Anti-Malarial Drug Effects on Hearing and Balance, part 2

HHTM Staff

Two weeks ago our post described malaria the disease, along with the disease’s murky connection to hearing loss.  Today’s post discusses five drugs used to prevent malaria.  Some of these are known causes of sensorineural hearing loss which may or may not be reversible; others produce auditory/vestibular symptoms such as tinnitus and dizziness.

   

Malaria Prevention — Not so Easy

 

http://www.who.int/infectious-disease-report/2000/graphs/4_malaria.htm
WHO 2000 report map

Mosquito avoidance is at the top of the list for preventing malaria. Indoor use of pesticides is also used. For travelers, there are five drug options which form the “chemoprophylactic” regimen recommended by the CDC for regions in which malaria is endemic: mefloquine,  doxycycline,  atovaquone/proguanil, chloroquine, primaquine.  But only 6% of those who contracted malaria in 2011 reported that they had followed CDC guidelines correctly.

There are reasons for the low compliance:

“When deciding which drug to use, consider specific itinerary, length of trip, cost of drug, previous adverse reactions to antimalarials, drug allergies, and current medical history. All travelers should seek medical attention in the event of fever during or after return from travel to areas with malaria.”

  • Preventive treatments don’t always prevent malaria.  Upwards of 30% of travelers who returned to the US in 2011 with malaria reported taking antimalarial medications.  Drug resistant strains of malaria are common in different parts of the world, which is why there are different drug regimes for different regions.  For example, the map above is hard to read but the take-home is that countries in dark green have a form of malaria that is resistant to chloroquine.
  • Part of the non-compliance is that not everyone took the recommended drugs and a majority reported missing doses. Some took the “wrong” drugs for the region they visited; others may not have been able to access the right drugs (they’re not all available everywhere).
  • Preventive measures bring their own dangers.   Mefloquine (Larium) was recently banned by the chief med adviser for US special forces worldwide because of rare but severe side effects including psychosis and  brain damage in rare cases.  As of 2013, the FDA requires a black box warning for Larium.   Other drugs (e.g., chloroquine) have been known ototoxic medications for decades.  Dr. Alan Desmond also reported in 2013 on the connection of hearing loss and Melfloquine.

 Anti-Malarial Chemoprophylactic Drugs and Auditory/Vestibular Side Effects

 

Anti-Malarial drug

Auditory/Vestibular Effects

mefloquineHearing Loss, tinnitus, dizziness, loss of balance
doxycyclinedizziness
atovaquone/proguanilDizziness, vertigo
ChloroquineHearing loss, tinnitus, dizziness
primaquineDizziness; hearing loss with chronic overdose
None of the five drugs in the chemoprophylactic regimen come without auditory/vestibular side effects, although doxycycline may come close (there’s some controversy on this).  While the risks are clear, the greater risk of contracting malaria in some countries argues for following CDC guidelines.

The Audiology Connection

 

In all cases in which these medications are taken prophylactically, it is in the traveler’s best interest to obtain pre- and post-travel audiograms to monitor effects, if any, of the antimalarial regime on hearing.  That line of thinking will be pursued next in the series when it comes to the drugs and drug effects associated with treatment of malaria itself.
feature image courtesy of National Geographic