Meds 2014

Question 1

Diclectin

Answer 1

1 tab = 10 mg

Indications and Clinical Use

Diclectin (doxylamine succinate and pyridoxine hydrochloride) is indicated for the management of nausea and vomiting of pregnancy.

Contraindications

Diclectin is contraindicated in patients who:

are hypersensitive to doxylamine succinate, other ethanolamine derivative antihistamines, pyridoxine hydrochloride or any nonmedicinal ingredient in the formulation;

are at risk for asthmatic attack;

have narrow angle glaucoma;

have stenosing peptic ulcer;

have pyloroduodenal obstruction;

have bladder-neck obstruction; or

receive monoamine oxidase inhibitors (MAOIs) [including linezolid, an antibiotic which is a reversible non-selective MAO inhibitor and methylthioninium chloride (methylene blue)]

Warnings and Precautions
Due to the anticholinergic properties of antihistamines, caution should be used when Diclectin is taken concurrently with other medications or alcohol.

No increased risk for malformations was found in first trimester exposures to doxylamine succinate and pyridoxine hydrochloride, with or without dicyclomine hydrochloride. A second meta-analysis, conducted by Einarson et al. incorporated 12 cohort and 5 case-control studies. No statistically significant relationships were found between first trimester use of the combination doxylamine succinate, pyridoxine hydrochloride with or without dicyclomine hydrochloride and fetal abnormalities.

Nursing Women

The molecular weight of doxylamine succinate is low enough that passage into breast milk should be expected. Paradoxical effects on a nursing infant can be expected, such as unusual excitement, irritability or sedation. Caution is recommended particularly in infants with apnea or other respiratory syndrome. Pyridoxine hydrochloride is excreted into breast milk, but in the doses provided in Diclectin, presents no risk to a nursing infant. Nursing mothers treated with Diclectin should not breastfeed or the use of Diclectin during lactation should be avoided.

Occupational Hazards

Diclectin may cause drowsiness. Caution must be exercised in activities requiring mental alertness such as driving a car or operating heavy machinery.

Adverse Drug Reaction Overview

The most common adverse reaction associated with doxylamine succinate is drowsiness. Other adverse drug reactions associated with doxylamine succinate may include: vertigo, nervousness, epigastric pain, headache, palpitation, diarrhea, disorientation, irritability, convulsions, urinary retention or insomnia.

Recommended Dose and Dosage Adjustment

Two (2) Diclectin delayed release tablets at bedtime to control nausea and vomiting occurring in the morning; additionally one (1) delayed release tablet in the morning and one (1) delayed release tablet mid-afternoon to control symptoms throughout the day. The dosage schedule may be individualized according to timing, duration, severity and frequency of the symptoms experienced by the patient. Diclectin can be prescribed in any trimester of pregnancy.

Diclectin is a delayed-release formulation that works optimally when given 4 to 6 hours prior to anticipated onset of symptoms. The delay in action may be prolonged when tablets are taken with food. However, based on the available data, the above recommended dosage schedule should be followed (see Action and Clinical Pharmacology, Pharmacokinetics).

Diclectin tablets being of a delayed release formulation should not be prescribed on an as needed basis (prn). It is important that Diclectin is taken daily for optimal effect.

A gradual tapering dose of Diclectin is recommended at the time of discontinuation to prevent a sudden onset of symptoms.

Missed Dose

In the event that a dose is missed, it should be taken as soon as possible. However, if it is almost time for the next dose, the missed dose should be skipped. The prescribed dosing schedule should be continued.

Administration

Diclectin tablets are to be taken orally. Diclectin tablets are a delayed release formulation therefore they should not be crushed or split.

Fatalities have been reported from doxylamine overdose. The overdose cases have been characterized by coma, grand mal seizures and cardiorespiratory arrest. Children appear to be at a high risk for cardiorespiratory arrest. A toxic dose for children of more than 1.8 mg/kg has been reported. A 3 year old child died 18 hours after ingesting 1000 mg doxylamine succinate. There is no correlation between the amount of doxylamine ingested, the doxylamine plasma level and clinical symptomatology.

Mechanism of Action

Diclectin (doxylamine succinate and pyridoxine hydrochloride) provides the action of two unrelated compounds. Doxylamine succinate (an antihistamine) and pyridoxine hydrochloride (vitamin B6) provide anti-nauseant and anti-emetic activity. The delayed action of Diclectin permits the nighttime dose to be effective in the morning hours, when the patient needs it most.