged prostate.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect phenindamine?

Do not take phenindamine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Talk to your pharmacist before taking other over-the-counter cough, cold, allergy, or insomnia medications. These products may contain medicines similar to phenindamine, which could lead to an overdose of antihistamine.

Before taking this medication, tell your doctor if you are taking any of the following medicines:

  • anxiety or sleep medicines such as alprazolam (Xanax), diazepam (Valium), chlordiazepoxide (Librium), temazepam (Restoril), or triazolam (Halcion);

  • medications for depression such as amitriptyline (Elavil), doxepin (Sinequan), nortriptyline (Pamelor), fluoxetine (Prozac), sertraline (Zoloft), or paroxetine (Paxil); or

  • any other medications that make you feel drowsy, sleepy, or relaxed.

Drugs other than those listed here may also interact with phenindamine. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.

Further information

  • Your pharmacist has more information about phenindamine written for health professionals that you may read.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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