DesvenlafaxineDesvenlafaxine Succinate

About Desvenlafaxine

Desvenlafaxine is the main active substance the body makes from venlafaxine, and it is thought to work by raising serotonin and norepinephrine activity in the brain. Its label covers major depressive disorder in adults only; it is not approved for anyone under 18, and two eight-week studies in patients aged 7 to 17 did not show that it works. The recommended dose is 50 mg once a day, with or without food, which is both the starting and the usual dose: doses up to 400 mg a day worked in studies but added no benefit over 50 mg and caused more side effects. Moderate kidney impairment caps the dose at 50 mg a day, and severe impairment or end-stage kidney disease at 25 mg a day or 50 mg every other day; in moderate to severe liver impairment the recommended dose is 50 mg a day and going above 100 mg is not recommended.

The boxed warning, shared by all antidepressants, is that they raised the risk of suicidal thoughts and behavior in children, teenagers and young adults in short-term studies, so anyone starting it or changing the dose is watched for worsening mood or unusual behavior. It must not be combined with MAO inhibitors: 14 days must pass after stopping one before desvenlafaxine starts, and 7 days after stopping desvenlafaxine before an MAO inhibitor; it is not started in someone receiving linezolid or intravenous methylene blue, and anyone allergic to venlafaxine must not take it. Other warnings cover serotonin syndrome, raised blood pressure (which should be controlled before starting and checked regularly), bleeding, angle-closure glaucoma, mania, seizures, low sodium, a rare lung inflammation reported with venlafaxine, and sexual side effects. Nausea, dizziness, insomnia, sweating, constipation, sleepiness, loss of appetite and anxiety are common, and cholesterol and triglycerides can rise.

The extended-release tablet is swallowed whole, never divided, crushed, chewed or dissolved, and its empty shell may appear in the stool after the medicine has been absorbed. Stopping suddenly can cause dizziness, nausea, headache, irritability, sleep problems, sensory disturbances and even seizures, so the dose is lowered gradually; the 25 mg tablet is intended for tapering and is also the daily dose in severe kidney impairment, and the label notes that some people need several months to come off it. Exposure to SNRIs late in pregnancy can raise the risk of complications in the newborn, use in the month before delivery may raise the risk of heavy bleeding after birth, and urine drug screens can give a false positive for phencyclidine or amphetamine.

Taking Desvenlafaxine

How to take it

Once a day at about the same time, with or without food, swallowed whole with fluid; do not divide, crush, chew or dissolve the tablet. An empty tablet shell in the stool is normal and does not mean the dose was lost. Do not stop it on your own.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose and carry on as usual. Do not take a double dose.

Storage

At room temperature in the original, tightly closed container, away from heat and moisture (not in the bathroom), out of reach of children. Use a take-back program for unused tablets rather than flushing them.

Interactions to know about

MAO inhibitors, including linezolid and methylene blue, are not combined with it, and triptans, other antidepressants, certain opioids, lithium, buspirone, amphetamines, tryptophan and St. John’s wort add to the risk of serotonin syndrome. Aspirin, NSAIDs such as ibuprofen and naproxen, and warfarin raise the risk of bleeding. The Medication Guide says not to drink alcohol while taking it.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Desvenlafaxine differs from pharmacy to pharmacy

Generic desvenlafaxine has many makers, but it is not on every pharmacy’s flat-price list, so quotes for the same tablet differ from one pharmacy to the next. A prescription that names Pristiq and does not allow substitution is quoted at the brand price. Because the tablet cannot be split, each strength is bought as its own product, and a taper that steps down to 25 mg means a separate fill that a pharmacy which rarely dispenses it may need to order in.

Ways to pay less for Desvenlafaxine without insurance

• Ask for generic desvenlafaxine extended-release tablets, and make sure the prescription allows substitution rather than naming Pristiq only.
• Ask for a ninety-day supply once your dose is settled, and compare more than one pharmacy.
• If you are coming off it, ask the prescriber how the taper will be written, since the tablets cannot be split and the 25 mg strength is a separate fill.
• If cost is a barrier, ask the prescriber whether generic venlafaxine extended-release capsules, the older drug the body turns into desvenlafaxine, would suit you.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Desvenlafaxine

1. 1.Is my generic the same desvenlafaxine succinate tablet as Pristiq?
2. 2.How often should my blood pressure be checked while I take it?
3. 3.Could any of my pain relievers, migraine medicines or supplements interact with it?
4. 4.How would my dose be tapered if I need to stop?

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