Effexor can you overdose

Venlafaxine and desvenlafaxine can cause seizures in therapeutic dosing, albeit rarely, and the risk is magnified in overdose. There are several case series published in the literature where venlafaxine ranks fairly high as one of the common causes of drug-induced seizures. It is important to know that seizures may be delayed hours after the ingestion.

Missouri Poison Center has followed cases where seizures have occurred up to hours after the ingestion. Why would this be? After venlafaxine reaches peak serum concentration its active metabolite, O-desmethylvenlafaxine ODV continues to be formed.

Furthermore, since ODV half-life is longer hours , it will gradually accumulate to an even greater degree. Eventually after overdose the blood concentrations of parent drug and active metabolite can rise into a range that is risky for seizures, and will stay in that range for some time. Thus, side effects including seizures can be delayed in onset and prolonged or recurrent.

It is not fully known how venlafaxine and desvenlafaxine induce seizures, but it is likely due its effects on multiple neurotransmitters important in seizure genesis and extinction. Laboratory monitoring for patients with venlafaxine overdose include routine metabolic panel and creatinine kinase, along with a lead EKG and continuous cardiac monitoring.

Of note, venlafaxine can cause a false-positive for PCP or amphetamines on some urine drug screens. There is no specific antidote; treatment is symptomatic and supportive:.

Venlafaxine and desvenlafaxine overdoses can be challenging to manage and symptoms may become severe. Our advice to you is to call the Missouri Poison Center. Our specially trained nurses, pharmacists and medical toxicologist can provide you with the most up-to-date treatment advice on venlafaxine and other SNRI exposures.

Call Now. There is also a risk of serotonin toxicity in overdose. There are active metabolites, so symptoms can be prolonged. Lethal outcomes have been seen at doses as low as 2, mg 2 g. Most cases of fatal overdoses involve more than one drug. Most cases of MAOI toxicity happen when large doses are taken along with alcohol or other drugs. Severe symptoms of an overdose can occur if you take more than 2 mg per kg of your body weight.

Overdosing on antidepressants can cause mild to severe symptoms. In some cases, death is possible. People who overdose on antidepressants may also experience serotonin syndrome. Serotonin syndrome is a serious negative drug reaction that occurs when too much serotonin builds up in your body. As with most medications, antidepressants can cause mild side effects even at a low dose.

The most common side effects include:. The side effects may be uncomfortable at first, but they generally improve with time. Depending on your symptom severity, your doctor may want to reduce your dosage or switch you to a different medication. If you suspect an overdose has occurred, seek emergency medical care right away.

Certain types of antidepressants, especially MAOIs , may not cause severe symptoms for up to 24 hours after overdosing. In the United States, you can contact the National Capital Poison Center at and await further instructions. If symptoms become severe, call your local emergency services. Try to stay calm and keep your body cool while you wait for emergency personnel to arrive. In the case of an overdose, emergency personnel will transport you to the hospital or emergency room.

You may be given activated charcoal while en route. This can help absorb the medication and alleviate some of your symptoms. When you arrive at the hospital or emergency room, your doctor may pump your stomach to remove any remaining medication. Intravenous IV fluids may also be necessary to replenish essential nutrients and prevent dehydration.

Venlafaxine Effexor , a serotonin and norepinephrine reuptake inhibitor, entered the Canadian market in As with any new medication, experience with overdose was extremely limited when venlafaxine was introduced. Although only 12 suicide attempts had been recorded at launch, because there were no deaths and only one seizure, it was hoped that it would be safer in overdose than other antidepressants.

By , numerous overdose cases from poison centres reported tachycardia, hypotension, seizures, coma, serotonin syndrome, and death. The relative toxicity of venlafaxine in overdose compared with other antidepressants was first highlighted in an analysis of United Kingdom mortality data published in Among serotonergic antidepressants, the maximum fatal toxicity index was 3.

DPIC experience is consistent with published literature, with numerous cases of both adults and teens exhibiting tachycardia, hypotension, serotonin syndrome, and precipitous seizures following venlafaxine overdose as well as cases of QTc prolongation and QRS widening.

In the interest of patient safety and pharmacovigilance, DPIC continues to gather data on venlafaxine overdose in BC, to advise on case management, and to follow up for outcomes. Accumulating evidence of fatalities has recently prompted Wyeth in the United States to revise its Effexor prescribing information. To increase awareness of the serious problems with venlafaxine overdose, DPIC has recently highlighted venlafaxine toxicity in its Toxic Update Newsletter.

This is being distributed to emergency departments and interested physicians throughout BC. To obtain a copy or to be placed on the newsletter distribution list, e-mail your request to info dpic. Montgomery SA. Venlafaxine: A new dimension in antidepressant pharmacotherapy. J Clin Psychiatry ; PubMed Citation 2.